History of issues with LS7 engine in Road racing
12-30-2014, 04:36 PM
#1
History of issues with LS7 engine in Road racing Hi,
If anybody is considering using a stock LS7 engine for hard out road racing you might want to read this short history of what we as the Premier Tin-Top category here in New Zealand learned about running basically stock LS7 internal component's in the last three years.
Its fair to say that we dived in at the deep end and purchased a crate engine LS7 [after reading about that engine being used in the MT 900R Mosler] as the proposed controlled spec engine for a prototype car road racing car we developed for a new category of 4 door tin-top racing here in New Zealand, known as V8Supertourers, which is modeled on a highly controlled version of the Australian V8 Supercar Series car, in order to save on both build and running cost's but have similar levels of performance.
Under my tenure as the CEO of V8ST, we built 22 V8ST car's, including the prototype V8Supertourer, all with LS7 stock standard crate engines that we purchased through Chuck at Pace Performance Ohio. At last count we had purchased close to 30 complete LS7 engine's, and at least 15 long [Service] engine's.
Our problems with the engines started at the very first race meeting were we had 16 V8ST race cars on the grid [8 with Holden VE2 Body panels, and 8 with Ford Falcon FG Body panels] the problems started with the close drafting nature of such a controlled category we each competitor has the same potential lap time, and with track temperatures around 40ēC a number of cars engines ran hot on both the water and the oil, something we had not experienced at all with the single prototype car that had always run on it own.
I could and probably should right a book on the drama's, engine blow ups etc, and the instant experts who suddenly appeared with how to fix it solutions many of which were adopted and in some cases showed small gains.
I became more and more convinced that the principle problem was that any engine rev's higher than 6,000 rpm that the scavenge g'rotor was incapable of returning the same volume of oil that was being delivered by the pressure side of the standard so called OE dry-sump pump, and as such the volume of oil in the sump was so excessive that the crank and rod's acted like a giant egg-better and beat the oil into a highly aerated super hot froth, which was a recipe for disaster.
In desperation we mandated a maximum RPM of 6,250 and limped along for the first year with out any further blown engines, until I was able to gain sufficient competitor "buy-in" to have Bill Dailey from Dailey Engineering design and build us a 3 stage, integrated Pump and billet pan to fit, without any modification's just in front of the left hand engine mount.
This was an immediate success and bought both the oil and water temperatures into near perfect operating temperatures.
Once we were on top of the temperature and oiling issues, we were able to focus on the occasional catastrophic [rod through the side of the block] engine failures that were were still experiencing. By analyzing the onboard data we finally determined that RED-MIST downshifts possible even with our sequential 6 speed Quaife gearboxes, were responsible for causing a momentary over-rev under braking compression, which literally pulled the wrist pin out of the piston gudgeon boss's.
We were about to bite the bullet and mandate a change to Mahle's off the shelf forged piston, when we discovered quite by chance the GM had secretly introduced a modified hypeautectic piston, that you had to buy along with a slightly modified Ti rod to suit the strengthened piston's. We also discovered again by chance that GM were fitting the new rod and piston, as standard to their so called Service engine [long engine in our terminology] which made a lot more sense to purchase because all the wear parts were new at a reasonable, at least to us cost of US$10,500 less core cost, if you had one which we didn't.
This Service engine solution, though only a bandage in my opinion meant that those competitor's that had not lost an engine, didn't feel forced to tear down their engine in order to fit a forged piston even though we were convince there would be no performance advantage.
Along the way we discovered the reason for almost all the ti-rod's big end galling when the side's touch each other, this lead us to allow controlled Blue printing to deal with the unbelievable bad tolerance GM allow in the build of their engines, which is bordering on Corporate negligence at least in my opinion. We found little-end wrist pin clearances down to 0.0003 and up to 0.001.5 !. As the little-end 'steers' the rod its no wonder the big end's side's get into contact at some point in time given the complex secondary harmonic's that exist in all engines to a lessor or greater extent.
We all so found size for size piston and bore's plus badly tapered bores, such a shame with such a great engine, but nothing that a full on blueprint cant fix.
