Well ..............went to the wheel dyno now I have questions

Bruce is right. Mine was suppose to be around 3,250 stall. On the brake it goes to 46-4700!! :eek2:

 

Alan W.,

When chatting here on the net and doing some bench racing all must understand (myself included) that what is said is vague. I dont care if we chat about engine dynos, chassis dynos, power speed calculators... you name it! The only thing that matters is the ET slip. Even that can be misconstrued because the guys that run on the east coast at sea level (or below sea level) have much more of an advantage than someone who races in Colorado where its 3500 feet above sea level.

But anyhow I understand what you are stating. I am not a betting man... BUT... if I were Pete Rose..... I would be willing to bet that if Mike removes 500 lbs from his car it would run about .50 quicker in ET. A great example is my 523 vs. JWs 525. They are both comparable engines (excepts his made more than 5 passes) and are both in the same body style car. Mine is 350 lighter and to date has run about .35 quicker. Now.. that may change next year when Jim gets the bugs worked out but still similar. My car and Doug Hecker's car both weigh the same with driver and run within a tenth of each other.

All I was saying is if you take a 3000 lb race car and ADD 1000 lbs to it.... it will probably slow up about 1 second. Or if you take a 4000 lb race car and remove 1000 lbs it will go about 1 second quicker. Again.. just a rule of thumb.

It would be quite different if you were going from a 4000 lb Buick Skylark to a 2500 lb dragster.

Take Care

 

Personally I will be building a 2500 lbs street legal race car soon. I was hoping that I could get into the 9s with that!!!:Brow:

 

Bruce,

CORDS SHOWING.... Now that is getting every pennies worth out of your slicks!!!! Aslo.. if you want a better front spoiler just slam the front bumper to the ground.:grin:

 

weight

You had better be in the 8's with that much wieght reduction:laugh:

John, FWIW:

Here in Denver the track is at 5800' with DA's in the 7500' range regularly. To sum it up in words: The air up here SUCKS!ou:

Jim

 

Just a thought...

I was thinking about this Mike. God knows I'm no expert, but I had an idea on pinpointing your issue.

It strikes me that if you are losing about 300 horses between the crank and the tires, all of that energy is getting wasted somewhere. That's a lot of energy to lose, and it will probably show up as heat right around where the loss is ocurring. I mean, unless something breaks, the only way that the wasted energy will really show up is heat, right? If it's friction losses, it will make heat. If it is the convertor slipping like crazy, it will heat up something, probably your fluid, maybe even the bellhousing. If part of your tranny is going, you will probably see a hotpot on the side of the case near where it is going out. Heck, if it's your rear end, it should heat that up too.

I'd go tearing around your neighborhood in a spirited manner (not that you would do that ordinarily ) and then get underneath the car as quick as you can afterwards with an infared pointer thermometer and see what's hot. Spot-check the whole driveline from the motor to the wheels (it should only take a few minutes) and see if you have any hotspots. For that matter, you could probably just feel with your hands. I'd bet the hottest part of your driveline is where you are losing the most power.

It might tell you nothing, but it might give you a clue on where all of those horses are hiding. Like I said, just an idea.

- Freed

 

Mike, I'd bet it's your convertor. Don't worry about the diameter. I'm running an 8-inch and it's locking up just fine up top! I had Coan build me another convertor and, hoping to drop some rpm, I suggested a 9-inch and told them I wanted 5600 stall (which is what my 8-inch is) but that I wanted it tighter on top end. Well, when I got it in the car, it ran virtually identical to my 8-inch. I mean the same stall, same ET, the same mph, the same rpm!! I sent it back to Coan and called them up and I said: "Hey Coan, WTF!" They said it's likely that I've already got an 8-inch that's as efficient as they come...so you're not gonna get any improvement just because you go to a larger convertor! That only works if there is a problem with the smaller one. They said if I wanted to drop the top-end rpm, I should drop the 4.56s down to 4.30s and they would change the impeller in the 9-inch convertor to make up for the loss on the bottom end. I haven't put it back in since the gear change so the jury is still out on that. One thing to keep in mind regarding convertors is a piece of wisdom that Scotty gave me....No matter whose convertor you buy, consider yourself lucky if you don't have to send it back for adjustment at least once! Good Luck!
John, two small things I'd like to clarify:
1. Your car weighs 100 lbs less than mine race-ready. My car is lighter, but my driver is (much) heavier!
2. There is only 3 hundredths between us. (as if you didn't know! :laugh: )

 

Mike,

While at the PRI show I chatted with several of the converter guys. This is a great show to talk to the tech guys because they are not inundated with phone calls so they will chat as long as you wish. But anyhow all of the converter tech guys told me with todays technology a combination like mine should see 3 to 4% slippage. My converter is a Trans Specialties. I talked with Paul at Trans Specialties while at the show and he said the technology is improving everday with converters therefore the converters are becoming more effecient. He also said the use of a Moroso Power Speed calculator for checking % of slip is very accurate. Provided you have the correct data. So it seems there is more ET to be gained in your converter.


Doug,

There are two things that I will never dispute with you.
1. I do weigh less than you!
2. You do have me by .03!

But I thought at one time you had told me your car was 2800 race ready? Sorry for the misprint.

Take Care.

 

John, at one time, my car's race weight WAS 2800 lbs. That was a while ago. Not any more. These last several years, my driver has gotten heavier than he used to be and I've added the external oil pump, the vacuum pump, and a heavier battery. All told, that stuff and my own extra tonnage has added about a hundred pounds to the total. Whatcha gonna do? Right? o No: :laugh:

 

Doug,

OK......I will agree.... But I am willing to bet your wallet is about 100 lbs lighter now!!! :grin:

Take Care

 

It's only money....I'll make more!:TU: