Going to smaller carb in the slick?

[powerslide]

Anyone put a smaller carb on when the tracks go slick? If you had 700hp for qualifying and heats and have a driver who doesnt understand the track will only hold 550 come feature time. Going from like a 830 to a 650 would that make any difference or am i just going to melt a motor down trying this?

[hpontap]

No way I would run a smaller carb than what the engine needs. There are a couple of things you could do. Take a little timing out of it, limit the throttle travel or try a slick track carb turned all the way down. But the driver is the biggest/easiest/cheapest adjustment you could make. Good luck.

[powerslide]

No way I would run a smaller carb than what the engine needs.

need the why so i can make a decision for myself. I like to be informed in my decisions thanks

[giffordracing]

We had a 750cfm built for a SB-2 this year to calm it down fro 800+ for the slick seemed to work good for us

[charcoal01]

been told that disconnecting the secondary's will work. supposedly cuts power by about 30%. never tried it so i can't say for sure.

[hogracer3d]

Contrary to popular belief, it works just fine.
We took the VDL 850 off of our 700hp 406 on the dyno, and installed a gauge legal 4412 VDL 2-bbl, and it made 536hp and no ill effects.

Common belief is that the small carb goes lean up top, not true, they go a little rich, and therefore are perfectly ok.

We actually did it once on a two day show, 1st day heavy/tacky = 4-bbl, 2nd day dust bowl dry= 2-bbl

you'll be fine..........

[powerslide]

Now on to the next question.
How much power would you kill on a 625-650hp motor with a 650 vs a 750. I Exaggerated in my original post we dont have that much power but driver just doesnt understand the concept of throttle control he won more races with a 355 vortec motor than he has since he got a "good" motor. Anywho done rambling just curious if anyone knows a percentage it might kill on that type of motor.

To the guy with the secondary comment. Does it really kill that little? i figured it would be close to 50% with the barrels all being the same size...

[turner]

On a 3800 lb drag car, we ran 11.30 at 117 with a 850 double pumper, and by unhooking the secondaries. it runs 12.00 at 112.Thats about 75 hp on a 500 hp engine in our expeirence.

[powerslide]

On a 3800 lb drag car, we ran 11.30 at 117 with a 850 double pumper, and by unhooking the secondaries. it runs 12.00 at 112.Thats about 75 hp on a 500 hp engine in our expeirence.

is that 500 before unhooking the secondaries? thanks for the help

[turner]

Yes.That was around 500 hp before unhooking the secondaries.Didnt touch jets or anything when we unhooked them and we have done it for years.Good luck.

[RCJ]

It's a gamble on what it will do.If your 830 has jets and bleeds that are tuned to your motor and you throw a 650 that is not steup that good it could be a big change.Or if your 830 is not that good and you get lucky and the 650 has a good fuel curve for your motor might not be much change.We backed 8 degrees of timing out of a L/M motor on the dyno and it killed 50 lbs of torque on the bottom but only 15 hp at peak.

[hpontap]

Originally Posted by hpontap
No way I would run a smaller carb than what the engine needs.
need the why so i can make a decision for myself. I like to be informed in my decisions thanks

My reasons are: I've backed my engine down before only to have the track rubber up and then didnt have enough ( that pisses you off )
Everytime you change carbs especially at the track, you stand the chance of dropping something down the intake.
Had one of my carbs dropped when the guy was taking it back to the trailer and cost me another baseplate and time to get it right again.
And if the driver is not understanding the car is not hooked, then he is burning up tires and turning the engine higher than need be also.
I spend a lot of time getting the carb/engine right and if the driver cant use his right foot like he should, all of that hard work and time are for nothing.
Is it possible that engine engine has a really sharp torque curve? Possible cam change might be in order.

[RCJ]

You might try a vaccum or Willy's slick track carb.I 've tested back to back with the willy's and a mechanical.On the fastest setting the willy's was softer at the first hit of the throttle but ran down the straightaway good.Never tried the slowers settings on the willys.I keep the car so tight that we need the low end power to turn it if I get it to tight.

[soonersublime]

I would go w/ the willy's slick track carb if it were my driver. Would be easier to adjust instead of changing it out. This is exactly what that carb is made for.

[parrot69777]

Just my opinion....but drivers who have to back something down on their engine for a slick track...don't have smooth throttle control, can't figure out how to keep their tires hooked up, drive too deep in the corner, missed the setup, or just continually miss their marks. The drivers foot is the best adjustment there is.

HPONTAP has a very good point about the track rubbering up. If your on a big track....most of the time the only part that goes slick is the corners. Still need the big ponies for the straight a ways. Good drivers will almost idle through the corners and then stand on it when they hit the good stuff. Have seen guys gain several car lengths a lap over drivers who can't figure it out.