Took my car down to Speed Productions in Jackson Mississippi to get a dyno run on it, I had been wanting to do this for awhile and when the chance came for 3 dyno runs for $50 I couldn't pass it up, so I brought my car down and had them run it.

My car is an A4 with 2.73's, mods are SLP LM1 cat-back, SLP lid, and Ported & Polished throttle body, nothing else.

The car put up some surprising numbers:

325.55 RWHP
347.43 RWTQ

Temperature in the garage was 99 degrees, humidity was 31%.

With an 18% drive train loss, which I think is standard for the 4 speed automatics, the car should be making 384.19 horsepower to the crank. Did a cat-back, lid, and TB really help to add 34HP to the car? Or was it a little bit higher than 350 to begin with do you think? People were impressed and thought it had to have heads or headers to be making those numbers.





Also, I apologize, but since I uploaded the video to YouTube it seems to be very quiet, you will probably have to turn up your volume to be able to hear it. Let me know what you guys think.

 

Very decent numbers. And 2.73s? lol

 

pretty good numbers considering the bolt ons on the car. dynojets usually read a bit higher than mustang dynos though right?

the car is an automatic. the 4l60e is a 700r4 so it has a super deep first gear in the trans. its more like having 3.30/3.40s in first gear so it doesnt really need gearing to come out of the hole. id still personally go with more gearing, but then again with that first gear in that trans its probably only a couple of bolt ons away from having an issue hooking on the street.

 

Yes, I was pretty pleased with them. The 2.73's came stock with the car, why is that funny?

 

That's what people are saying, they say a Mustang Dyno will bring me back down to earth, so maybe that means the TRUE power lies somewhere in the middle of each of them?

You obviously understand the 4l60e a lot better than I do, all I know is the car launches hard in 1st gear, but is a complete dog in most of 2nd and 3rd gear.

Have surprised more than a few people from a launch in 1st gear though.

 

Dynojets do always read a bit higher. On a mustang dyno expect about 290-300 ish.


And I laughed a bit because that is crazy gearing. With how cheap parts are for those I would have at least thrown in some stock 3.42s. That's why it feels so doggy in 2nd and 3rd, its because you have it under so much load.

 

Except that gears don't make it a lick faster in the 1/4 mile and don't translate to any more power at the dyno. Plus with 2.73's it's able to get 27MPG on the highway.

 

all dynos are different so i dont think theres really a good definite formula for what the car would make on another dyno. the true test would be to dyno the car on the same dyno after every mod, or the numbers are pretty much useless.

the 2.73s are the stock gears for the auto car. it has a deep first gear in the trans. the 4l60e is the electric 700r4. the stick cars had the 3.42s. the deep first makes it similar to the 3.42s in first.

i dont know what having the car under so much load means, or why it would make the car feel like a dog in 2nd or 3rd. it should be under load while shifting. you shouldnt lift at all, your foot should be through the floor going through the gears. the reason why it feels like a dog is because the 2nd gear in that trans is similar to the th350 1st gear. its like a 2.54 or something. its a huge drop from the 1st to 2nd shift. leaving the car low in the rpm range with no gearing to rev with. thats one of the multiple reasons why everyone dislikes the 700. they recently started making a new planetary for them to solve that problem(its crazy money). 3rd feels like a dog because thats the 1:1 gear, and once again the car has no gearing in the rear.


i couldnt really tell you much about dyno numbers other than the mustang dyno is the more accurate of the 2, and that theyre both just tuning tools. numbers are bragging rights and dont really give any indication of what the car will run, just what the car is capable of at its given weight if the planets align and everything goes right. ive seen cars that make less than 400rwp blow away dyno queens. a good drag car is a working combo. all the power in the world means nothing if the car blows the tires away, or worse wheel hops like crazy(ive had both). this is a moot point if you are of the modern era where we roll race or european 10mile. at that point the only thing that really matters is what car is lighter by a wide margin or makes more power. which in essence eliminates the point of running the car in the first place. in an auto car with a auto valve body from a roll the driver is essentially just a passenger, and as long as someone doesnt fast honk or youre not sleeping driver error is non existant(with a manual/auto valve body and a ****ty shifter this can be a completely different story). this seems to be a popular fad with stick, fwd, and power adder guys. most probably has to do with the inability to cleanly launch the car, and doesnt prove much about the car and driver combo(unless its a stick). the car with more money in it should win. this is why races should be run from a dig on the street, with the owner driving. its a true test of what the vehicle is actually capable of with the person that drives it in real life. this is only my opinion.

on the car feeling like a dog in 2nd and 3rd, but goin like hell in 1st i explained that above so no need for me to go into it again.

im sure its caught many people unawares, it happens, and from a slow roll im sure its tough. im sure its not as tough from a roll that puts you at the very top of 2nd.

ill agree with you that it wont make more horsepower with deeper gearing(i went into bragging rights and how much hp numbers matter above), but ill absolutely disagree about it not running a better time in the quarter. your car should go throw the traps at the very end of 3rd gear. i havent driven your car, but ill doubt that thats the case since we run a similar trans, and ill assume your motor can pull all the way to 6500 like mine. on a 28" tire, and 3.73s in the back i pull till the end of 3rd in the 6400 range(i speak of my 80 not the ls4). you certainly wont get 27mpg with the deeper gearing, and the car will be more difficult to launch cleanly, but it will definitely run a better time. like ive said before its all a compromise in this game. personally i would throw a little stall speed at that car, a little gearing(something in the mid 3s.), and some 305s out back and go hunting. youll lose a couple mpg, but itll make a big difference performance wise. dont forget your trans is an overdrive trans and will cut the rear gearing by 25% once you hit 4th(4th is a .75 gear i believe). so if your running 3.55s itll be like running 2.83s(ballpark figure). fuel mileage wouldnt suffer all that much, and the car will be more responsive in 2nd and 3rd. if the goal is to stay at 27mpg, than i would say work on suspension, get a convertor and buy a very short drag radial for the track, because the deeper you get into modifying the car the less fuel efficient itll eventually be(that is if it stays na of course).