boost dropping ?
10-09-2007, 12:21 PM
#61
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I think Stevie has some tired springs or something got messed up when he was wrenching on the car.
On that other tangent, since Stevie is not running BS3, my tuner has my timing at around 19 degrees, and the car made 867rwhp (has made 752rwhp on the same dyno with the old blower setup). But I am 8:1 so I while I don't plan to change the WOT tune I am curious as to how folks set up their timing, so I can learn.
On that other tangent, since Stevie is not running BS3, my tuner has my timing at around 19 degrees, and the car made 867rwhp (has made 752rwhp on the same dyno with the old blower setup). But I am 8:1 so I while I don't plan to change the WOT tune I am curious as to how folks set up their timing, so I can learn.
10-09-2007, 12:31 PM
#62
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Cam timing can cuase this so can excessive back pressure in the headers pre turbo.
Boost leak test done as far as the TB.
One leak detected, and sorted ( pre IC clamp not tight enough )
However, boost patterns remain pretty much the same. It seems to hit 18psi circa 6200rpm, but circa 6300rpm, boost always drops, and sort of flatlines at say 13-14psi
It will not regain boost, although the car will continue to accelerate to 7000rpm ( 4th gear runs )
Engine also feels pretty crap at that point.
Could it be valve float/bounce ? or lifters pumping up a bit ?
One leak detected, and sorted ( pre IC clamp not tight enough )
However, boost patterns remain pretty much the same. It seems to hit 18psi circa 6200rpm, but circa 6300rpm, boost always drops, and sort of flatlines at say 13-14psi
It will not regain boost, although the car will continue to accelerate to 7000rpm ( 4th gear runs )
Engine also feels pretty crap at that point.
Could it be valve float/bounce ? or lifters pumping up a bit ?
10-09-2007, 12:35 PM
#63
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I think Stevie has some tired springs or something got messed up when he was wrenching on the car.
On that other tangent, since Stevie is not running BS3, my tuner has my timing at around 19 degrees, and the car made 867rwhp (has made 752rwhp on the same dyno with the old blower setup). But I am 8:1 so I while I don't plan to change the WOT tune I am curious as to how folks set up their timing, so I can learn.
On that other tangent, since Stevie is not running BS3, my tuner has my timing at around 19 degrees, and the car made 867rwhp (has made 752rwhp on the same dyno with the old blower setup). But I am 8:1 so I while I don't plan to change the WOT tune I am curious as to how folks set up their timing, so I can learn.
Base timing around 15 degrees from 0 to 4800rpm to get past peak torque where cyl pressure should be the highest...then I ramp up to 18 degrees at 6000rpm and above...all at 18psi of boost max....then if I keep blowing the radials off I reduce the timing down low a couple of degrees to pull the torque back....then I keep an eye on the logs since I want ZERO kr...to me kr is a head gasket eater....my comp is 8.5 : 1
BTW I am running a spool as a posi wouldn't be a posi long in my car. Weight is a posi killer.
10-09-2007, 01:09 PM
#66
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Thread Starter
Im here....Im just a few hours ahead of you guys lol and only home from work.
Updates are typical of situations like this.
Im waiting on damn parts from the US !!!!! Im always bloody waiting !!
This hasnt happened all of a sudden, but has gradually been getting worse, although when I went from 382 to 346, it did become more marked. After stripping that engine, and the valves werent sealing properly, I put the problems down to that alone. I had no way to measure seat pressure at that time though. But when you buy brand new heads, and they have only 10k on them, you ( well I ) just assume they are fine.
I had hoped that with new lifters, correct pre-load, and a freshly built engine ( now 383 ) that my problems would have went away.
I have been informed, the springs etc are Patriots Gold's
So at present, Im waiting on some shims, which will allow me to add 90thou to the seat. Richard has been extremely helpful in this respect, and AFAIK these are on their way to me now, as well as some PR's so I can also try the 1.75 Jesels. He also sourced me a set of stock rockers to try too.
Ive also pm'd a couple of guys on this forum, about springs. One being Cary at ET, and the other some guy who seems to be from PAC ( I searched, and found these guys mentioning springs etc )
Not surprisingly, I have received no response as yet.....( back to the waiting thing again ).
If I can get someone to sell me some stiffer springs that will fit, I think I might prefer to do that. Wait wait wait......a reccurring theme
Exhaust is fine, car is always garaged, and I only have a pair of MagnaFlow stainless mufflers, which are straight through. So I dont think there is anyone/thing living in there at the minute....cant guarantee it tho !
Ign timing....must actually check this. I did fit/upgrade to a new ecu earlier in the year, but I see no reason why anything should change with regards to timing. Ive switched from old to new and back a few times due to initial teething problems with the new ecu, and the car drove the same.
Believe me, as soon as some parts arrive and I can get them fitted, I will have a proper update. I will probably only get one more chance this year ( weather permitting ) to get to a track again, and I really need to get that 9/150.
Which I think will come fairly easy if I can get my power/rpm's back.