All of this said I have become a huge fan of the LS engine and am currently building a normally aspirated 800BHP, 8,500 RPM 3.625" short stroke screamer, with a 4.185" bore, using a GEN4 Truck block and MID wet sleeves from Steve at RED in California. As the build goes along I am happy to share it with all the LS engine fan's on this site, so I will start a new thread on the build in the next few week's.
Happy new year to you all from down under,
Mark.
If anybody is considering using a stock LS7 engine for hard out road racing you might want to read this short history of what we as the Premier Tin-Top category here in New Zealand learned about running basically stock LS7 internal component's in the last three years.
Its fair to say that we dived in at the deep end and purchased a crate engine LS7 [after reading about that engine being used in the MT 900R Mosler] as the proposed controlled spec engine for a prototype car road racing car we developed for a new category of 4 door tin-top racing here in New Zealand, known as V8Supertourers, which is modeled on a highly controlled version of the Australian V8 Supercar Series car, in order to save on both build and running cost's but have similar levels of performance.
Under my tenure as the CEO of V8ST, we built 22 V8ST car's, including the prototype V8Supertourer, all with LS7 stock standard crate engines that we purchased through Chuck at Pace Performance Ohio. At last count we had purchased close to 30 complete LS7 engine's, and at least 15 long [Service] engine's.
Our problems with the engines started at the very first race meeting were we had 16 V8ST race cars on the grid [8 with Holden VE2 Body panels, and 8 with Ford Falcon FG Body panels] the problems started with the close drafting nature of such a controlled category we each competitor has the same potential lap time, and with track temperatures around 40ēC a number of cars engines ran hot on both the water and the oil, something we had not experienced at all with the single prototype car that had always run on it own.
I could and probably should right a book on the drama's, engine blow ups etc, and the instant experts who suddenly appeared with how to fix it solutions many of which were adopted and in some cases showed small gains.
I became more and more convinced that the principle problem was that any engine rev's higher than 6,000 rpm that the scavenge g'rotor was incapable of returning the same volume of oil that was being delivered by the pressure side of the standard so called OE dry-sump pump, and as such the volume of oil in the sump was so excessive that the crank and rod's acted like a giant egg-better and beat the oil into a highly aerated super hot froth, which was a recipe for disaster.
In desperation we mandated a maximum RPM of 6,250 and limped along for the first year with out any further blown engines, until I was able to gain sufficient competitor "buy-in" to have Bill Dailey from Dailey Engineering design and build us a 3 stage, integrated Pump and billet pan to fit, without any modification's just in front of the left hand engine mount.
This was an immediate success and bought both the oil and water temperatures into near perfect operating temperatures.
Once we were on top of the temperature and oiling issues, we were able to focus on the occasional catastrophic [rod through the side of the block] engine failures that were were still experiencing. By analyzing the onboard data we finally determined that RED-MIST downshifts possible even with our sequential 6 speed Quaife gearboxes, were responsible for causing a momentary over-rev under braking compression, which literally pulled the wrist pin out of the piston gudgeon boss's.
We were about to bite the bullet and mandate a change to Mahle's off the shelf forged piston, when we discovered quite by chance the GM had secretly introduced a modified hypeautectic piston, that you had to buy along with a slightly modified Ti rod to suit the strengthened piston's. We also discovered again by chance that GM were fitting the new rod and piston, as standard to their so called Service engine [long engine in our terminology] which made a lot more sense to purchase because all the wear parts were new at a reasonable, at least to us cost of US$10,500 less core cost, if you had one which we didn't.
This Service engine solution, though only a bandage in my opinion meant that those competitor's that had not lost an engine, didn't feel forced to tear down their engine in order to fit a forged piston even though we were convince there would be no performance advantage.
Along the way we discovered the reason for almost all the ti-rod's big end galling when the side's touch each other, this lead us to allow controlled Blue printing to deal with the unbelievable bad tolerance GM allow in the build of their engines, which is bordering on Corporate negligence at least in my opinion. We found little-end wrist pin clearances down to 0.0003 and up to 0.001.5 !. As the little-end 'steers' the rod its no wonder the big end's side's get into contact at some point in time given the complex secondary harmonic's that exist in all engines to a lessor or greater extent.
