Tony Mamo @ AFR
05-17-2007, 01:40 PM
Guys....
Awhile back I started a thread and posted engine dyno results concerning a 403 LS2 engine I built for Roy and Laura Vincent destined to be installed in their 04' GTO.
It was a mild build-up but one that focused on hitting all the details. Essentially Roy gave me the latitude to build this as if it were my own, and as most of you know I strive to put up big numbers in milder, more user friendly packages.
Here is a link to the original thread....some of the graghs and pics need to be re-hosted but I will work on that over the next day or two.
http://www.ls1tech.com/forums/showthread.php?t=649674&page=1
The chassis dyno results certainly back up the numbers we saw on the engine dyno back in February. In fact I told Roy I was hoping for 475-480 RWHP not knowing how efficient the converter and rest of the package would be. As the headline of the thread has already given away we did even better after the smoke cleared.
All of the chassis dyno work and tuning needs to be credited to Lance Viscioni who is the owner of Val's Performance, a shop some 50 miles outside of Chicago and close to Roy and Laura's home. I know Lance worked very hard to try an optimize a package he was excited to work with after seeing all the engine dyno information Roy had provided him with.
Here is the final gragh....it certainly is a good looking power curve.
http://www.lifeinwidescreen.com/siihp/Roys 403 Chassis Dyno.jpg
A few things to note....These results were thru a brand new level five 4L65 transmission (which Im sure robs a little more power than a conventional 4L60), aftermarket 3.90 gears, and the 3600 stall converter. As most of you know all of these mods help detract from "hero" numbers on the chassis dyno. Roy and I have discussed a tighter more efficient converter because this combination has so much low speed grunt its probably more than he needs. Lance says first gear is practically useless and he spends less than a second there at WOT (right from the datalog). The trans cant shift as fast as the engine wants to accelerate in the lower gears occasionally hitting the 7K rev limiter even though Lance is commanding a 6500 RPM shiftpoint. IMO, with the immediate TQ this combination provides a 2800 stall would have been more than adequate and might have worked better, especially for a car that will see most of its cruising on the street, not the dragstrip.
These numbers were also recorded thru cats and his factory exhaust but utilizing electric cutout's between the cats and mufflers. We had considered dropping the cats to see if we could get closer to the magical 500 mark, but knowing Roy would never run the car that way decided to spend more time optimizing the combo with the cats in place.
Also worthy of mention is how well the combo carries power in spite of a "small" 205 cc intake runner, 1.75" headers, and a small cam on a larger displacement build...in some respects it goes against conventional wisdom and shows you what the right package as a whole is capable of.
These numbers were recorded using a DynoJet 224 inertia dyno and of course the converter was locked during all the testing.
Lance says the car has a very stealthy idle and drives like stock....just has gobs of low speed TQ, insane throttle response, and simply explodes when you go WOT....traction is a major issue.
I am trying to get a sound clip of it and might be able to make that happen over the next few days.
Just thought I would pass all this info along....while this combination is admitedly expensive to duplicate.....the real world results might justify the added expense for some of the more conservative folks out there. It's pretty close to having your cake and eating it to as I know of very few A4 cars (with similar displacement) making this much power regardless of good or bad street manners.
Congrats Roy and Laura....its been a long road but a very worthwhile journey to say the least
Cheers,
Tony M.
Awhile back I started a thread and posted engine dyno results concerning a 403 LS2 engine I built for Roy and Laura Vincent destined to be installed in their 04' GTO.
It was a mild build-up but one that focused on hitting all the details. Essentially Roy gave me the latitude to build this as if it were my own, and as most of you know I strive to put up big numbers in milder, more user friendly packages.
Here is a link to the original thread....some of the graghs and pics need to be re-hosted but I will work on that over the next day or two.
http://www.ls1tech.com/forums/showthread.php?t=649674&page=1
The chassis dyno results certainly back up the numbers we saw on the engine dyno back in February. In fact I told Roy I was hoping for 475-480 RWHP not knowing how efficient the converter and rest of the package would be. As the headline of the thread has already given away we did even better after the smoke cleared.
All of the chassis dyno work and tuning needs to be credited to Lance Viscioni who is the owner of Val's Performance, a shop some 50 miles outside of Chicago and close to Roy and Laura's home. I know Lance worked very hard to try an optimize a package he was excited to work with after seeing all the engine dyno information Roy had provided him with.
Here is the final gragh....it certainly is a good looking power curve.
http://www.lifeinwidescreen.com/siihp/Roys 403 Chassis Dyno.jpg
A few things to note....These results were thru a brand new level five 4L65 transmission (which Im sure robs a little more power than a conventional 4L60), aftermarket 3.90 gears, and the 3600 stall converter. As most of you know all of these mods help detract from "hero" numbers on the chassis dyno. Roy and I have discussed a tighter more efficient converter because this combination has so much low speed grunt its probably more than he needs. Lance says first gear is practically useless and he spends less than a second there at WOT (right from the datalog). The trans cant shift as fast as the engine wants to accelerate in the lower gears occasionally hitting the 7K rev limiter even though Lance is commanding a 6500 RPM shiftpoint. IMO, with the immediate TQ this combination provides a 2800 stall would have been more than adequate and might have worked better, especially for a car that will see most of its cruising on the street, not the dragstrip.
These numbers were also recorded thru cats and his factory exhaust but utilizing electric cutout's between the cats and mufflers. We had considered dropping the cats to see if we could get closer to the magical 500 mark, but knowing Roy would never run the car that way decided to spend more time optimizing the combo with the cats in place.
Also worthy of mention is how well the combo carries power in spite of a "small" 205 cc intake runner, 1.75" headers, and a small cam on a larger displacement build...in some respects it goes against conventional wisdom and shows you what the right package as a whole is capable of.
These numbers were recorded using a DynoJet 224 inertia dyno and of course the converter was locked during all the testing.
Lance says the car has a very stealthy idle and drives like stock....just has gobs of low speed TQ, insane throttle response, and simply explodes when you go WOT....traction is a major issue.
I am trying to get a sound clip of it and might be able to make that happen over the next few days.
Just thought I would pass all this info along....while this combination is admitedly expensive to duplicate.....the real world results might justify the added expense for some of the more conservative folks out there. It's pretty close to having your cake and eating it to as I know of very few A4 cars (with similar displacement) making this much power regardless of good or bad street manners.
Congrats Roy and Laura....its been a long road but a very worthwhile journey to say the least
Cheers,
Tony M.