quote:

Originally posted by Mike Rietow:
Greg Kell*y is thinking of tune in terms of boost I'm guessing, only because converter stall is relative to boost the same as converter stall is relative to nitrous percentage (power) using a progressor.

We have a difference of 600-700 rpm of observed stall from the flash stall leave to the drop back at shift.

Did you turn 150 hp nitrous on down track before the shift? If not, I'd have the converter looked at if it were mine. I could see a difference of 200rpm of observed stall but not 700 rpm.

Looking at the graph, it's 6000 stall at the leave and 6600-6700 drop back observed stall at the shift. I can't think of anything in an N/A tune that could account for a difference of 700 rpms of observed stall. But I'm all ears.

not sure if all that was in response to the log I posted. But no that is not a boosted car. It does have nitrous and it was activated 4.0 seconds into the run. However I'm trying to point out to Colorado that the first 2 seconds of his run should have a RPM profile like this. And explains my thinking that he has a tune-up issue. RPM should jump almost straight up to stall, then level out for a second then climb to shift, drop back to stall (within 100) then slowly accelerate to the trap RPM.

Here's an example of a wicked fast 7.40 dragster of TOP38 from like 2005 (probably the smartest guy on this board (used to be 2nd smartest)). Note his engine RPM actually goes down maybe 50 rpm 1.5 secs into the run - common occurrence. Al probably had one of those magic B&M 608 converters in it

The one thing on that graph Greg is that was the second hit when the car spun. The vid is from the first run but didn't get a run graph from that. It pretty much spun at the hit.

Coloradoracer

I went through this tread quickly so I got the basic gist. My 2 cents..

your 4.10 gear with those tires is fine, and honestly a 4.30 would likely be better. Rear gear and tire should be matched to give you the trap rpm the motor was built for!

Your car is long for your ET & speed

Why are you leaving so high? 5400 is insane.

If your converter was built to work with 300 HP of NOS then it's way too tight without the NOS. Pick your poison! At that level of NOS I can't see using an NOS converter for your combo unless your going to use it all the time, otherwise set it up for NA! & spray it when you want to go faster. Ya you will give up some ET but you will be able to race the car!

The one rpm graph you posted is a mess, first gear shows a converter way to tight or motor issues (or both) and once it shifts it breaks the tires loose so the track is junk to boot.

The one picture I saw at the hit shows your killing the tires, tire pressure changes from 5 or 5.5 pounds isn't gonna fix that. It also looks to me that the motor is pointing up relative to the chassis and its also mounted high in the car. From what I can see your killing the tires at the hit from all directions: too tight converter, too much leave rpm and the chassis/engine setup. But you don't have anywhere near the power needed to develop any wheel speed! Never gonna work! With this combo the only way to get any kind of consistency would be to limp it off the line.

Using the NOS very early in the run may get this combo to work....

This is a case where a data logger would be worth it's weight in gold! You would easily pay for one from the benefits it will provide by allowing you to fix the car in a fraction of the time without one!

Good luck.

Top38, I'll pm you later with more info. At work right now. Thanks!

quote:

Originally posted by Greg Kelley:

quote:

Originally posted by Mike Rietow:
Greg Kell*y is thinking of tune in terms of boost I'm guessing, only because converter stall is relative to boost the same as converter stall is relative to nitrous percentage (power) using a progressor.

We have a difference of 600-700 rpm of observed stall from the flash stall leave to the drop back at shift.

Did you turn 150 hp nitrous on down track before the shift? If not, I'd have the converter looked at if it were mine. I could see a difference of 200rpm of observed stall but not 700 rpm.

Looking at the graph, it's 6000 stall at the leave and 6600-6700 drop back observed stall at the shift. I can't think of anything in an N/A tune that could account for a difference of 700 rpms of observed stall. But I'm all ears.

not sure if all that was in response to the log I posted. my thinking that he has a tune-up issue.

