Yellow Bullet Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
2,836 Posts
Discussion Starter #1
Anyone here have experience running a car making decent power with a small converter on a chassis dyno? I am looking at switching fuels in my Hot Street car so we can run an NMCA west race and dont have time to dyno the motor. I might be able to find time to het a chassis dyno but have no experience with them and am a bit leary. FWIW the engine made 1314hp on the dyno and the car has a 7" converter. Not looking at tearing my junk up and am curious on eother experieces with anything like this. OR am I going to be better off at the track trying to adapt. To ad to it the air at that race will be much better than what we see here in Vegas.
 

·
Registered
Joined
·
20,824 Posts
I have not got that kind of power, but it can be set up for how much it holds back and for how long we use a 950 HP 8" converter with one no troubles. you can run it up in high then mat it and coast down, its about like making a pass from what I have seen. Just tune to move the mark and dont compair it to your engine dyno sheet.
 

·
Registered
Joined
·
786 Posts
Try to have the tune as close as possible before you go they can put a he'll of a load on the drive train.
 

·
Registered
Joined
·
2,836 Posts
Discussion Starter #4
So from what I am hearing we are likely just as well off to make the changes to the car and head to the track. I have 02's on the car. We just get a limited number of shots at the track and was trying to decide if this was a viable option or not.

I have heard horror stories from chassis dunos with dedicated drag cars with small converters and really dont want to tear anything up. We are good to go, or at least close with our current set up but were thinking of trying the 10.5NA stuff with the NMCA which requires a different fuel that we built this thing for. Just searching options.

I am leaving tomorrow and racing the next two weeks with my other car so just no time to pull the motor and find a dyno. Was looking for a way to maybe get close a little quicker. Not sure this is a good option or not.
 

·
Registered
Joined
·
1,474 Posts
Prob only issues I've seen or heard of is slicks can be eaten up on rollers and dont be discourages with numbers.out of the cars I've dynoed I've seen a few that made low hp but went fast.so if it only makes 800 rwhp don't be pissed.usally depending on converter air pressure and rear.look for a 20-25% loss.mostly use it as a tool for changes.goodluck
 

·
Registered
Joined
·
786 Posts
The six pulls I made didn't hurt the slicks. We ran 20psi in them to get them off the sidewall. Keep in mind the rollers look like diamond plate. They had me run it through all the gears shifting at 3500. The wot was done in high and started the test from 4500 to 8000.
 

·
pig hunter
Joined
·
9,424 Posts
good tool as a tuning aid doing a-b-a testing but don't take the hp number to hart. just pulled a 1200hp+bbc off the engine dyno a few months ago and ran it on the chassis dyno a few weeks back and it only shows 779 to the wheels lol.. the car has already ran 161mph @ 3340# so you can see the huge differance there..
 

·
Registered
Joined
·
786 Posts
I had the same experience numbers were low. That wasn't the only one I had and with my earlier post you can probably figure out what happened.
 

·
Registered
Joined
·
2,836 Posts
Discussion Starter #10
I am not worried abotu the power numbers at all...Just looking to get carbs close. My converter stalls at 8200 so not sure how much of this kind of stuff is an issue. Starting a pull at 4500 woudl ikely kill the poor thing. I make peak HP at almost twice that rpm. Peak TQ was at 7500...Once again not sure this is the best way to go. FWIW and those who dont know it is a Pro Stock piece, so makes power upstairs.
 

·
Registered
Joined
·
786 Posts
The car had a sbc 18 degree with a f2 on it. You might want to consider maybe a track rental were you will be racing at.
 

·
Registered
Joined
·
2,836 Posts
Discussion Starter #12
Well after some phone time today I think we are just gonna give it a shot. I think we have a handle on a decent baseline for the carbs. Just not sure about the chassis dyno deal. I appreciate the info. Oh yeah it seems obviouos typing from a smart phone is not a good idea for me either :)
 

·
Registered
Joined
·
418 Posts
I own and operate a dynojet chassis dyno........dont listen to the horror stories...
I tuned my ride on the dyno and raced nearly 5 years on that tune with NO changes..thats reliable..

Last month we tuned a 2460 lb nova with a n/a 585bbc....baseline was 705 rwhp...nine pulls later we got 774 !!!
his et went front 5.34 down to 5.07(in warmer weather to boot)...
 

·
Registered
Joined
·
2,836 Posts
Discussion Starter #14
How much RPM can say your dynojet tolerate. My drivesahft RPM in high gear is right at 9200.
 

·
Registered
Joined
·
3,173 Posts
How much RPM can say your dynojet tolerate. My drivesahft RPM in high gear is right at 9200.
The dyno doesnt know rpm it only knows wheelspeed. The problem you are going to have is your converter. Once you hit it in high gear the motor is instantly gonna go to 8000 and then ride the converter until it starts to lock up which will be fine, but you will only get numbers to tune off of from wherever the converter starts to stall and your max rpm.
 

·
Registered
Joined
·
34 Posts
I know this is an old post but that is exactly what i had happen at dyno. My stall is 5500 and i had limiter set to 6000. I should have increased the rpms prior to full throttle. I hit it at 2000 rpm and went right to limiter
 
1 - 16 of 16 Posts
Top