We all so found size for size piston and bore's plus badly tapered bores, such a shame with such a great engine, but nothing that a full on blueprint cant fix.
All of this said I have become a huge fan of the LS engine and am currently building a normally aspirated 800BHP, 8,500 RPM 3.625" short stroke screamer, with a 4.185" bore, using a GEN4 Truck block and MID wet sleeves from Steve at RED in California. As the build goes along I am happy to share it with all the LS engine fan's on this site, so I will start a new thread on the build in the next few week's.
Happy new year to you all from down under,
Mark.
01-01-2015, 04:37 PM
#2
On The Tree
Hi,
If anybody is considering using a stock LS7 engine for hard out road racing you might want to read this short history of what we as the Premier Tin-Top category here in New Zealand learned about running basically stock LS7 internal component's in the last three years.
Its fair to say that we dived in at the deep end and purchased a crate engine LS7 [after reading about that engine being used in the MT 900R Mosler] as the proposed controlled spec engine for a prototype car road racing car we developed for a new category of 4 door tin-top racing here in New Zealand, known as V8Supertourers, which is modeled on a highly controlled version of the Australian V8 Supercar Series car, in order to save on both build and running cost's but have similar levels of performance.
Under my tenure as the CEO of V8ST, we built 22 V8ST car's, including the prototype V8Supertourer, all with LS7 stock standard crate engines that we purchased through Chuck at Pace Performance Ohio. At last count we had purchased close to 30 complete LS7 engine's, and at least 15 long [Service] engine's.
Our problems with the engines started at the very first race meeting were we had 16 V8ST race cars on the grid [8 with Holden VE2 Body panels, and 8 with Ford Falcon FG Body panels] the problems started with the close drafting nature of such a controlled category we each competitor has the same potential lap time, and with track temperatures around 40ēC a number of cars engines ran hot on both the water and the oil, something we had not experienced at all with the single prototype car that had always run on it own.
I could and probably should right a book on the drama's, engine blow ups etc, and the instant experts who suddenly appeared with how to fix it solutions many of which were adopted and in some cases showed small gains.
I became more and more convinced that the principle problem was that any engine rev's higher than 6,000 rpm that the scavenge g'rotor was incapable of returning the same volume of oil that was being delivered by the pressure side of the standard so called OE dry-sump pump, and as such the volume of oil in the sump was so excessive that the crank and rod's acted like a giant egg-better and beat the oil into a highly aerated super hot froth, which was a recipe for disaster.
In desperation we mandated a maximum RPM of 6,250 and limped along for the first year with out any further blown engines, until I was able to gain sufficient competitor "buy-in" to have Bill Dailey from Dailey Engineering design and build us a 3 stage, integrated Pump and billet pan to fit, without any modification's just in front of the left hand engine mount.
This was an immediate success and bought both the oil and water temperatures into near perfect operating temperatures.
Once we were on top of the temperature and oiling issues, we were able to focus on the occasional catastrophic [rod through the side of the block] engine failures that were were still experiencing. By analyzing the onboard data we finally determined that RED-MIST downshifts possible even with our sequential 6 speed Quaife gearboxes, were responsible for causing a momentary over-rev under braking compression, which literally pulled the wrist pin out of the piston gudgeon boss's.
We were about to bite the bullet and mandate a change to Mahle's off the shelf forged piston, when we discovered quite by chance the GM had secretly introduced a modified hypeautectic piston, that you had to buy along with a slightly modified Ti rod to suit the strengthened piston's. We also discovered again by chance that GM were fitting the new rod and piston, as standard to their so called Service engine [long engine in our terminology] which made a lot more sense to purchase because all the wear parts were new at a reasonable, at least to us cost of US$10,500 less core cost, if you had one which we didn't.
This Service engine solution, though only a bandage in my opinion meant that those competitor's that had not lost an engine, didn't feel forced to tear down their engine in order to fit a forged piston even though we were convince there would be no performance advantage.
