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Dragster doesn’t run what it should
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DRR Sportsman
posted
Been helping a friend with this issue and we’ve been collectively beating our heads against the wall so I thought I’d reach out for some ideas.

He’s got an Ed Quay 4 link car weighs 1950 race ready with driver. It has a 565 new from Shafiroff last year, Brodix BB3X heads. 4.10 gear, power glide, the usual stuff. Carbureted on gas. It should go 7.70s at over 170 at minimum.

Last year the best he got out of it was a 7.95 in good air, usually it was low 8s. Low 160s for mph. At the beginning of last season it was suggested that he go to larger fuel lines and regulator and he did that. I believe he tried a different carb as well. Verified that it opens to wide open throttle. Towards the end of last season we tried my spare converter that had just been 7.47 in my wife’s car and it ran exactly the same low 8s.

In the off season he had a prominent local builder go through the engine. He found that it was low on compression and didn’t like how the cam was installed. Rebuilt it, 14.5:1 compression, ran it on his dyno and it made 875 HP. So now we know the engine is making power for sure and figured it would run what we thought it should run all the time. He also installed a crank trigger and a brand new MSD 7AL3 box.

Took the car out and goes consistent 8 teens at 163. We tested crank trigger polarity this weekend, when we swapped the wires the timing became erratic(retarded like 20deg) when revving it a little, so we put it back where it was. He’s got the timing at 35. Also tried another 7AL3 and crank trigger pick-up with the same results.

The 60’ times were slow too like 1.16 or 1.17. Everything about the time slip agrees that it’s an 8 second car - low mph, slow 60’, etc. Car sounds good, nice and crisp. No clues that I can find to point us in the direction of the issue. This thing should go 170+ mph and 7.70s in its sleep. Likely more like 60s at 175 if it’s right but we’re not even in that zip code!

Any thoughts on where to look next?
 
Posts: 713 | Location: Upstate NY | Registered: July 02, 2013Reply With QuoteReport This Post
DRR Trophy
Picture of NC3x58
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Lets get down and dirty with motor specs, most people here will ask that and want to know which will help them (not necessarily me) determine where to look. Cam specs in general, intake manifold.. a basic rundown of the engine itself.


Nick Craig

1971 Camaro Split Bumper
376ci LS3
 
Posts: 410 | Location: Ohio | Registered: December 28, 2013Reply With QuoteReport This Post
DRR Pro
Picture of SlyFox
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Rotational drag in the differential and/or transmission?


Mike
 
Posts: 1562 | Location: Marietta, GA | Registered: December 09, 2005Reply With QuoteReport This Post
DRR Sportsman
Picture of Mark Yeager
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Whats the converter stall at?


Mark Yeager
 
Posts: 1380 | Location: Hollister,CA | Registered: April 06, 2004Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
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It was slow before and is still slow after the engine was gone thru....and improved...

875 is pretty weak for a 565 but still should be quicker and faster...

Converter......would really have to be mismatched or hurt
Brake drag......but, My new MW brakes have ZERO drag compared to the Wilwood I took off....and made no difference going down the track from the numbers I see on my tickets...
Rear diff tight......that's a stretch.....

My old 509 went 7.70s at 170+ with an alcohol 1050 carb.
8" converter.....sprag type or spragless…..

Same weight car and similar equipment....

My 565 runs 7.50's and quicker in good air anytime I bracket raced it.....

7.60 or quicker at Numidia in 4000' air...and never slower than 176-177 carb or injection...

No real good ideas....
 
Posts: 2733 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR Sportsman
Picture of TD3550
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Complete long block? What BB3 head? 2.300?. Just by chance, is that a private grind from Comp. Merlin X or an SV Should be a 70 car with ease.
Short on steam ~Yes.
 
Posts: 1409 | Location: Under a Truck | Registered: August 23, 2013Reply With QuoteReport This Post
DRR S/Pro
Picture of Big Steve
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I agree 875hp is pretty weak for a 565 but should run better than that. My 565 at 2000lbs went 7.50s on alky. Car would be a little happier with a 4:30 gear but not 4-5 tenths happier.

That car should 60 in the 1.08 range.

I know you said you swapped converters but that's sure what its pointing too, what's it flashing too and what RPM is it shifting at? any idea what the fall back is?

Stupid question but are you sure it has full throttle? no T stop or SLE that could be causing an issue?
 
Posts: 2420 | Location: Moving back to the door side | Registered: April 30, 2010Reply With QuoteReport This Post



DRR Top Comp
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The converter that "just went 7.47" in your wife's car was too tight for your buddy's dragster. Most likely the same as the converter in your buddy's dragster is. That would make sense right?, both converters ran the same in your buddy's dragster, right?

We need the tire size and rpm at the stripe, to know for sure.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
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Its slow right from the hit with 60's that slow and a good 10 mph at the stripe...

Whats the finish line RPM ?

My car is always around 7300 going 173-174 in S/C mode....a best of 175-176 @ 8.90

A little higher WOT at 177-178+ but I've never seen 7500 on replay tach or Grid....

4.10 gear, 33.5 tires

With Rons injection 60' was 1.07-1.08

A 1050 Carb on gas a little slower maybe 1.10-1.11 at worst...

9" spragless Select.....never saw launch rpm higher than about 6200-6300 bracket racing leaving from 4400-4600

Shift on time or rpm and usually around 7000 or less !

Hard to imagine a 565 being that slow....and not hurt !


