Heading to the dyno

[blueblazes]

I am heading to the engine dyno room on Fri. for proper tune and numbers on my 496. After reading an article in PHR, I want to be sure I don't get inflated results. Not that I don't trust my builder/dyno man, any ideas on things to request or look for?

[techinspector1]

any ideas on things to request

Go in with a revolver in your belt and tell 'em right up front that you want the truth.

[rumrumm]

There is a 5 per cent variance between dynos--some give higher results, some more conservative results. But as long as the system is set properly, you should get pretty accurate numbers. The guy that ran the dyno on my engine told me that their system gave conservative results, and that magazines used systems that gave higher readings. He told me a customer purchased an engine from Hendrick for circle track racing, and their dyno results showed 35 less hp than the dyno at Hendrick. It's all relative.

[blueblazes]

Yeah kinda what I thought. Although the truck runs real good, I think his expectations are pretty high--700 hp. I am anxious the see the actual #s. Thanks for the reply and I hope our results are conservative.

[Dave Severson]

Doesn't really matter if it's a bit high or low, unless you're just looking for bragging rights, as long as the readings are consistently in error the same percentage. Hard to find a better tool for tuning then a dyno, though. Always figured 3 polls and tuning time on the dyno will yield better results then 3 weeks at the track!

[blueblazes]

I feel that the dyno is the only way to tune for me. There may be as few as 2 trucks or as many as 10 in the mud between our runs so the pit is never the same. No real acurate way to measure your times consistantly. And I agree that the numbers really don't matter....it's bringing home the $$ that really counts! Very few will ever see the tune results anyway.

[rumrumm]

I feel that the dyno is the only way to tune for me. There may be as few as 2 trucks or as many as 10 in the mud between our runs so the pit is never the same. No real acurate way to measure your times consistantly. And I agree that the numbers really don't matter....it's bringing home the $$ that really counts! Very few will ever see the tune results anyway.

X2 on that!

[blueblazes]

Well got about the results that I expected today. Avg HP/567.4 & AVG TQ/574. Peak 655.8 hp@5900 & 632 tq@4800. He did say his #s were conservative so I am pleased with the results. Motor does need more air from 6500 rpms and up to make more power ( he thinks this is due to cam grind since rule require 16" vac@1000rpm) but I really don't want to turn it any harder than about 6800 anyway.

[1gary]

Race teams in all kinds of racing can log results of any given race day,but I do get your point about mud racing and change track conditions.Btw-I worked at the Chevy engine plant in Tonn,NY yrs ago in the dyno rm.Race teams as you know use weather stations,track temps,as much data to try to decipher the how and why for any given run.What interests me is what you guys use for mud racing??.Do you guys use throttle stops,shudder boxes,etc.Honestly I don't know how mud racers handle their track tunes,but I am curious about it.

[pat mccarthy]

i build more mud race engines then drag races engines ..guys i work with seem to go all out all the time.....they are nuts.... just rev limiters and a trans brake and Nos ..that s about it. they may re gear for shorter track for hill and hole class

[blueblazes]

We run a stock class with the vac rule and as Pat says it's all go. We don't spray but leave the at 4500 for a 200' run. Our times are anywhere from 5.2 to 9 sec depending on pit conditions. We weigh 5400 lbs with the bbc and are not allowed to gut or cut. But 'glass bodies are allowed. Go figure....

[rumrumm]

Those are pretty healthy numbers. Now, the proof is in the mud. Let us know how it performs.

[blueblazes]

Thanks and we run Fri. nite. I will post results when we get home. We have two 1st and one 2nd so far running on 7 cyl. and no 1st gear last month so hopefully will be strong. My 20 yr. old son/driver is excited and ready to try it out.

[blueblazes]

Those are pretty healthy numbers. Now, the proof is in the mud. Let us know how it performs.

Well the truck ran very good but the pit was dug to give the small trucks the advantage. Got only 25' before going down and got beat by an 85 hp 'Zuki Samari on 44s that stayed on and went around 180'. Maybe next time.

[Dave Severson]

Bummer, tell them you want some shallow mud, like one pass with a garden hose over some blacktop!!!!!