Along the way we discovered the reason for almost all the ti-rod's big end galling when the side's touch each other, this lead us to allow controlled Blue printing to deal with the unbelievable bad tolerance GM allow in the build of their engines, which is bordering on Corporate negligence at least in my opinion. We found little-end wrist pin clearances down to 0.0003 and up to 0.001.5 !. As the little-end 'steers' the rod its no wonder the big end's side's get into contact at some point in time given the complex secondary harmonic's that exist in all engines to a lessor or greater extent.
We all so found size for size piston and bore's plus badly tapered bores, such a shame with such a great engine, but nothing that a full on blueprint cant fix.
All of this said I have become a huge fan of the LS engine and am currently building a normally aspirated 800BHP, 8,500 RPM 3.625" short stroke screamer, with a 4.185" bore, using a GEN4 Truck block and MID wet sleeves from Steve at RED in California. As the build goes along I am happy to share it with all the LS engine fan's on this site, so I will start a new thread on the build in the next few week's.
Happy new year to you all from down under,
Mark.
If anybody is considering using a stock LS7 engine for hard out road racing you might want to read this short history of what we as the Premier Tin-Top category here in New Zealand learned about running basically stock LS7 internal component's in the last three years.
Its fair to say that we dived in at the deep end and purchased a crate engine LS7 [after reading about that engine being used in the MT 900R Mosler] as the proposed controlled spec engine for a prototype car road racing car we developed for a new category of 4 door tin-top racing here in New Zealand, known as V8Supertourers, which is modeled on a highly controlled version of the Australian V8 Supercar Series car, in order to save on both build and running cost's but have similar levels of performance.
Under my tenure as the CEO of V8ST, we built 22 V8ST car's, including the prototype V8Supertourer, all with LS7 stock standard crate engines that we purchased through Chuck at Pace Performance Ohio. At last count we had purchased close to 30 complete LS7 engine's, and at least 15 long [Service] engine's.
Our problems with the engines started at the very first race meeting were we had 16 V8ST race cars on the grid [8 with Holden VE2 Body panels, and 8 with Ford Falcon FG Body panels] the problems started with the close drafting nature of such a controlled category we each competitor has the same potential lap time, and with track temperatures around 40ēC a number of cars engines ran hot on both the water and the oil, something we had not experienced at all with the single prototype car that had always run on it own.
I could and probably should right a book on the drama's, engine blow ups etc, and the instant experts who suddenly appeared with how to fix it solutions many of which were adopted and in some cases showed small gains.
I became more and more convinced that the principle problem was that any engine rev's higher than 6,000 rpm that the scavenge g'rotor was incapable of returning the same volume of oil that was being delivered by the pressure side of the standard so called OE dry-sump pump, and as such the volume of oil in the sump was so excessive that the crank and rod's acted like a giant egg-better and beat the oil into a highly aerated super hot froth, which was a recipe for disaster.
In desperation we mandated a maximum RPM of 6,250 and limped along for the first year with out any further blown engines, until I was able to gain sufficient competitor "buy-in" to have Bill Dailey from Dailey Engineering design and build us a 3 stage, integrated Pump and billet pan to fit, without any modification's just in front of the left hand engine mount.
This was an immediate success and bought both the oil and water temperatures into near perfect operating temperatures.
Once we were on top of the temperature and oiling issues, we were able to focus on the occasional catastrophic [rod through the side of the block] engine failures that were were still experiencing. By analyzing the onboard data we finally determined that RED-MIST downshifts possible even with our sequential 6 speed Quaife gearboxes, were responsible for causing a momentary over-rev under braking compression, which literally pulled the wrist pin out of the piston gudgeon boss's.
We were about to bite the bullet and mandate a change to Mahle's off the shelf forged piston, when we discovered quite by chance the GM had secretly introduced a modified hypeautectic piston, that you had to buy along with a slightly modified Ti rod to suit the strengthened piston's. We also discovered again by chance that GM were fitting the new rod and piston, as standard to their so called Service engine [long engine in our terminology] which made a lot more sense to purchase because all the wear parts were new at a reasonable, at least to us cost of US$10,500 less core cost, if you had one which we didn't.
