I think the Drag simulator works fairly well, It was right on for my car with what I had, but I'm wondering if anyone has found the Dyno program to be somewhere in the ballpark.
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I'll let you know when I get my truck dyno'ed, I used DD2K to plan the engine


355
dart iron eagle heads, 72cc, 2.02/1.60
KB pistons 10:1 CR
Dart Sportsman Intake
Holley carb(600cfm?...came w/truck, will upgrade in future)
comp cams XR258HR cam, .480/.487 lift 258/264 dur. 110 LSA


DD2K says 400HP, 450 torque, so we'll see what happens

 

I've used it for several combinations and it comes out really close on HP (within 10 HP) but slightly off on torque. When used with a little descretion. Like don't use roller cam for Hyd. Roller, use cam spec's @.050. etc.

 

Dave, Please keep me posted!!

92RS, That's good to hear

Thanks guys

 

seems awful high for that small of a cam, but if it works out... awesome!

 

yeah dave, that sounds a bit high to me too. no offense hopefully. it'll be a sweet combo though, just not perf. optimized. (IMHO) one question, did you deck that block to get .000 deck height? usually w/typical 4valve relief flat top pistons and 64cc heads will be 10.3:1 or so. Im thinking your prolly more reallistcally around 9.5-9.0:1 CR. in the case of the deck not being cut, you can use .015 head shims instead of the typ. .040 gaskets to help get back some compression. my thought on that combo would be more like 430 TQ but slightly lower HP like 375. what kinda truck is this goin in? daily driver or tow truck or street/strip truck? just curious.

let us know what it puts down anyways though. if you want to, you can borrow my 750DP to test on the dyno back to back w/your other carb. you shouldnt even have to adj. it from how I run it on my Iroc.

chris

 

thats what I thought too

slight dome to the pistons, deck was considered in the selection, so, should be real close to 10:1

thats what I was thinking too

90 full size blazer 4x4, 4" or 6" lift, 35" tires, 3.73 gears,daily driver for this winter, toy after that hopefully

that would be great, I'll let you know when, might be in Jan(I want to do a little break-in first)

 

one ? , on a chassis dyno, is tire size a figure in the calculation? I would think it is, but not sure

 

That is a VERY good question!

However, if tire size affects measured rear-wheel torque, so would gear ratio and torque converter slip. Imagine, a new way to "cook" your chassis dyno numbers: Run a small tire, in first gear. LOTS of transmitted torque!

I'm thinking that it would be a fairly straightforward calculation to measure roller speed, engine speed, roller torque input, then normalize the measured output by re-calculating it to a 1:1 final drive ratio.

--Dan

p.s. I have DD2000, and a whole sheetful of dyno data from my 305. I have a 305 model on the program, but never compared the dyno data to the calculated data. I guess I could always check it out! FWIW, I got 262 RWHP from my 305, which is approx. 300 BHP. We'll see what DD2K has to say.