Fred O'Bannion

iTrader: (-1)

So I changed my gear from a 3.23 to a 3.73 and went to track and the car went slower. That was the only thing I changed.

With the 3.23's I went 12.60 @ 109 with a 1.87 60ft and with the 3.73's I could only get a 12.62 @ 110 with 1.86 60ft. Very strange.

One concern is that my car is only trapping @ 5200 RPM's. Shouldn't it be higher considering that I'm shifting @ 6500?

Any help appreciated.

SlickVert

iTrader: (5)

Weather maybe different.
Also, you should Auto Tap and Wide Band it as goes down the track, you maybe getting knock, not at correct air fuel, shift points, ect.
Track tuning will make a big difference.

Bob

Coach 02 A3 Z/28

iTrader: (10)

Weather plays a very big part.

Coach

RAGENZ28

iTrader: (5)

You have an auto with 3.73 with a 26" tire and you're only running 110 mph it's not going to rev to much more. 5200 rpm is about 108 mph without slippage, sounds right to me, so either add power, spray the car or go with more gear if you're not going to add power I would go at least 4.30's

PowershifterNC

what was it trapping with the other gear (rpm)?

Dragkid1917

iTrader: (2)

id say with that big cam to only be trapping 110 mph is a problem in itself.

Fred O'Bannion

iTrader: (-1)

It was trapping @ 5200 with the 3.23's. So really nothing changed. And I had 28" tall ET streets.

ta_06374

iTrader: (7)

Your killing yourself with that tire...

Camaro396

iTrader: (14)

Problem solved. Unless you had the 28" ET Streets before, adding a 3.73 gear, and that tire, pretty much knocks you right back down to having a 3.23 gear. Put a 26" tire on it and call it a day. Should run alot better. Also weather has a big play, my car back when it was stock has run between 13.20s-13.40s just on diffrent days with the weather.

01FbTaWs6

iTrader: (12)

holy hell man. no need for a 28 inch tire dude. Toss a 26 back on there and you will notice a hell of a difference.

Fred O'Bannion

iTrader: (-1)

yeah it must be the tire (and the weather). My brother reminded me that I had the 26" tire on the 12.60 pass. The only other time I ran a 28" tire was when I sprayed it with a 150 shot out of the hole and it ran an 11.55. No more spray with 3.73's though. I like to keep the rearend under the car for a while.

01FbTaWs6

iTrader: (12)

ah, ok. If you ran the 26 tall tire on motor, then Ide say you have problems. I trapped 110 with bolt ons. How is the tune???? 28 tall on spray would be perfect.

Fred O'Bannion

iTrader: (-1)

I see you have CNC ported LS6 heads, I'm about to put some on my car this week. I'm hoping to hit similiar numbers to what you ran on motor. I assume your car is an M6? If so what are leaving the line at?

quadd2244

iTrader: (13)

Yeah 12.60 at 109 with a big cam like that and a stall seems terrible. My trans am with a stock ls1intake still and stock heads,cam,3.23 gear out back traps 12.90s at 106 basicly

quadd2244

iTrader: (13)

All i have is Lts and a 3000stall

Where are you located as well

01FbTaWs6

iTrader: (12)

Yeah, its an M6, but your not going to pick up 7 mph with just heads man. That mph is through the full catback also, I bet i can get another 1-2 with a cutout.

Fred O'Bannion

iTrader: (-1)

i don't know...we would have similar mods once I add the heads. Or is there more to your car than what's in your sig?

And Houston

01FbTaWs6

iTrader: (12)

no man, just whats in the sig dude. But im telling you. I went 12.90 at 110 MPH with BOLT ON's ONLY.......... Thats what your running with a nice sized CAM. I went heads/cam and gained the 7 mph. added roughly 80-90 hp and gained 7 mph. Your not going to gain 7-8 mph from 35-40 hp.

Fred O'Bannion

iTrader: (-1)

Yeah I suppose 7 MPH is a bit much to ask with just the heads. I guess I will change the stall to a 3500 and have a better tune done on it and see what happens (and go back to 26" drag radials).

If that doesn't do it I will just spay the hell out of it and when it pops build a motor that will get me in the 11's.


Thanks for the imput.