This Service engine solution, though only a bandage in my opinion meant that those competitor's that had not lost an engine, didn't feel forced to tear down their engine in order to fit a forged piston even though we were convince there would be no performance advantage.
Along the way we discovered the reason for almost all the ti-rod's big end galling when the side's touch each other, this lead us to allow controlled Blue printing to deal with the unbelievable bad tolerance GM allow in the build of their engines, which is bordering on Corporate negligence at least in my opinion. We found little-end wrist pin clearances down to 0.0003 and up to 0.001.5 !. As the little-end 'steers' the rod its no wonder the big end's side's get into contact at some point in time given the complex secondary harmonic's that exist in all engines to a lessor or greater extent.
We all so found size for size piston and bore's plus badly tapered bores, such a shame with such a great engine, but nothing that a full on blueprint cant fix.
All of this said I have become a huge fan of the LS engine and am currently building a normally aspirated 800BHP, 8,500 RPM 3.625" short stroke screamer, with a 4.185" bore, using a GEN4 Truck block and MID wet sleeves from Steve at RED in California. As the build goes along I am happy to share it with all the LS engine fan's on this site, so I will start a new thread on the build in the next few week's.
Happy new year to you all from down under,
Mark.
01-01-2015, 06:31 PM
#3
However, once we realised what the oiling problem was we installed a bolt on Aviad single stage scavenge pump, and that fixed the main issue with the excess oil in the sump and the resulting heat and windage issues.
The tolerances although unacceptable in my view, don't seem to present that much of an issue, in terms of engine reliability, but obviously will cause some engines to run hotter that other's etc.
The Titanium galling of the big-end side cheeks will most likely not show up until you tear down an engine, because the standard oiling system catches them before they get into the relief valve, and jam that either open or shut.
Losing a rod through the side by crabbing the wrong gear under heavy breaking will probably result in a rod hanging out of the side of the engine block, so I would definitely suggest anybody road racing a manual gearbox, change out the piston's to a good quality forged piston, and also change out the wrist-pin bushing to a full sleeve type.
If anybody wants to ask me anything at all about the LS7 for normally aspirated road racing applications just PM me or post it on this site for the interest of the whole community.
Have a great new year everybody.
Mark.
01-03-2015, 03:31 PM
#4
Thanks for sharing Mark, I'm a huge fan of touring car racing down under, both you and the boys in Australia. You both have great products.
Your findings echo what goes on here, the LS oiling systems are severely lacking. Once that issue is addressed, these motors are awesome on track. Oiling mods make them more reliable, and they make awesome torque to pull out of corners.
As far as the downshifting issue, everyone is guilty of seeing the red mist. Not much you can do about racers in the heat of the moment, feeding it gears to make that dive bomb pass. You can tell the Aussie v8's are built to handle far more RPM than the 7500 they are limited to, they absolutely lay those things against the rev limit when downshifting. Sometimes it sounds like they are well over 8000 rpm when they are making a heroic pass.
Your findings echo what goes on here, the LS oiling systems are severely lacking. Once that issue is addressed, these motors are awesome on track. Oiling mods make them more reliable, and they make awesome torque to pull out of corners.
As far as the downshifting issue, everyone is guilty of seeing the red mist. Not much you can do about racers in the heat of the moment, feeding it gears to make that dive bomb pass. You can tell the Aussie v8's are built to handle far more RPM than the 7500 they are limited to, they absolutely lay those things against the rev limit when downshifting. Sometimes it sounds like they are well over 8000 rpm when they are making a heroic pass.
01-03-2015, 05:28 PM
#5
Thanks for sharing Mark, I'm a huge fan of touring car racing down under, both you and the boys in Australia. You both have great products.
Your findings echo what goes on here, the LS oiling systems are severely lacking. Once that issue is addressed, these motors are awesome on track. Oiling mods make them more reliable, and they make awesome torque to pull out of corners.
