brick1234

Biggest question turbo manual 400 rear 3.36 gears Max mph per gear say 6500rpm
1st
2nd
3rd

Haven't done much to the ls 73 since that day besides get rid of 18s for 15s and add glass t tops. I got a pair of 4.11 which are still sitting in shed still. Been going to track last few weeks been trying to adjust carb with vacuum gauge and looks to be going ok. On street tires 295 50 15 couldn't hook every other run was sideways with a best 60ft of 1.96 1/8 mile 8.0 at 91mph. Now today with 3 yr old nitro 275 60 15 ran 6 of 10 runs with 1.75 to 1.8 60ft at 87 to 88.01 with best of 7.78. The biggest problem I'm having is i believe I'm shifting too early going into 3rd in 8th. 2 runs tried to shift at 6500 in first and smoked tires with 22lbs of air. I'm more worried about breaking something if I go down farther in pressure.

derekderek

Don't worry. You will...

gkull

You need to get to look at an online calculator for mph, tire diameter, and rear end ratio

you should not have ever been in 3rd gear in an 1/8th mile drag if you have any rpm type motor with 3.36

gkull

I used a 4.11 rear end for many years of nhra bracket racing all 1/4 mile but from time to time I entered the 1/8th for local events

I was never a street tire or drag radial person. I always thought that it was worth investing in a decaded set of rear tires and wheels and changed them at the track

some ideas for your efforts

http://www.race-track.com/news.asp?TOPIC_ID=532

ajrothm

I shift to 3rd RIGHT AT the 1/8th marker, usually around 101-102 mph with 3.36s and 27” tires. T400 and a tight 10” converter.

If you are shifting to 3rd at 88 mph, you either have way more gear the 3.36s OR you are blowing through the converter.

gkull

Ajrothm, Don't you use drag radials? What pressure gives you the best contact patch and 60 foot times?

ajrothm

Yes, I use a MT Street radial, 255/60/15. They are 27"s. I run at 17 psi warm. Best 60' is 1.51... usually averages .52-.53s.

ajrothm

Going back and watching an old vid, it seems I shift to 3rd a little before the 1/8 actually...


Here is another one, you can see the 1/8 cone sitting on the ground outside of the wall....I clearly shift to 3rd a good bit before that cone:

Amelio

Just to give you some additonal info I run a 4.11 gear with 28" Hoosier Dr's but I am running a 4 speed muncie. I run through the 1/8 in 3rd at 102mph

I have a Turbo 400 and 375 I am thinking of tossing in the car later this year to see what it will do.

brick1234

Appreciate the feedback I will try to hold it in second and see what happens. When you say blowing through converter is that when rpm doesn't drop or want to go? When I go in third it takes a minute to speed up? I definitely have 3.36 did the rpm mph online and is right on it

bjankuski

What rpm do you shift at? With 3.36 gears and 88 mph assuming 2nd gear and 10% convertor slip you would cross the stripe at 5800 rpm.

bence13_33

brick1234
I know this probably doesn't help you much because I run a 4 speed. But I was turning 118mph down the 1/4mile with 215/70/15s and didn't have near the traction problems you are talking about. I for the life of me can't remember my 1/8 times. My 60' times were around 1.9 or so. When I switched to Mickey Thompson ET Streets way later I used to run like 15lbs and I would air up the front tires to like 80lbs (less rolling resistance).

When I would launch I used to tach it up to around 3500RPM or so and slip the clutch pretty hard coming out of the hole as I would roll into the throttle at the same time. The 60' times obviously weren't blistering but it accomplished the goal of traction fairly well.

BKbroiler

Just to throw a few more (slower) numbers into the mix. I have a TH350 in my car, with 3.73 rear and 275/60/15 drag radials. My 2nd to 3rd shift is well before the 1/8 mile mark, at about 5,600 rpms. See slip below, right lane.

brick1234

Im shifting into 3rd about 5500 I believe sometime less seems to not want pull after that . 1st gear is my worst if I try to get on it and shift at 6500 I loose traction Everytime and I don't want to go under 20lb psi in tires and end up breaking, this boosted rx7 is my crypto nite I'm really dead set of beating him. 2 other runs with him were my worst times 2.3 and 2.9 60ft and that's pulling 1st to 6500

brick1234

BKbroiler

You're having traction problems with drag radials on your car? Your 1/8 mile mph is about the same as mine. Since we're both driving C3s, we must be making about the same power. I have NO traction problems. I have a 3,000 stall converter, I hold the tach at 1,200 rpms while I'm staged and floor the gas pedal at the last yellow - which you should be doing too, btw. My car leaves with zero wheelspin and my best 60 ft is 1.69. Maybe your tires are older than you think.

brick1234

Been busy with work, I think I solved a few issues

1. Last time After a few runs the car would start to act up, wanting to stall/die. Thought I figured out carb for most part, friend suggested it could be something electrical/ignition as well. So what you know one spark plug wire was burnt most the way through figures.

2. Checked the plugs besides the one with burnt wire was very dark (replaced all). Going from internet how spark plugs should look when lean or rich, it looks like more towards rich condition but not as dark as the one. Replaced all wires as well and seems to drive a lot better and idle way better.

3. The 275 60 nitros are about 3yrs old with a descent amount of driving on them and now the 30 plus passes at the strip last 4 weeks.

just got tires today amongst everything else this morning. Decided to go with a fresh brand new pair of 275 50 15 nittos drags over the 60s on my spare Convo pro rims. If I got everything right now I believe it should due much better with the shorter tires since I'm under geared for my cam anyways. On the 295 hanook had the best mph but they are on my other car and didn't put them back on after 1st week trying with 275 60s. If I get a chance to go this week hopefully that solved some of the issues I was having.

ajrothm

Yeah the shorter stickier tires should help you for sure. You could potentially run some 11.90s in good air if you can hook and go a 1.6x 60'. Pretty solid numbers.

For the 1/8, I figure you'll go some 7.60s now if you can get some decent air. Play with shift points, try to shift the 1-2 much earlier.... The T400 doesn't like real high rpms in 1st gear....(drum speed). Usually shift the 1-2 about 200-300 rpms earlier then the 2-3. You just need to experiment and see what your engine likes.

You better hurry before the good air is gone for the season.

The Money Pit

These videos remind me of pulling out onto the beltway at rush hour. Nice solid launch that gets the job done with out all the show. 10 seconds is moving...........

brick1234

Went last night constantly got low 1.7s 60 foot with best 7.69@88.60 all other runs were 7.70 to 7.78@ 87.67 to 88.30mph. Only got ten runs and best time was when I changed the timing (3 runs) two of the runs were my worst. One with best 60foot 1.64 but shifted to 3rd instead of second 8.2 @84 and 8.3 . I tried to power brake but didn't help leaves better from idle and still while waiting on line is stalling sometimes. my friend will be tunning the carb for me this weekend if he's free, he's going to take a look at it and see if I need to change the jets or not. I was actually happy with the night though I lost 3 races 2 which were to track cars and we're my best runs. Only Street car I lost to was a challenger 392 had a 1.62 60ft 7.35 @94.48 but beat a stock one that ran 8.09 @ 88.90 later that night. C5, 5th gen Camaro, ls1 Camaro, then all charger and challengers
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