The 10.32 at 142 I ran the other weekend, really felt crap. Car would not rev at all. So I know it has a lot more in it
Updates are typical of situations like this.
Im waiting on damn parts from the US !!!!! Im always bloody waiting !!
This hasnt happened all of a sudden, but has gradually been getting worse, although when I went from 382 to 346, it did become more marked. After stripping that engine, and the valves werent sealing properly, I put the problems down to that alone. I had no way to measure seat pressure at that time though. But when you buy brand new heads, and they have only 10k on them, you ( well I ) just assume they are fine.
I had hoped that with new lifters, correct pre-load, and a freshly built engine ( now 383 ) that my problems would have went away.
I have been informed, the springs etc are Patriots Gold's
So at present, Im waiting on some shims, which will allow me to add 90thou to the seat. Richard has been extremely helpful in this respect, and AFAIK these are on their way to me now, as well as some PR's so I can also try the 1.75 Jesels. He also sourced me a set of stock rockers to try too.
Ive also pm'd a couple of guys on this forum, about springs. One being Cary at ET, and the other some guy who seems to be from PAC ( I searched, and found these guys mentioning springs etc )
Not surprisingly, I have received no response as yet.....( back to the waiting thing again ).
If I can get someone to sell me some stiffer springs that will fit, I think I might prefer to do that. Wait wait wait......a reccurring theme
Exhaust is fine, car is always garaged, and I only have a pair of MagnaFlow stainless mufflers, which are straight through. So I dont think there is anyone/thing living in there at the minute....cant guarantee it tho !
Ign timing....must actually check this. I did fit/upgrade to a new ecu earlier in the year, but I see no reason why anything should change with regards to timing. Ive switched from old to new and back a few times due to initial teething problems with the new ecu, and the car drove the same.
Believe me, as soon as some parts arrive and I can get them fitted, I will have a proper update. I will probably only get one more chance this year ( weather permitting ) to get to a track again, and I really need to get that 9/150.
Which I think will come fairly easy if I can get my power/rpm's back.
The 10.32 at 142 I ran the other weekend, really felt crap. Car would not rev at all. So I know it has a lot more in it
10-09-2007, 01:53 PM
#67
LS1Tech Co-Founder
iTrader: (34)
This hasnt happened all of a sudden, but has gradually been getting worse, although when I went from 382 to 346, it did become more marked. After stripping that engine, and the valves werent sealing properly, I put the problems down to that alone. I had no way to measure seat pressure at that time though. But when you buy brand new heads, and they have only 10k on them, you ( well I ) just assume they are fine.
10-09-2007, 02:26 PM
#68
9 Second Club
Thread Starter
As I say, I have pm'd 2 potential sellers of springs here a couple of days ago, and have got no response.
I have now also enquired with WCCH too, to see what they can suggest, although the shims etc are on their way now. I probably wont see them until Monday though. Overnight delivery just doesnt happen
I really dont care what I have to do to get this fixed....but I need to find someone who will properly advise me of what I can use, and then actually sell me the stuff !!
I'll buy springs, rockers, pushrods, whatever !!! it doesnt bother me at the minute, I just want the damn thing sorted !!, and spares are always handy to have when you are a few thousand miles away from parts stockists.
Ive said it many times, but buying parts like this isnt always easy.
Ive just emailed another seller......
Wait wait wait.
I have now also enquired with WCCH too, to see what they can suggest, although the shims etc are on their way now. I probably wont see them until Monday though. Overnight delivery just doesnt happen
I really dont care what I have to do to get this fixed....but I need to find someone who will properly advise me of what I can use, and then actually sell me the stuff !!
I'll buy springs, rockers, pushrods, whatever !!! it doesnt bother me at the minute, I just want the damn thing sorted !!, and spares are always handy to have when you are a few thousand miles away from parts stockists.
Ive said it many times, but buying parts like this isnt always easy.
Ive just emailed another seller......
Wait wait wait.
10-09-2007, 03:44 PM
#69
Putting those 1.75 Jesels on there will most likely amplify the problem if its valve spring related. Best to slap the stock rockers on and give it a go.
I'm sure someone will sell you a set of springs if you keep trying, I can understand the frustration since i used to work on a lot of older exotic European cars and it was the same getting parts in the US.
I ran a cam similar to yours with the 918 style single PSI springs well over 7000 with no issues, its not like you are running some giant oddball cam.
I'm sure someone will sell you a set of springs if you keep trying, I can understand the frustration since i used to work on a lot of older exotic European cars and it was the same getting parts in the US.
I ran a cam similar to yours with the 918 style single PSI springs well over 7000 with no issues, its not like you are running some giant oddball cam.
10-09-2007, 03:51 PM
#70
9 Second Club
Thread Starter
I know that about the rockers....i do want to try a set of stock rockers first of all, as well as sorting seat pressure to something more suitable.
It was mentioned, the type of tester I used, arent that reliable, and a proper test should be conducted on the spring....
