LOST 10mph AND ABOUT 6 TENTHS

[Kenney Kelley]

Originally Posted by Lee Jordan (3223) A/S

Is the chassis still lose? Are all the wheels free, brakes bearings? What about the rear end? Could it be getting tight and slowing the car? Just something else to think about.

Lee.

It might be time to check the Rubber brake lines or Stainless Steel hoses they might look good on the outside but swollen on the inside. I've had to change them on my pick-up truck so i know they go bad. Kenney Kelley

[Bill Marshall]

Originally Posted by Jeff Niceswanger

To slow down that much, and not have a miss, or a bog and not blow up quickly, has me thinking the timing is backing up on it. Somehow.....We had a bad transmission last year after the filter gasket became unseated and lost .13, but our MPH never budged, and your loosing both. That's a hundred horsepower your dropping. Do your headers look like they are getting hotter than normal? Like its baking the coatings ect?

Hey Jeff how you doing. I am one of the guys working on this car. The car sounds good in the pits and going down the track. Headers look fine so i don't think it's going lean. To be honest it's driving us crazy and thanks for the suggestion keep them coming BTW how's your brother and Amy doing

[Don Kennedy]

Originally Posted by Bill Marshall

Hey Jeff how you doing. I am one of the guys working on this car. The car sounds good in the pits and going down the track. Headers look fine so i don't think it's going lean. To be honest it's driving us crazy and thanks for the suggestion keep them coming BTW how's your brother and Amy doing

have You done a leak down test ?

[SSDiv6]

The grounding subject has been brought up before.

Due to many possible issues, when wiring a race car, especially with EFI and electronics, you should avoid grounding to the chassis and/or engine. The best approach is a single grounding location for all the electrical and components, directly to the battery ground.

Since several ground points will creates a ground loop it is probably the reason why the car that was mentioned earlier magnetized.

You are asking the chassis and engine block to carry electrical loads and DC power requires to travel both ways, positive and negative. When you have a single point for all the grounds to the battery you are minimizing the chances to have a grounding issue.

When you have a ground loop, most electronics do not behave properly because the reference to ground is different and can make a sensor output measure incorrectly.

A friend of mine that builds chassis cars such as Top Sportsman and Comp Eliminator cars, had issues with some of the electronics on the new cars and he kept adding grounds. After he called me to ask about the issue, I suggested he used a single point ground. After doing so, all the issues went away.

Just remember, in the early days, we had carburetors and points distributors, and later on, electronic distributors. Nowadays, the cars are loaded with all kinds of ignition boxes, EFI and electronics, therefore, the electrical power demands have increased exponentially and just adding additional or higher voltage batteries does not solve the issue. Many chassis cannot ground properly because of corrosion, paint, rubber isolators, etc...

Although I do not support the product they sell, the link below has some great information and guidance about race car electrical systems.

"https://moretraction.com/2018/12/31/2416/"

[Bill Marshall]

Originally Posted by Don Kennedy

have You done a leak down test ?

Yes Don we checked every thing including bearings valve springs. etc thanks

[Jeff Niceswanger]

Originally Posted by Bill Marshall

Hey Jeff how you doing. I am one of the guys working on this car. The car sounds good in the pits and going down the track. Headers look fine so i don't think it's going lean. To be honest it's driving us crazy and thanks for the suggestion keep them coming BTW how's your brother and Amy doing

Hi Bill ! Amy is driving John nuts with all the virus stuff. She's absolutely ate up with it and John...is John. It is what it its LOL . But all is well up here.
On this guys car, I had a car last summer (Rich South) that had me look at his Holley system. I found a severe grounding problem. Its a long story but it also had a mismatch of "type verses set up" in the programming of the crank trigger. His car went from a 7 under car to a more than a second under car. Like yours, it didn't miss, didn't run bad, just did not run like the dyno said it was going to. I'm betting your going to find something like I did. Keep lookin

[Bill Marshall]

Originally Posted by Jeff Niceswanger

Hi Bill ! Amy is driving John nuts with all the virus stuff. She's absolutely ate up with it and John...is John. It is what it its LOL . But all is well up here.
On this guys car, I had a car last summer (Rich South) that had me look at his Holley system. I found a severe grounding problem. Its a long story but it also had a mismatch of "type verses set up" in the programming of the crank trigger. His car went from a 7 under car to a more than a second under car. Like yours, it didn't miss, didn't run bad, just did not run like the dyno said it was going to. I'm betting your going to find something like I did. Keep lookin

Thanks for getting back Jeff. This car has is not fuel injected. We did check the crank trigger and have changed every piece of the ignition 3 time. Tell you brother and Amy i said hi

[ss3011]

Originally Posted by Bill Marshall

If the engine ran good on the dyno , then what parts are different between the car and the dyno ? Usually the dyno has it's own ignition box and it's own fuel system . Maybe check these two systems out to start with .

We took the coil and ignition box out of the car and ran it on the Dyno made good
power[/QUOTE]


So the only part that remained in the car and was not tested on the dyno was the fuel system . Not sure what type of pump or regulator you have , but the entire fuel system is in question including the fuel cell and any filters . Also check that the fuel cell has an open vent so the cell doesn't get a vacuum in it while the pump is running .

[Michael Compton]

Had a similar situation as this when I first started in Super Stock in 2007 or 2008. Ended up being the fuel pump. We had a Barry Grant fuel pump and regulator on the car and switched over to the Magnafuel units and all the problems went away. Mine would pop/bang on the big end like an electrical miss when in reality it was lean because of the fuel system. I was running a QJ at the time also.

[Stan Weiss]

Is the car down everywhere in the run or is the early part of the run still about the same?


Stan