Dyno Results Low on Modded 05 GTO

**GoatRider** · 10-10-2006, 10:45 PM

Yesterday I was expecting high dyno results (360 HP/TQ) but actual results were (331 HP and 323 TQ). The test was performed on a Dyno Jet. My 05 GTO A4 was dyno tuned for the first time. Mileage is better now than before the tune. Air fuel ratio was constant at about 12.8 throughout the rpm range.

If my car was stock, I could accept the results better. But the car has a K & N cold air induction, JBA headers with JBA high-flow catted midpipe, GHL catback exhaust and 160 degree thermostat.

The midpipe, thermostat and oil change were done a few hours before the dyno tune was made. The headers, CAI and catback were installed several months ago.

There was a problem with the radiator coolant leaking out during the thermostat change. The lost coolant wasn't replaced, but the temp gauge still read a little lower than usual even with the lost coolant. However, the tuner did say that he could only advance the timing by 1% due to detonation. The air temparature was about 87 degrees at 6PM Arizona time.

My guess is there must be a problem with the engine that I don't know about. Otherwise, the HP/TQ results would have been higher. What do you think? Does 331 HP and 323 TQ for a modded and dyno tuned 05 GTO sound right to you?

If my Goat got an LS1 engine in it instead of an LS2 engine, then the numbers might add up. How can I know for sure that my car has an LS2 engine without going to the expense of measuring the bore and stroke? That is the only rational explaination I can thing of for the low HP/TQ results.

**Sarge** · 10-11-2006, 03:43 AM

Few things...LOL.....If you have a 05 you got a LS2....
I hate dyno's....there are so many variables that impact "numbers".....but lets assume the tuner/operator has had that dyno calibrated by a certified calibration tech recently.....so many of those things are all out of whack it is ridiculous....
If your ride was being dyno'd while sitting there at operating temp you probably were experiancing heat soak which would make your numbers right on the mark......I would relocate your IAT for sure.....big difference....
http://www.ls1.com/forums/showthread...&highlight=iat
Ask your tuner what the IAT temp readings were when you dyno's it....
2ndly....And I'm not attacking your tuner here....but....many tuners out there are not up to speed on the ls2's....ls1's and 2's are way different animals...the tables are all different.....
12.8 throughout the rpm range is a little on the rich side....OK at WOT but throughout has me confused why he would tune it that way....
I'm at 15.2 at idle or cruising speeds....low 12's high 11's at WOT only...
Bottom line here is.... I dont believe your lower numbers are indicative of an Engine problem.....but directly related to the variables of IAT temps/Tuner/Dyno calibration.....with a proper LS2 tune ( aint knocking your guy just I would get a 2nd opinion.....(AZ Power and Sound turns out some really good tunes....are you using them by any chance?) or send me your dyno sheet and I'll have a local guru take a look and share his comments.....

**Rob** · 10-11-2006, 06:41 AM

A4's typically don't dyno all that well compared to M6's. Sounds like its tuned fairly well, at least air/fuel, just a hair rich but its safe. Take it to the track and see what it does. I'm betting the real HP numbers will be better than those dyno numbers.

**GoatRider** · 10-11-2006, 11:46 AM

Thanks Sarge and Bob for the replies. I called an auto diagnostic shop and they suggested doing a leak-down test. If my Goat fails this test, what should I do? The test is scheduled on Oct 17. What is a leak-down test?

**GoatRider** · 10-11-2006, 11:48 AM

Correction: Thanks Sarge and Rob...

**Sarge** · 10-11-2006, 04:49 PM

Originally Posted by GoatRider

Thanks Sarge and Bob for the replies. I called an auto diagnostic shop and they suggested doing a leak-down test. If my Goat fails this test, what should I do? The test is scheduled on Oct 17. What is a leak-down test?

They are wanting to check compression in your cylinders...this is bullshit////
Who or what shop are you using?...a leakdown test?! Bullshit....they are clueless..We have a stock 05 A4 in the shop getting a ProCharger right now that put down 360 to the wheels.....Answer my questions in my first response or I cannot help you...leakdown test my ass....

**goat-ee** · 10-11-2006, 08:47 PM

My opinion...you don't have mods. JBA shorties do nothing for performance, the midpipe and catback together 10hp max. The Hot air K & N is doing almost nothing. And of course the always wonderful 160* thermostat does nothing. You need to do more research on your mods, and try a different tuner. There is nothing wrong with the numbers, sounds pretty close for an A4 to me with your "mods". 410 flywheel horse minus 20% for an automatic and you would be at 328 hp at the wheels. Pretty damn close to what you got.

DO NOT pay for a leakdown test. I am not trying to sound mean, but from your original post it's clear you don't know a whole lot about your car and you have some guys ready to take advantage of that fact. If these guys are ready to tell you that you need a leakdown test, they are just trying to rob you. Do a bunch more research than you have. Do some better mods and THEN if you want a tune, find someone that you can trust. Ask the guys on this board or on www.dynoqueeninternetexperts.com for advise and a referral to a good tuner.

**johnebgoode** · 10-13-2006, 02:37 PM

Why not take it to the track and see what it posts. You'll be surprised I bet. My 05 A4 has a tune,(without dyno), K&N CAI and an SLP LM II. ran a best 12.96 @ 109.+ with a 1.94 60' on street tires. Dont make yourself nuts till ya get a time slip.

**Sarge** · 10-13-2006, 04:47 PM

Sub 2's 60'/ cool

**GoatRider** · 10-16-2006, 06:42 PM

Hi Sarge! I didn't get the leak-down test as you recommended. I have been reluctant to answer your question about who did the tune up because I don't want a negative light to shine on the tuner. But I will say that the tuner has a good reputation in AZ. I actually had two dyno tests done.

The first one was done on April 3rd using the same dyno jet machine. However, I can't remember if I was running 98 octane at that time or not. The mods were the same except for no tune up, no high flow converters and no 160 degree thermostat. The numbers are as follows:

First dyno run 4/3/06: HP 333, TQ 338, Octane 98?
Second dyno run 10/9/06: HP 331, TQ 323, Octane 91

The stange thing about these low numbers is that the car runs and sounds like it has 450 HP. I can't figure out these dyno numbers. If you want, I could mail or fax the dyno results to you.

But I was calculating that BHP should be about 450 for this reason:

JBA claims 25 to 30 hp to the wheels.
K&N CAI claims 14 hp.
Catback is good for what 5 hp?
Catted midpipes are good for 2 hp?

Add these numbers and it should be about 450 BHP. If 450 BHP is correct, is it possible to be losing 119 HP (450-331) to the rear wheels?

txcosmos · 10-17-2006, 06:04 AM

You are going to lose about 18% of your horsepower through various areas of the car just because it's an A4. So, on a 400 HP car, your dyno should be showing around 328 stock.

K&N isn't going to do a whole lot, but it should give up something with the headers, even if they are JBA's. The catback and pipes aren't gonna do much either, and the 160 stat isn't gonna show numbers either.

The tune should have opened up something, especially with some type of intake and header though.

I think you are a little low on the dyno numbers, but remember, if you go down the street to another shop, it might read 420 on their dyno. If the car is running good and strong, don't worry about the dyno numbers, just use them as a starting point to determine the gains from certain mods.

Or, if you really think that there is a problem, don't hesitate to let another tuner look at the car. I'm on my 3rd tuner, not all of them know what they are doing.

**ramrod** · 10-17-2006, 07:57 AM

Originally Posted by Sarge

They are wanting to check compression in your cylinders...this is bullshit////
Who or what shop are you using?...a leakdown test?! Bullshit....they are clueless..We have a stock 05 A4 in the shop getting a ProCharger right now that put down 360 to the wheels.....Answer my questions in my first response or I cannot help you...leakdown test my ass....

Sounds like a buch of money hungry fools who don't know tuning worth shit!!