Hi people, My car has 455hp at the engine, auto with 2800 converter, 3.45 diff gears, M/T ET street tyres (28/10.5/16). I seem to be stuck at 12.2, I can only leave with 1-2 psi boost without wheelspin. I realize the diff gears should be 3.89 or 4.11(I will change them next time out). where can I pick up the time??

What boost were you running to achieve that time and what mph did you get, Possible the 3.9 gears might get a little more out of it but then again I have seen a few cars break into low 11's using the standard 3.45 ratio gears, my VL ran a high 12 at 107 mph on 13psi with a very standard set up and I run the 3.89 rear gears and I feel maybe if I used 3.45's my mph might improve as I can't really go any faster than 107 mph with my current set up.

Red RB30 Jet: Ur exactly right on your gears theory, ur miles will lift with the standard gears dude. HSVSUX: Dude your car is making 455rwhp and thats good power, so id suggest dont look at your times as an engine-power problem. I've seen cars with less grab a high ten, that power's good for a low 11, even high 10 man. If anything look at the way in which your trying to get your power to the ground. The slicks sound right, however a 2800 converter may not be big enough. The fact that your not getting any boost off the line could be a problem, something in the 3k mark for the converter (i wouldnt know exactly) may help u get atleast 10 psi off the line, I suggest u leave the gears for now, and get some info on what size converter should be suiting your power.

455HP is the engine HP and the M/T tyres are the ET streets I think the turbo is a bit tired, the car does not start to move out until about 80-100 feet. The Boost was set to 18.5lbs and the MPH 117. I have run the car before with 16lbs, 4.11 gears and worse tyres and did a 12.3. I dont care if the MPH is down a bit. Also I can get more Boost off the line but it takes about 10 seconds to load up and will just start turning the tyres if over 3-5lbs.

Do you do a big burnout before you run? are your slicks old or hard? something is not right if you are turning the tyres that easily. I agree that a bigger converter is needed too.

ok well i have roughly about the same power as you but only difference is mine is a 5spd manual. i run full Mickey Thompson ET's on the rear and they get traction very well. If u can get a new convertor and get more boost on board b4 launching then u will get a 11 easy. I run anti lag so I can get about 14psi up for a launch. I still run a t3 though and the manual slows it down heaps up the top so i have only run a 12.08 so far but if u can get the boost up for a nice launch and some full slicks under the rear then u should get a 11 easy. What tire pressure do you run in your rear tyres and what 60fts are you doing? Ive still got the stock diff and tranny in mine as well. i think if you sort out your launch then the gears will be ok

TYRE PRESSURE WAS AT 13-14PSI COLD. 60 FT TIME WAS 2.05 - 2.1 WOULD A 3500 HI-STALL BE TO HIGH?

im not a auto expert but it depends on how much u drive the car on the street. 3500 would be pretty good mix if use car as a street/race car. that tyre pressure is ok. i run 21psi in my ETS. Just need to get that bosot of the line i do a 1.6 60ft so if u can do that as well then taht is almost half a sec off your time and into the 11's

I agree, generally cars that run 11's have 3000rpm or bigger stalls and also have 3.7 - 4.5 diff gears The main point being as long as you can break traction in the dry with minimum effort, all is good Some original photos have not been recovered yet.

I persume your running at least 1 x tranny cooler at the moment with your current stall? when you go 3000rpm and above stall you need 2 x tranny coolers to keep that box from melting. Just piggy back them side by side or one in front of the other she'll be cookies then! Some original photos have not been recovered yet.

I run 2 trans coolers, my tyres were new (freshly imported). I might get a 3500 converter and run it just at the strip. Some original photos have not been recovered yet.

