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Dragster doesn’t run what it should
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DRR Sportsman
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Can you remove the throttle stop from the car just as a test to eliminate it? Maybe worth a try. Reason I bring this up is had an issue with my car where suddenly in fall I couldn't get it to run 10.90 no matter what. Earlier in summer was no problem. Turned out to be low voltage at the stop. Stop worked perfect in the pits but would not open up on track.

This message has been edited. Last edited by: Wooley,
 
Posts: 497 | Location: Going to or returning from the chipmine. | Registered: July 01, 2011Reply With QuoteReport This Post
DRR Top Comp
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Here's what you could do to speed up the process of elimination, eliminate all variables. Put the 7.47 converter back in your buddy's Ed Quay dragster. Pull the leave chip and deck it on the trans brake. If it stalls 1,000 rpm less than behind your wife's engine ,your buddy's shafiroff 565 is making 700hp. If it stalls 300-400rpm less, it is making 875hp as the dyno said it did.

This message has been edited. Last edited by: Mike Rietow,
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
DRR S/Pro
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The cam is a 7-4 swap so are you sure you got the wires on correctly.
 
Posts: 2591 | Location: at the track | Registered: May 09, 2007Reply With QuoteReport This Post
DRR Pro
Picture of TORQIN
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^^^^^^???
 
Posts: 1754 | Location: Houston, Tx. | Registered: November 27, 2008Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
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One dead cylinder will slow you down 2-3 tenths or more and 10mph

My first time out with my last Terminator on my 509 , I had one plugged nozzle.

Car ran 8 teens at 162-163 and I made a number of runs that day.


Found the plugged nozzle and the following week went what it should have ....well into the 7’s at over 170.

James Monroe told me exactly what to look for and he was spot on.

I had made some new lines and #7 injector had a big hunk of debris in it.

So you might just have one cylinder down for some reason even though it’s not injection .
 
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
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quote:
Originally posted by TORQIN:
^^^^^^???

If the firing order on cam is swapped then you got to make sure your firing order you hook wires up to matches. I doubt that’s the issue but just throwing it out there.
 
Posts: 2591 | Location: at the track | Registered: May 09, 2007Reply With QuoteReport This Post
DRR S/Pro
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I just fixed an issue like this last year. I built my 540 new 5 years ago and it made 884 hp on dyno which had me believing 8.4s in my old ride but never came close. I pulled the motor and installed in new car and it went 8.5s at best and was 100 lbs lighter. After popping head gasket for unknown reason at last race of the year I pulled motor and ended up boring it to 548 and it dynod at 900 hp. I sent ignition box back to MSD and installed new plug wires and that’s all and the car picked up three tenths in 1/8, haven’t ran a 1/4 pass yet. I don’t know if it was bad wires but do know I had a box issue. 16 horsepower doesn’t gain you three tenths in the 1/8 and yes I have been told that dyno is conservative.
 
Posts: 2591 | Location: at the track | Registered: May 09, 2007Reply With QuoteReport This Post



DRR Pro
Picture of TORQIN
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I was agreeing wit ya green one! Did look confusing...
 
Posts: 1754 | Location: Houston, Tx. | Registered: November 27, 2008Reply With QuoteReport This Post
DRR Sportsman
Picture of Bad News
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Never have seen a conventional headed engine on gas make any power at 35 degrees of timing.
My own experience running engines on dynos for more than 10 years.
You cannot just put more timing into it without working the rest of the combination as well. Fuel,cam timing.
And cam size as well, without a lot of static compression and a large @.050 cam most engines will be sick, they show good power but will not accelerate worth a crap.
An 588 "engine with a 38cc dome used 37 degrees, a 598 with a 42cc dome used 38 deg, a 496 with a 48cc dome used 39.5,but the flame pattern on the big dome combo sucked.
 
Posts: 868 | Location: ft laud | Registered: September 02, 2004Reply With QuoteReport This Post
DRR Sportsman
Picture of pentastarrail
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Start checking the easy stuff first.

Sticking brake calipers
Check Valve lash
Kinked/restricted fuel lines (I know you stated he changed them but I would double check)
Check/open/enlarge fuel cell vent
Check/change fuel, i.e. borrow 5 gallons from a friend
Heat gun on headers to see if all tubes have heat
Swap batteries with a known good one
Check for swapped ignition wires
Change rotor/cap/wires
Disconnect alternator if equipped with one
Does he have steam roller tires on it/swap to smaller ones
etc

If none of the easy stuff finds anything then he needs to dig deeper:
check all grounds/add more, i.e. one to each cylinder head, etc.

Frown


Man was not built to fly ... That's why he built HEMI's

Frank Zeffiro
ALIAS -- BIG KAHUNA
 
Posts: 955 | Location: Winchester, Connecticut | Registered: September 20, 2002Reply With QuoteReport This Post
DRR Top Comp
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This is an old school tall deck 540 with a set of Dart 360's I did for a guy. We knew 15 minutes after it was fired, it would run 7.70's by bolting a converter behind it that had been 7.70's behind another 540 we had in a different Ray Miller dragster, by comparing the observed stall on the TB w/no chip. Which was the same 6600 stall. Both cars run within a few hundredths of each other,both 4 link dragsters.