Compression test it, leak it.....check the valve
train for any issues...
 
Posts: 2733 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR S/Pro
Picture of Lenny5160
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I almost think the engine itself can be ruled out as a variable. It was slow, rebuilt and dynoed, and still slow.

The only way to know for sure is to put it in a different car or put a different engine in this car.

I agree that the 7.47 car converter would likely be too tight, but I don't know if it would be off enough to turn a 7.60-70 car into a 8.0+ car.

It's just performing like a low-700s hp car all the way down the track. I wish I had a great suggestion but it could be a hundred things.


Tony Leonard
 
Posts: 3153 | Location: Inver Grove Heights, MN | Registered: March 18, 2004Reply With QuoteReport This Post
DRR Sportsman
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To answer some questions, this is the engine he bought. I’m not sure which BB3X head or what cam it has. It acts like it’s down on power but again this was just freshened and dynod at 875. Maybe weak for a 565 but we’re still 10 mph and a half a second off for 875 HP. Like Lenny said I don’t think it’s the engine bc it was slow last year, freshened, dynoed, and still slow.

My converter that “just went 7.47 in my wife’s car” is an 8” sprag and it was loose as a goose in her car, 6800 flash and lots of slip up top so my thought process was it should be pretty close in a car with a little less power. Certainly close enough to rule out his old converter as having a major problem. A couple or few hundred stall rpm isn’t going to slow it up a half second. I’ve run my junk with a flash as tight as 5800 and as loose as 6700 and it runs within a tenth and 1 or 2 mph.

As far as RPMs, he has no data logger. Had the tach in a real bad spot to see with GoPro last year, behind the shifter. Was only able to get stripe rpm not the flash or fallback and as I recall it agreed with the slow mph, 6900-7000 or something in that range. Just tried calling him to confirm but no answer. This year he moved the tach higher on the dash and not sure if he got a good GoPro video of it yet.

Big Steve not a stupid question WOT is one thing I verified this weekend. Last year he had no throttle stop, this year he has a stop but no timers activated. It acts like it’s half throttle!

Like Lenny said it acts like a 700hp car but he has a dyno sheet from a trusted builder whose dyno is conservative if anything that says otherwise. It would have to be some crazy parasitic drag somewhere to slow it up that much so I think that’s a stretch.

Just very bizarre and it feels like something simple is missing but nobody can figure out what it is!
 
Posts: 713 | Location: Upstate NY | Registered: July 02, 2013Reply With QuoteReport This Post
DRR Trophy
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875 on the dyno should go under 7.60 in that car. I would be looking for a problem behind the flexplate. JMO. Please keep us posted!
 
Posts: 39 | Location: so. ca. | Registered: June 28, 2010Reply With QuoteReport This Post
DRR Pro
Picture of rusty
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quote:
We tested crank trigger polarity this weekend, when we swapped the wires the timing became erratic(retarded like 20deg) when revving it a little, so we put it back where it was. He’s got the timing at 35. Also tried another 7AL3 and crank trigger pick-up with the same results.

on analog wires should be swapped to show most retard,then reset timing


honesty is the best policy,insanity is a better deffense
1.036, 6.16@ 224

 
Posts: 1408 | Location: texas | Registered: February 17, 2006Reply With QuoteReport This Post
DRR Trophy
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i would check the intake gasket, i have seen a few cause people headaches! but then again im a ford guy.
 
Posts: 12 | Location: maryland | Registered: August 09, 2009Reply With QuoteReport This Post



DRR Sportsman
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quote:
Originally posted by rusty:
quote:
We tested crank trigger polarity this weekend, when we swapped the wires the timing became erratic(retarded like 20deg) when revving it a little, so we put it back where it was. He’s got the timing at 35. Also tried another 7AL3 and crank trigger pick-up with the same results.

on analog wires should be swapped to show most retard,then reset timing


When the polarity was changed the timing did advance, then it would retard 20 degrees when revving it a little. So it was originaly at the most retarded polarity.
 
Posts: 713 | Location: Upstate NY | Registered: July 02, 2013Reply With QuoteReport This Post
DRR Pro
Picture of rusty
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must be correct,has he tried more timing


honesty is the best policy,insanity is a better deffense
1.036, 6.16@ 224

 
Posts: 1408 | Location: texas | Registered: February 17, 2006Reply With QuoteReport This Post
DRR Sportsman
Picture of Richie
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Jamie, What coil does he have??we could do a heat gun test if it's a HVC-2.
 
Posts: 255 | Location: Windsor locks Ct. | Registered: November 25, 2004Reply With QuoteReport This Post
DRR Pro
Picture of Footloose
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Wonder what would happen with the cam advanced 2 degrees?
 
Posts: 1921 | Location: in a van down buy the river | Registered: September 07, 2002Reply With QuoteReport This Post
DRR Sportsman
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I’m pretty sure he tried the timing at 38 and it didn’t like it.

Not sure on the coil Richie but I think he replaced that too.

Footloose not sure where the cam is in now but cam timing was one thing changed this past winter. But I’m not thinking a couple degrees of cam timing is the problem.
 
Posts: 713 | Location: Upstate NY | Registered: July 02, 2013Reply With QuoteReport This Post
DRR Sportsman
Picture of TD3550
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For what ir's worth. Can you post the dyno sheet from the boys in NY?
 
Posts: 1409 | Location: Under a Truck | Registered: August 23, 2013Reply With QuoteReport This Post
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