HSVSUX Not sure what your problem could be. Perhaps check that your auto is still healthy (bands are ok etc) and that your tyres are of good quality and aren't too over-inflated for slicks. I say this b/c my bro had the same converter as you 2800rpm, slicks and 3.45 diff gears with less power and still managed a 12.07@111mph. His 60ft time was 1.70 and this is where he made up good time hence why I say something is not right for you when your getting 'off the line'. So your stall speed is not your limiting factor. Don't forget even with a 2800 stall you can still leave the line around 3000rpm if you hold the brake pedal down hard enough I did a similar 60ft time to you in my old VLt running on 225 street tyres and it was a manual so that says something. I hope I have helped. Some original photos have not been recovered yet.

A transbrake equipped auto is the best for big launches. Of course that means u'll be up for something like a trimatic or c4 (assuming u want to keep 3 gears). i believe a dood in SA has made a 4sp jatco transbrake eqipped autobox which was being tested in JETVL(SA) but I haven't heard anything about that in a while.... of course going to a race prepped trimatic with transbrake is very pricey, and it wont help you out when u hit the circuit next.

HSV SUX - You run a auto built by Yarra Valley right, the convertor Tony Spooner always recommends and supply's is a TCI 2,800rpm. Which is ok for general street work but if you are serious you will have to run a bigger convertor, A mate of mine also has a Yarra Valley built auto and we just recently pulled the 2,800rpm convertor out and replaced it with a TCE 3,200rpm stall convertor and I can tell you it made a huge differance to my mates car it does'nt feel so laggey, we are just going to see how long a Yarra Valley jatco will hold together his car is built to run decent times and has not been on the track as yet. :P

A transbrake Jatco 4 speed I don't think it would last to long, I believe Raceglide's already tried it and it failed, but then again some one else out there may make it a reality. Some original photos have not been recovered yet.

Your 60ft time is a little high... If you go for the 4.11's, you'll get a much better launch..much less likely to get tyre slip/spin. Don't worry about top end too much, concentrate on getting the launch right first. I have seen people go down a rim diameter or two for their slicks, it's a cheap way of geting a better ratio on the rearend while still having good street gears. Perhaps get some 14" steelies widened for the drags perhaps, just make sure yout tyre diameter is redused as well....and throw your other wheels in the boot as ballast. How hard is your rear suspension? Regards, Andrew.

Bro the best bet becuase your 60ft is 2.05 thats your problem why you cant crack the 11s, it would have to be about a 1.6 to a 1.8 for you to run 11s, because your mph shows a 11 second pass, so your best bet would keep the 3.45 gears for now, do the auto, go a bigger stall, like a 3500 or 3800rpm with a good shift kit, then dyno it and take it to the track see what you get, then throw a set of 3.9 gears in it, but like most 10 11sec cars these days, most dont run on the street and some do but they never drive them on the highway.

HSVSUX I was making the assumption in my post that you still want the car to be a good daily street driver and be able to run decent times on the strip. This is b/c you still have the jatco 4sp and so I assume you enjoy the overdrive gear for those longs drives and haven't lowered your diff gears any more than standard. If that's not the case, then sure go bigger stally but see if you score a ride with someone who already has that size stally on their VLt before making your decision. A friend of mine regretted going to a 3200 stall (from standard) since 99% of his driving was on the street, especially with the increase fuel consumption too. Having said this however it's all in the setup of turbo sizing to stall speed, among other things. How else could Bleuy1 (now retired white VLt) of run 10.9 with only a 3000rpm stall......... Note I have met and spoken with the owner (well he is holding it for the time being) and driver of bluey1 on many occasions and this was in fact the stall speed on the car.....and no it didn't run nos or extra injectors or more than 22psi boost either...

While my motor is out of commission I getting the gearbox repaired too (bit of an oil leak). Bearing in mind its an atmo auto Jatco, I am looking at an 2500 stall converter. do I need to run a trans cooler with this setup? what else should I look for when doing this gearbox up?

yeh man for sure ... at least one trannie cooler if not 2. yarra valley autos run 2 transcoolers with their beefed up jatcos with 2800 stallies...