As far as the downshifting issue, everyone is guilty of seeing the red mist. Not much you can do about racers in the heat of the moment, feeding it gears to make that dive bomb pass. You can tell the Aussie v8's are built to handle far more RPM than the 7500 they are limited to, they absolutely lay those things against the rev limit when downshifting. Sometimes it sounds like they are well over 8000 rpm when they are making a heroic pass.
Your findings echo what goes on here, the LS oiling systems are severely lacking. Once that issue is addressed, these motors are awesome on track. Oiling mods make them more reliable, and they make awesome torque to pull out of corners.
As far as the downshifting issue, everyone is guilty of seeing the red mist. Not much you can do about racers in the heat of the moment, feeding it gears to make that dive bomb pass. You can tell the Aussie v8's are built to handle far more RPM than the 7500 they are limited to, they absolutely lay those things against the rev limit when downshifting. Sometimes it sounds like they are well over 8000 rpm when they are making a heroic pass.
Thanks for the kind word's, I agree that when you know how to make the Ls7 live its a truly amazing engine.
Our some what utopian idea was to not allow any refurbishment of the engine, and to carry enough spare brand new engines to cover the odd blow up and anybody that thought they were down on power etc. We were buying the engines in bulk at a little over US$12K which is really cheap HP and torque in any bodies language. Incidentally we dyno'd the first 25 engines in a marathon back to back 10 day spell and with the stock Ls7 headers, dumping straight into a large fabricated collector and then speedway style merging into the dyno's 10" exhaust collector, they all made 555 BHP plus or minus 3 BHP SAE corrected on the latest Superflow bench dyno.
Sadly, we struck severe over heating oil and water problems, and started losing engines and panic took over, the rest is history.
Suffice to say if we knew what we know now, we would have purchased the engine pool and blue printed all the engines, and to keep cost's down just fitted Aviad's twin sump pick up's and single stage scavenge pump as can be seen on the left hand side of the engine bolted to the front of the left hand cylinder head.
The photo below shows our V8ST Prototype race car, now in private hands and competing in the NZ Endurance Series [6 races over 3 hours each] and the engine is still the original crate engine, totally stock standard, other than the Avaid secondary scavenge pump shown above, and has completed more than 7,000 Km's of hard out track time, with many different drivers.
Cheers,
Mark.
01-04-2015, 04:02 PM
#6
So you are just using the factory LS7 pressure pump, with a single stage scavenge? This is very encouraging, I have been looking at a similar system when I rebuild my engine.
01-04-2015, 05:43 PM
#7
Well, as you know the Ls7 has two G'rotor's, one for pressure and the other for scavenge. Aviad's single stage secondary scavenge pump uses a second oil pic-up that mounts through the side of the standard so called dry-sump pan, so you need to drop the pan, which you can also do in place [at least we were on our race car, sorry don't know about a road car] and fit the gated collector box and drill through the side of the pan etc. So you now have 2 vacuum stages and one pressure stage. Its also possible to go bigger and better on the secondary scavenge pump and pull a true vacuum.
We found that you can safely pull 10" of vacuum without starving the wrist pin of oil, and 10" will get you exactly 10 and 10 on both Torque and BHP, so its a nice little performance gain as well as controlling the oiling system.
Cheer's,
Mark.
Last edited by KiwiKid; 01-04-2015 at 05:56 PM.
Trending Topics
01-05-2015, 03:39 AM
#9
01-05-2015, 03:28 PM
#12
We run the New Zealand designed and built LINK, ECU, with MAF.
All the ECU's are locked, and tightly controlled by one individual.
A lot of time has been put into mapping the engine to deal with the Fly By Wire throttle, and whilst that is much better these day's its probably going to get junked in favour of a cable operated throttle in the near future.
01-05-2015, 03:40 PM
#13
OK, so thats what happened, I couldn't figure out how it the post got moved until I read your post.
Sorry about posting it in the wrong Generation, anyway all good.
Thanks,
Mark.