No sir, I never looked at your log. The two arrows tell all about power. I was agreeing with your tune-up thinking being the problem analysis, with the assumption you understood the two arrows represent power at each point in the run. As far as Colorado's car going straight to stall, it did go straight to stall at T- brake release, 6,000 rpm.

I couldn't think of anything in an N/A tuneup that would result this much of a disparity in power, so I mentioned a boosted application.

No sir, I never looked at your log. The two arrows tell all about power. I was agreeing with your tune-up thinking being the problem analysis, with the assumption you understood the two arrows represent power at each point in the run. As far as Colorado's car going straight to stall, it did go straight to stall at T- brake release, 6,000 rpm.

I couldn't think of anything in an N/A tuneup that would result this much of a disparity in power, so I mentioned a boosted application.

[/QUOTE]

No it did NOT go straight up from T brake release to stall based on Greg's post. From T Brake release the rpm graph slopes up to stall which BTW isn't clear at all as to where that really is based on this one graph. Now whether it slopes up due to lack of power or the converter being too tight is another question and based on the info given the converter is certainly too tight without the 300 shot!

What Greg was trying to point out was that a properly fitted converter will basically allow the rpm to go straight up at TB release until it get close to stall when it starts to curve over towards a relatively straight line. How it does this and how long it stays flat is a direct function of the converter design! And just because the rpm lays flat for a given duration does not mean the car is not accelerating down track.

So until he gets the tune up right on the motor and gets to run on a good track, what is seen on the posted rpm graph is GIGO! That's garbage in = garbage out...…….

The two arrows are pointed at the two areas observed stall is indicated on the graph. The observed stall tells you everything about power at the two spots on the track. Nothing else in the graph meaning slopes drop flat using your words, has anything to do with observed stall which is also observed power or tuneup which is what we're talking about. It goes straight to stall, 6000 rpm. If you wanna say it doesn't go straight to stall after T-brake release, that's cool but it's an observable fact it does go straight 6000 rpm stall after T-brake release, the same as the graph also shows a drop back stall after the shift of 6600-6700 the arrow on the right.

None of this is subjective (opinion) it's observable fact and also based on the fundamentals of automotive hi performance.

I fixed it for you!

The two arrows are pointed at the two areas observed stall is indicated on the graph in my opinion. The observed stall tells you everything about power at the two spots on the track based on the current tune up of the motor and track conditions. If you wanna say it doesn't go straight to stall after T-brake release, that's cool but it's an observable fact it does go straight 6000 rpm stall after T-brake release, the same as the graph also shows a drop back stall after the shift of 6600-6700 the arrow on the right which again is a function of the motor tune up and possibly the loose track conditions.

Now let me make one more point clear to you,,, by straight up from T Brake release both Greg and myself mean basically a straight line vertically up, not leaning over or as I called sloped as this graph does. SO by our definition it is not straight up! which indicates a tight converter for his combo and state of tune and which makes perfect sense since he stated the converter was setup for a 300 HP shot of NOS which he was not using.

You may now carry on.

If you're talking tune or in other words power, the arrows are pointed at the only two areas on the graph power or tune apply's, or can be interpreted, observed stall.

If you wanna talk how the graph looks slopes dips flat your words, then you're talking subjectively (opinion).

To tell me one more thing you'll have to tell me the first thing. Now do you wanna talk power or in other words tune > observed stall.

Or how the graph should look? If you wanna talk how the graph should look, I'll get out of your way. Opinions IMO are boring.

Just a note on the converter. It was configured for a 300 shot of nitrous, on gas, in DENVER CO.....not for alky or here. I know it's not right, but I'm not gonna drop coin until I know what to get.

Top38, I'll see s you a pm in a bit. Just got home

quote:

Originally posted by Coloradoracer:
Just a note on the converter. It was configured for a 300 shot of nitrous, on gas, in DENVER CO.....not for alky or here. I know it's not right, but I'm not gonna drop coin until I know what to get.

Top38, I'll see s you a pm in a bit. Just got home

So in Denver that was a 5600 - 5700 converter and with the 300 hp 6600 - 6700.

So you need to loosen it 600 - 700 rpm for Florida N/A.

That sounds par for the course dragster in the 4.40's, 6700 stall, easier on the tire.

That's the good thing about having the observed stall on this graph, the converter company's can look at that and know exactly what you need based on their large database of cars with their converters, and comparable power.

It did flash to about 5800ish in denver on motor alone. Life got in the way before I could spray it....

When I unload the car Friday I'm going to stall it on the brake and see what it does. I think that number would be helpful

quote:

Originally posted by Coloradoracer:
It did flash to about 5800ish in denver on motor alone. Life got in the way before I could spray it....

When I unload the car Friday I'm going to stall it on the brake and see what it does. I think that number would be helpful

Make it good, you only wanna do it once with a sprag converter. I have a PTC sprag converter a friend had in his attic 10 years I bought after trying it. Cool little 8" I decked on the converter once. I wouldn't do it again to it, I like it too much. Plus I know what it is now. Ya really don't wanna do that with a sprag converter. It'll be 6000 but I'd probably double check verify that myself if it were mine, especially if it's getting re-worked anyway.

What the hell, I'll throw in my two cents and I'm not near as smart as most of these guys but 1800 bucks or so from Greg will probably get you a logger that like Top38 previously mentioned will tell you a bunch of what you need to know. Looks to me like it would be money well spent. I know it's some of the best money I ever spent on the mine. Good luck Mark, hope you get it figured out.

quote:

Originally posted by Mike Rietow:
If you're talking tune or in other words power, the arrows are pointed at the only two areas on the graph power or tune apply's, or can be interpreted, observed stall.

If you wanna talk how the graph looks slopes dips flat your words, then you're talking subjectively (opinion).

To tell me one more thing you'll have to tell me the first thing. Now do you wanna talk power or in other words tune > observed stall.

Or how the graph should look? If you wanna talk how the graph should look, I'll get out of your way. Opinions IMO are boring.

OK I give you a lesson for free, but last time.....

You are obsessed with your red arrows, stall rpm's, changing trans first gear ratios ,,bla bla, bla!

But you have totally missed one of the most important tuning aids for faster hardtail dragsters! Which BTW is MIA on Mark's car.

It's called a wheelie bar! and the faster the combo is, the MORE your need one!!!!!! And it ain't there to prevent big wheelies either if you have a clue!

So your so smart, you tell us all what's next!

quote:

It's called a wheelie bar! and the faster the combo is, the MORE your need one!!!!!! And it ain't there to prevent big wheelies either if you have a clue!

that would fix what see the chassis also

quote:

Originally posted by rusty:

quote:

It's called a wheelie bar! and the faster the combo is, the MORE your need one!!!!!! And it ain't there to prevent big wheelies either if you have a clue!

that would fix what see the chassis also

Only thing is, I don't think it will adjust that low, and I'm not picking the front end up enough to hit it yet......guess I need to fix that!!!!

this is a place i would drill holes lol

Colorado, It needs a 6700 spragless that flash stalls 6850, it'll fix your wheel speed issues. The car will be consistently easier on the tire and keep the car stretched out early in the run.

The indicator (trend) to take into account is the 5800 converter in Denver which stalls 6600 6700 with the additional 300hp nitrous.

The blue arrow on the left is the flash stall rpm, the blue arrow on the right is the stall rpm, with this also being the observed stall rpm if you decked it on the T - brake, no high side chip. The yellow arrow at the end of the run is another telltale sign of a spragless torque converter in play, dip in rpm spiking up slightly when you step off.





Top 38, Factual only concerns itself with what is the case rather than interpretations or reactions to it.

This message has been edited. Last edited by: Mike Rietow,

Well, I know the converter isn't right, but after today I'll know what it currently does behind my stuff. It may change a bit as my tune gets better but at least I'll have an idea of where it's at. I also know my tune isn't right yet, but it's getting there. Just need to keep chipping away at it.