I'll ask around here and see if I can get someone to test the spring properly locally, just for a 2nd opinion. Although it doesnt matter now, I want them changed if I can.
Although IMO, even if they arent accurate, I was probably being kind to them saying they open at 100psi. Its actually slightly less.
Accurate or not, thats far far far too low.
It was mentioned, the type of tester I used, arent that reliable, and a proper test should be conducted on the spring....
I'll ask around here and see if I can get someone to test the spring properly locally, just for a 2nd opinion. Although it doesnt matter now, I want them changed if I can.
Although IMO, even if they arent accurate, I was probably being kind to them saying they open at 100psi. Its actually slightly less.
Accurate or not, thats far far far too low.
10-09-2007, 04:01 PM
#71
Those small hydraulic spring testers arent that bad really if you are in the right range. Make sure and check with the retainer on naturally. I have a couple of those and still use them at home. Its no 2000.00 valve spring tester for sure, but of course its way easier to replace the springs then buy a good spring tester 
10-20-2007, 03:18 PM
#75
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Theoritically its possiable that the belt could just be slipping. More RPM more Cubes more airflow = more opotunity for belt slip. I have seen that happen before. Up the cubes up the puley to compensate and boost problems get worse. The fact that its getting worse with RPM suggests that this may be exactly whats going on.
I am not really thinking valve spring issues. Although enough is not known about the camshaft ,intake valve wieght, rocker system, lifter condition,oil pressure etc.
I am not really thinking valve spring issues. Although enough is not known about the camshaft ,intake valve wieght, rocker system, lifter condition,oil pressure etc.
10-20-2007, 04:41 PM
#76
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Thread Starter
Intake valves are REV...2.055", 1.6", again, nothing out of the ordinary.
Rockers...1.7 YT's ( STILL
)Lifters...new Morels.
Oil pressure, dont know numbers, but whatever is typical of an LSx motor. The gauge in my car does not have numbers on it.
I will update this much, as I have got it running again this evening.
I have shimmed the springs to regain some seat pressure. Yet another DIY job in very respect, as the shims that were supposed to be here at the start of the week, havent even left the US yet
( along with the stock rockers I was waiting on to try )So I made some shims of my own lol
I think they should work ok though. Unless 2mm aluminium sheet and a hole saw isnt the ideal way to go about it ? Dont care. Im going racing next week one way or another, as its probably the last chance i'll get this year.Not sure if it will skew any results, but I also added a pair of Moroso Spiral flow mufflers in the centre section of my exhaust, to try and quieten things down a little.
I can now say, that boost is definately improved. During a 4th gear run.
15psi at 5000rpm
18.3psi at 6000rpm
21psi at 6500rpm
circa 23psi at 7000rpm
Although at 7000rpm, the boost is fluctuating a bit, and the engine still doesnt like it up there.
Slip or spring issues....not sure.
But car defo feels better than it did.
10-20-2007, 04:49 PM
#77
Glad to see you're making progress. Those aluminum shims will need to be checked - I think they'll get chewed through pretty quick with steel springs sitting on them.
Hey, did the 2nd set of mufflers help with the noise?
Jim
Hey, did the 2nd set of mufflers help with the noise?
Jim
10-20-2007, 05:05 PM
#78
9 Second Club
Thread Starter
Re shims. The springs are still sitting on their steel seats. my DIY shims are underneath this. SO I dont see it as being that much different to the spring seat sitting on the almunium head.
Re the mufflers.
A little, but only a little. The most annoying thing, as around 70mph when cruising, its very drony. Very annoying when driving a few hundred miles to the track.
It is defo improved, but still loud. Still need to sort some clearance issues with them though, as they do touch the body every now and again. Ive so little room
Re the mufflers.
A little, but only a little. The most annoying thing, as around 70mph when cruising, its very drony. Very annoying when driving a few hundred miles to the track.
It is defo improved, but still loud. Still need to sort some clearance issues with them though, as they do touch the body every now and again. Ive so little room
10-20-2007, 07:16 PM
#79
Try putting a couple strips of header wrap between them and the body. Makes a good hi-temp damper.
Yeah, the aluminum under the steel is way better, but still keep an eye out for wear - at the very least they will look burnished after a thousand miles - those shims jump around much more than people think.
I'm trying to catch up to your sick performance level - building a Motown block based 434 and will run the T-trim on that. I'll post some pix in the next couple weeks.
Jim
Yeah, the aluminum under the steel is way better, but still keep an eye out for wear - at the very least they will look burnished after a thousand miles - those shims jump around much more than people think.
I'm trying to catch up to your sick performance level - building a Motown block based 434 and will run the T-trim on that. I'll post some pix in the next couple weeks.
Jim
10-20-2007, 07:21 PM
#80
9 Second Club
Thread Starter
I guess they must do.....
https://ls1tech.com/forums/generation-iii-internal-engine/801402-spring-seats-breaking.html
I have all the good luck
https://ls1tech.com/forums/generation-iii-internal-engine/801402-spring-seats-breaking.html
I have all the good luck