01-05-2015, 07:18 PM
#14
Great post! In my LS7 I swapped out the rods/pistons yet retained the stock pump with a 3 gallon Peterson oil tank. I found above 5000rpm the oil pressure wouldn't increase. Upon further research I read it was either cavitating or the plate on the pump was distorting and literally allowing oil to spray out and therefore not be able to build more pressure. The solution from a few experts was an LS9 pump with billet front plate from Katech and/or the Aviad route. I opted to sell the motor after crunching the cost for the bandaid and bought a motor with the Dailey billet dry sump.
It is nice having 400ft/lbs tq+ anywhere in the powerband.
How well are the Quaiffe sequential boxes holding up?
It is nice having 400ft/lbs tq+ anywhere in the powerband.
How well are the Quaiffe sequential boxes holding up?
01-05-2015, 11:56 PM
#15
Great post! In my LS7 I swapped out the rods/pistons yet retained the stock pump with a 3 gallon Peterson oil tank. I found above 5000rpm the oil pressure wouldn't increase. Upon further research I read it was either cavitating or the plate on the pump was distorting and literally allowing oil to spray out and therefore not be able to build more pressure. The solution from a few experts was an LS9 pump with billet front plate from Katech and/or the Aviad route. I opted to sell the motor after crunching the cost for the bandaid and bought a motor with the Dailey billet dry sump.
It is nice having 400ft/lbs tq+ anywhere in the powerband.
How well are the Quaiffe sequential boxes holding up?
It is nice having 400ft/lbs tq+ anywhere in the powerband.
How well are the Quaiffe sequential boxes holding up?
IMO, Bill's gear is the best in the business, I have used his pumps for several different application, which is why I worked with him to design a unique pump and pan to suit our V8ST application. I also commissioned him to design the small oil filter billet housing that he nows sell on his website.
I had to do a lot of talking to get him across the line on the small oil filter project but the fact is that up to at least 7,500 PRM thats all the oil system needs, and he finally agreed and made me what we wanted. Nice, neat and compact.
Regarding the 69G 6 speed Quaife sequential transmission, we had a huge amount of issue's with the gearboxes, particularly after we went to the Flat-shift system. It took a lot of very hard talking amid veiled threats of legal action for Quaife to finally agree to change their standard EN36b gear steel to EN39b and CNC finish grind the gear tooth profiles.
Their first attempt was a disaster and we returned 24 complete gear set's, after they changed their hobbing process to pre-turberance profile's that provided the desire key hole shape at the bottom of the tooth and steeped up their QC process they started delivering good parts.
We also had them change some other thing's that have made the transmission a very much better unit. We also do a mod to the gear change lever to stop that deflecting as it contact's the pin on the barrel, but we do that here in NZ its not a big deal but its well worth doing.
The biggest problem any transmission will have behind the standard LS7 engine, in Road Racing is the excessive driveline shock by product of the engines torque curve that the standard Camshaft delivers. Ideally we, V8ST, should have gone to GM's stage 2 camshaft which has a much better torque curve even though the peak torque and horsepower also increase's. However, there is an understandable resistance to constant change in such a controlled spec category, so I don't think that will happen any time soon.
01-08-2015, 09:54 PM
#17
Managing the torque on a big cube engine like the Ls7 is they key to drive-line reliability, which is one of the reason's why I am opting to de-stroke my Mosler's Ls7 engine and buzz it rather than shifting on the torque curve.
Bigger bore [4.185"] and less stroke [3.625"] will reduce my peak torque down to about 550 Ft lb's but raise my potential horsepower by as much as 200 BHP at 8,000RPM.
01-20-2015, 09:37 AM
#18
Teching In
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Thanks for sharing the invaluable information, Kiwikid!
So if I understand this correctly, you're saying that all things equal, the OEM setup can rev out to 7500 RPM's with just the single stage Aviaid scavenge pump?
Thanks.
So if I understand this correctly, you're saying that all things equal, the OEM setup can rev out to 7500 RPM's with just the single stage Aviaid scavenge pump?
Thanks.
01-20-2015, 10:41 AM
#19
Obviously with a change of cam, spring's etc, otherwise there is little point in revving beyond 6,500 rpm.
