1997 SLP FIREHAWK LT4
February 17th, 2004: 311RWHP, 325.7TQ
Mods: Stock w/ custom ECM tune from MadZ28.com and LT4 Knock Module
Well, I finally got
around to getting another dyno done after fixing a couple of things on the car.
The first thing was putting in the LT4 Knock Module in place of the LT1 module
that came with the stock ECM. Once again I really don't understand why SLP
left the stock ECM (including knock module) in these cars when they put in the
LT4 engines, but it sure makes for a nice change when you "fix" it. I also
had been hearing a "ticking" at startup over the last month or so, and when I
finally got a chance to check it this past weekend I discovered a couple of
loose exhaust manifold bolts on the driver's side. I don't think the
exhaust manifold bolts were loose when I did the previous dyno, so at this point
I'm going to say that the big gain over last time (11RWHP and 8TQ) came from the
LT4 knock module. This would tend to hold up as I was seeing some knock
retard after the last dyno run when I did some monitoring using Datamaster.
After retightening the manifold bolts over the weekend I am now seeing ZERO
knock retard (both on the dyno and on the street). So, the final gain from
the ECM tuning and LT4 knock module at this point are:
29RWHP and 21TQ
This now puts flywheel HP at 366HP, and I'm hoping to increase it a little more as the car is still running a little rich (about 12:1-12.5:1), and by adding a few mods. My goal at this point is to get to 330RWHP so that the 330 HP stickers on the hood actually match up to something!
December 1st, 2003: 300RWHP, 317.4TQ
Mods: Stock w/ custom ECM tune from MadZ28.com
Now this is more like it! 300RWHP and 317.4lb-ft of torque and we still aren't finished tuning yet. A big thanks to Ion at MadZ28.com for the great tuning job. It's still running a little rich above 5600 and we think we can squeeze another 5-10HP out of it by the time it's optimized, of course it's also still got the LT1 knock module so this could be false knock too. I didn't have my monitoring software with me for the dyno run, so I'm not sure which it is. I'm really happy with these results since most LT4s in the 96 Corvettes were putting out right at 300RWHP stock and they have a better flowing exhaust than the Firehawk. This puts the flywheel HP at 355HP using a 15% driveline loss and is pretty impressive.
October 2nd, 2003: 280.8RWHP, 300.1TQ
1997 LT4 Firehawk, completely stock
Well, these results are somewhat dissapointing with peak numbers of 282HP and 305lb/ft of TQ, but the culprit for this is very obvious. If you'll notice the Air Fuel Ratio you'll see that it is sitting at 11 through most of the run and dropping to 10 and below above 5000rpm. This is WAY rich on fuel and is causing a major power loss. Optimum A/F for this car should probably be right around 13.5:1, so there should be somewhere around another 20HP just by leaning out the fuel tuning. Then I'd guess it'll pick up another 10HP with raising the rev limiter to the proper LT4 limit (6500rpm), so I'm hoping to hit right at 310HP to the wheels once I get the computer tuned properly. Also, I should probably pick up a few MPG by leaning out the A/F ratio as well, which would be good considering the car is only getting right at 17MPH right now on a 70/30 hwy/city driving loop. As to how this compares to the rated stock flywheel HP numbers, given a 16% driveline loss this would be 336HP. Considering SLP rated these cars at 330HP, they are right on the money.
2001 Chevrolet Corvette Z06 (LS6)
July 1st, 2003: 2001 Corvette Z06, Stock except for open air filter lid (zip tie mod), and no pup cats.
This is bone stock except for the removal of the air filter lid (still has paper filter element, just allows better flow into the filter), and removal of the 2001 pup (pre) cats. For 02-04 GM eliminated the pup cats and used a larger filter lid, so these two mods are basically matching those specs. The main catalytic converters are still in place and the car would still pass emissions inspection if the Oklahoma did them. I am very pleased with this result as it is as good or better than what many 02+ Z06s are dynoing. Using a conversion factor of 16% driveline loss, the flywheel HP (the ratings car manufacturers give and magazines quote) for this car would be 416HP. Not bad considering the car was rated from the factory for 385HP, and that 02-04 Z06s are rated at 405HP.
1992 Chevrolet Corvette (LT1)
March 22, 2002: 92 Corvette, Stock except for Muffler Eliminators and SLP chip
This is bone stock except for the removal of the stock mufflers which were replaced with straight pipes, and the addition of an SLP computer chip. The chip is actually probably hurting performance a little as the car seems to be running rich on the top end, but I got it mainly for turning the fans on at 200 degrees instead of 230.
1995 Pontiac Firebird Formula (LT1)
Here is the dyno from my 95 Formula. Dynorun.003 (the lowest) is stock with a K&N intake and cat-back. 004 is with the upgraded cam (214/214) and 1.6 roller rockers, while 011 also has custom ECM tuning. The max figures on it were 285.4RWHP and 319.1RWTQ.
2000 Pontiac Trans Am (LS1)
Tuesday 9/19/00: Bone Stock, absolutely no mods. 1750 miles.
Here's the dyno of the 2000 TA. 304.1 RWHP and 317.1 RWTQ. For those of you that aren't familiar with these ratings the RW stands for rear wheel, where the power actually gets put to the road. Definitely a great running engine, but that extra low end torque really makes a big difference in how the car feels. Also, with just a few minor mods the Vette should be putting out the same or better HP as the LS1.
1988 Porsche 944 Turbo S
March 13th, 2005: 276RWHP, 302TQ
Mods: Lindsey Dual Port Wastegate, SBC Electronic Boost Controller, Guru 18psi chips and 3 bar fuel pressure regulator
Still having having problems with overboost protection activating in 4th gear, so again we dynoed in 3rd. Of course, for comparison to previous runs this is better anyway. Obviously both HP and torque are way up from last time, you can also see that the boost hits much sooner and way harder. It's running a little lean on the top end, so I'm awaiting a revised tune. Between that and when I get the overboost solved and get a good 4th gear run, I'm hoping to see another 5-10HP. I think the overboost issue is related to one of three things: bad head gasket, bad airflow meter, or bad KLR (1 of 2 ECMs in the car). Since the head gasket just failed, I'm getting that fixed first, and then if I'm still having overboost issues in 4th gear, I'll try the other two possibilities.
February 12th, 2005: 223RWHP, 230TQ
Mods: Stock w/ Lindsey Dual Port Wastegate and Manual Boost Controller
Finally got a chance to get a baseline dyno done on the car. The weather really wasn't very good for a turbo car (100% humidity), and we were also having problems getting it to dyno in 4th (1:1 gear), so we ended up having to dyno in 3rd. It looks like with the aftermarket wastegate it was holding too much boost and the ECM was cutting power in 4th. Anyway, the figures definitely aren't too bad considering those factors (I'd guess there's another 10+ HP there alone). Since the car is rated at 250HP (212RWHP with a 15% driveline loss) stock, I think it's doing pretty good.