Went to the track tonight got some good results I think. First of I have to change my gearing big time. I shift the car at 5400 first two runs I had to shift into 5th gear long before the traps so it runs low 13s @106. Well third run I decide to just let it scream in 4th gear and it goes 13.2@111.8mph I actualy went through the traps in 4th gear at over 6100 rpm long after my 5400 shift point 4th run I do the same leave it in 4th and let it scream to 6100 13.4@111mph blew the tires real bad. I didn't get to put my nittos on so all runs were done on a 275-45-17 yokahoma tires. I have no dought it would hit 115 easy with higher gears. I didn't make a 5th run cause I didn't like the idea of just reving almost a 1000rpm past my shift point or peak power.
Keep in mind the only mod to this L98 is a steath ram intake with a stock TB on it. Oh yeagh boost was between 8-9 pounds
I would like to run a little more boost but not sure what would be safe? My 93Z28 has the stock 3:23 10 bolt so I'am going to swap my 3:73 out of my iroc since they are both 4th gen rears I will just swap the whole rears. where can I calculate what gears I need?
Basic parts
Twin t3/4 turbos new
S-10 headers flipped
Big FMIC (jims coolers)
HKS bov
Tial 38 wastegates
3" down pipes
4" single exhaust with dynomax straight muffler, very quit
stock 350L98 with a stealth ram intake stock TB
72# inj.
FAST WB ecu
Big fuel sytem etc etc etc
T56 tranny
10 bolt 3:73

a 383 with two PT52 turbos lurking on the horizon

 

I can't believe how strikingly similar our cars are. My twin turbo IROC does the same thing. I have 3.70 gears in a BW 7.75" rear, and I keep it in fourth gear and traps at 112-113 at around 6k (thats what my tach shows anyway). I was running BFG drag radials though. My car actually picked up trap speed when I shifted into 5th, but ET was slower.

 

Yeagh they are very much alike. When i shift in to 5th it just kills the aceleration I actualy lose 5mph and 4 tenths!! I'am running a T56 out of a 95TA what tranny do you have? Is your engine stock? Its nice to finaly see a bunch of us camaro guys going with turbos.

I drove the car to the track 1 hour each way tonight with no problems car is now road worthy

 

What tire size are you running? I have been doing some calculating and need a taller tire my 275-40-17 is 25.7 tall witch puts me at 111mph at 5400rpm, hey that just happens to be what I ran exactly! So if I go with say a 27.9 tall tire it would trap 120mph at 5400rpm it probably won't pull 120 but it might do 115-117 area?

 

I made this gear calculator in excel, If you want I can send it to you.Its easy to use and gives very accurate results.
mhaskell@juno.com

 

I found one at www.f-body.org/gears/ you can select a few different f-body trannies pretty slick

 

The tires I ran were 255/50R16 BFG Drag radials. I measures about 24.75", which gives me approx 5700RPM in 4th at 113mph. I know my tach hit very close to 6000, maybe I stayed in it just a little past the marker, or my tach may be in error. Either way that is way too fast for the stock long block and my stock TPI intake- it is just simply out of the power band. The trans I ran with was an older t56 (I guess it is not a tremec as it was built by borg warner in those earlier years- I think the new t56s are built by tremec though). I am in the process of installing a Tremec TKO 5 speed right now.

 

i like your setup, but looks like you have a lot of tuning to do, i would imagine that those t3/t4's would be able to push your car a lot faster than 13's, i understand your boost is low and all, but i think if you do some tuning you could get it to run a lot faster on that same 8 lbs, also i noticed you said a 383 with twin pt52 was in the future, have you read up on monty's car? 427 sbc, with twin pt52's, and he made 1200 HP if i remember corectly.. he had ALL the go fast goodies, but still, just know what your getting into with the twin pt52's, the rest of the drivetrain can be very expensive

 

Cool! Nice to get to the track and start the tuning. The best I got my old setup (L98, stock heads/cam, DFI, Super Ram, 52mm tb, To4e twin turbos, 2.75" downpipes) was a 12.7@114 with 7 psi. It seems all the L98 headed cars run pretty similar.

Andris

 

I have taken a long look at Montys setup very nice top notch work. I have been balancing a buisness and a hobby so I buy some qaulity parts slowly untill I'am finished, so I do understand what this will end up costing me but man it will be worth it in the end. My biggest problem is the gearing its out of power "flatline" at 5400 in 4th gear and I bet I'am at least a football field away from the traps. Like I said if I shift into 5th it goes 106 if I leave it in 4th and wind it out to 6100 it goes 111mph. So I ordered some 275-60-15 DRs that will give me the gearing I need and will be a nice improvement in the ET department.