I had my car tuned with the 3.12 pulley by Ralph @ CP Racing back in Sept. of last year and I was very pleased with the outcome... 367RWHP and 305RWTQ. I have noticed that my 4th gear has considerably less pull than gears 1-3. When I am on the drag strip, the car pulls hard thru 1, 2 & 3, but when I shift into 4th, its a totally different ballgame. The pull that was present in earlier gears is no longer there and I feel that that is hurting my 1/4 mile times as well as my overall performance from a roll.

When Ralph tuned my car, I believe he tuned it in 2nd or 3rd. I know for a fact that it WAS NOT tuned in 4th. I did notice that my highest dyno run during tuning was done in 4th though. Could it be possible that this is the reason for 4th gear being as "weak" as it seems? In other words, could a retune cause me to get more power both under the curve and peak?

 

If your tuned in 3rd your 4th should be the same....I do agree your traps are very low for your whp, have you ever considered dyoing on a dynojet and checking the numbers elsewhere? Judging by your 1/4 times and def your trap I don think your making 360+whp. <----not a put down at all man, Im being serious.

 

I had dynoed on 2 different Dynojet dynos before going to CPR. I dynoed at Walker Dynotune in Trussville, AL and got around 340RWHP and then I went to Z1 Motorsports in GA and hit around 310-315RWHP. I have heard from numerous people that Z1's dyno reads low. These numbers were with the 3.33 pulley. Then I went to CPR and and had the 3.12 pulley installed and put down 367RWHP on their dynodynamics dyno or whatever it is called.

This car has always had really screwed up numbers. I dynoed with headers, TP, Injen exhaust, plenum, and the Popcharger before going F/I and ONLY put down 232RWHP!! WAAAYYYY low for what I feel I should have been putting down.

Could the fact that my car loses the strength of its pull as soon as I shift into 4th be a reason for my low trap speed and lower 1/4 times than comparably equipped cars?

 

I had 350whp on a Mustang dyno and trapped 108mph . Sounds about right

 

4th is 1 to 1 on the 5AT. That's what's your suppose to dyno in. if you want a nice 4th gear get the 3.5 rearend. Feels like 3rd.

 

On a load base dyno...it doesnt matter what gear you dyno in

 

ahhhhh my bad, never been on one

 

Dont you have a G sedan though? 108 mph trap is way low for 350whp on any dyno, so I would say you rnot a very good example of what that power can do. Ive seen a 360whp auto Z trap 113mph.

zachrosen-what does redline in 3rd gear go to mph wise? What are your shift points?

 

I say get the 3.5 rear end, i had the same problem with the original pumpkin, but now, its all over

 

I do have the 3.5 pumpkin. That got my trap from 106 to 108.

 

I have a G35 coupe AT5 . My car with me in it is 3700lb's . And not all of us have our cars set up to drag them like you do . Ive only broke into the 12's once . Thats with a 1.98 60ft . and 12.98 1/4 mile .

Im sure now with 420whp I'll get into the lower 12's

 

Horsepower isn't the only thing that is needed to 'hit the 12's. but besides that, once you hit 1 to 1 ratio its usually all over.

 

I think the problem is with the gearing in the auto transmission itself. Even with the 3.5 FD, we are still short a gear. I did the math once and it actually drops off in 3rd gear. I think 3rd gear in an AT5 would only be comparable to 3rd gear in a MT6 if the AT5 had a 3.9 FD. But then 1,2 is too much and 5 would be more like 1 to 1.

As a side note, has anyone ever pressed the issue for a 3.7 FD? This might be what we need.

 

On the run I did 12.98 and with most runs I have done . I didnt shift to 4th . I used to be able to get to the line at 7100rpm and 108mph in 3rd gear

 

If I am not mistaken, Jason@performance can hook you up with a 3.7. I cant remember the cost, but search and you will find his info on the 3.7 he can get us. The key is that you already have the 3.5 pumpkin.

 

Thanks Zachrosen, I just found that thread. I have the 3.5 on the car and the 3.3 in the garage. I don't have any 1/4 mile times, but our 1/8 mile times look comparable. On street tires, I've run 8.3 @ 88. I am at 1900 ft elevation if that helps. (comparable HP/TQ #s)

Booger, are you talking about the 3.3 Fd when in 3rd?

 

Yes....I had the stocker in place when doing it . I now have the 3.5 in and havent been back to the track . In fact , the track closed and we only have a 1/8th mile now .

 

I take it you don't like the 1/8th? I have three 1/8 within an hour drive (30, 45, 60 min) and the closest 1/4 is like 3 hours away. Oh well.

 

Oh yeah and another 1/8 like 90 min away.

 

Is the 1/4 that is 3 hrs away in Commerce, GA by chance?