It's the easiest most efficient path OP to eliminating variables. Check the power with the 565 sitting in the frame rails. If the 7.47 converter stalls 1000 rpm less behind the shaffirof 565, it's making 700 hp. If it stalls 300-400 rpm less it is making 875 hp as the dyno said. It'll tell you exactly what it'll run before you get to the track.

32 - 33 degrees timing.

 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
DRR Sportsman
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Thanks for all the replies. Yes it has a 4/7 swap cam, I verified the wires myself last year but not last weekend. Has a new distributor and I’m pretty sure the wires are new too.

As far as the timing I think Shafiroff wanted him to run it st 41 or 42 degrees which sounded like a lot to me but all of my stuff is on alcohol, 34/35 degrees.

Frank, I like your suggestions of fuel cell vent and others. These are ideas that haven’t been tried yet which is exactly what I was hoping for from this post.

Jamie
 
Posts: 721 | Location: Upstate NY | Registered: July 02, 2013Reply With QuoteReport This Post
DRR Sportsman
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quote:
Originally posted by Mike Rietow:
Check the power with the 565 sitting in the frame rails. If the 7.47 converter stalls 1000 rpm less behind the shaffirof 565, it's making 700 hp. If it stalls 300-400 rpm less it is making 875 hp as the dyno said. It'll tell you exactly what it'll run before you get to the track.



That's a good test but assuming my wife’s car makes about 950, you think a 75 HP difference will be 3-400 stall RPM difference? I think it would be more like 100 RPM different.
 
Posts: 721 | Location: Upstate NY | Registered: July 02, 2013Reply With QuoteReport This Post
DRR Top Comp
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quote:
Originally posted by 183N:
quote:
Originally posted by Mike Rietow:
Check the power with the 565 sitting in the frame rails. If the 7.47 converter stalls 1000 rpm less behind the shaffirof 565, it's making 700 hp. If it stalls 300-400 rpm less it is making 875 hp as the dyno said. It'll tell you exactly what it'll run before you get to the track.




That's a good test but assuming my wife’s car makes about 950, you think a 75 HP difference will be 3-400 stall RPM difference? *I THINK* it would be more like 100 RPM different.


*No sir, 300 400 rpm different as I said. I accounted for 950 hp, as you have now authenticated.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post



DRR Trophy
Picture of deadon1578
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Maybe something to check, are you using your timing light or his? Your stuff runs good, so I would think your light works correctly. Just a thought I have seen this many times with a dial light on MSD
 
Posts: 47 | Location: md | Registered: July 23, 2013Reply With QuoteReport This Post
DRR S/Pro
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I am on gas and only running 35* timing. Took motor off dyno and bolted in car and never tried anything else as I was happy with it.
New wires don’t mean they are good, check them all with meter or take a set off a friends car and try. Trust me on this.
 
Posts: 2591 | Location: at the track | Registered: May 09, 2007Reply With QuoteReport This Post
DRR Trophy
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Have you looked at the fuel system ? If you have a restriction or a weak pump it can make it perform poorly.
 
Posts: 35 | Location: texas | Registered: February 22, 2008Reply With QuoteReport This Post
DRR S/Pro
Picture of SCDIV1
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35-36 degrees is where it should be with good fuel

I use 35 degrees timing and 116 Sunoco or VP-X16 with 15-1 compression...

I agree with Mike about stall checking it....a perfect idea to indicate TQ/HP

You're basically using the converter to measure the engine...

Never did that but its a great idea.

Just do it safe !!!!.....and only for a second or two....
 
Posts: 2733 | Location: Where ever I am, I'm here and it's me | Registered: March 15, 2007Reply With QuoteReport This Post
DRR Top Comp
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If it were me and I didn't have the capability to accurately detect a problem with the transmission, I'd run not only the 7.47 converter on the deck to verify the shafiroff 565 power in the frame rails, I'd stick the transmission out of the wives car in it too in order to eliminate that variable. The Ed Quay dragster could have spun the stator tube. That would make the dragster slow no matter what converter you stick in it.

First thing to do though, is verify the thing is making power sitting in the car. Put the 7.47 converter and transmission in it and deck it on the converter. If the 565 is making 875 hp or thereabouts it'll stall 300-400 rpm's lower than with the 950 hp 7.47 power.

If The 565 ain't making power in the Ed Quay dragster frame rails, then you start looking around for why.

It's either that or break out the credit card and start guessing.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
DRR S/Pro
Picture of Lenny5160
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Using the 'K value' formula for torque converters, a difference of about 65 lb/ft will change the stall 300 RPM.


Tony Leonard
 
Posts: 3164 | Location: Inver Grove Heights, MN | Registered: March 18, 2004Reply With QuoteReport This Post
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