gimme! (I will scan, reformat, screen-cap, or do whatever else might be needed to put dyno sheets on the web...)

 

This thread confused me a bit, so I went back and checked my files, at work.

Our last "5 speed" stroker made 423.8hp and 464.2ft. lbs. That is with intake in stock configuration and through cats.

I have no idea how to post the actual dyno sheet on the forum. Help?

Perhaps I can send it to someone and they can post it?

 

Gregg,

I can post image files if you need. Just email me at george@jorj7.com

 

Greg G and Louis....you guys should write a book!!

Mark K...you motor is Nickasil coated wtih lw pistons...you should have about a 3% - 5% gain in HP due to lower friction of the nicasil (even over alusil) as welll as lower rotating mass due to pistons, rods and flywheel weights and on a acceleration dyno, it does make a difference.

So I suspect that there is about a 5-7 or so percent to be gained if we know how devek made the motor...add thatto the greg g, louis o tech with a coated block, solid lifters, better springs, etc. and the 600 rwhp barrier will be broken.

Louis motorwith ITB makes 580, Mark A motor with custom manifold makes 515, and Tim d motor makes 515 with stock intake....this tells me there is somethign else going on here and it is worth knowing

So the configuration for a 400 + rwhp usign stock components with minimal, if any porting (mark k quoted a devek engine with tuning and stock (inc 39 intake valves) everything made 420 something) would be:

cams
headers
exhaust
Piston to wall spec
crank to rod spec
crank to block spec
piston ring gap
rod bearing spec
valve to guide spec
head flow
piston weight
rod weight

these is what i am looking for....

plus any other coatings/tweaks??

Anyone...??

Iceman..how do i contact marc or susan?

-dave

 

600 rwhp....never (ever, ever) going to see those kind of numbers from an engine with a stock based intake manifold. Engines are just pumps...they can't make more power than air can flow through the lowest flowing piece. In the 928 case, that is the intake system. No matter who touches it, no matter what happens, the 928 manifold is the flow limit to this engine. He's what I know....and have all the flow data to back up....if someone out there has an engine that makes more than 475hp (naturally aspirated, no nitrous), rear wheels, through the stock (outer dimensions) manifold....they need to go to another dyno that has been recently calibrated and verified, 'cause the dyno that they got that number from is screwed up.

 

Hmm, well, if this is the case, than my stroker would make as much hp as the stock S4 motor i had . (ie 335rwhp) if i didnt have the nicasil. I dont think the rotating mass is any less, in fact it probably is more due to the crank and larger stroke. even still, I dont feel any "blip" throttle differences . on the dyno, the rotating mass would have little effect on hp , wth acceleration rates running over 6-7 seconds from 3000 to 6500rpm. Joe fan and Mark's engine are making the same hp now, in fact, i think mark makes more now and Joes is Nicasil and Mark's is Alusil.
I know Don Hanson motor made close to 450rwhp with the stock intake. I dont think anyone has hogged the thing out to the point where it could be optimized.

If World challenge Vets can get near 500rwhp out of their 5.7 liter motors with that 50% restrictor, I would think that with all the trick race stuff, the 928 stroker could do it too. Im sure it would take a lot of work though! even today, Mark Anderson has a relatively mild cam compared to the race cams available today.

As far as I know, sure there was "devil in the details " with Marc's motors, but with GT cams, big valves and some mild tuning, he got near 420rwhp and up to 450 when it did the extra tuning and some other minor mods. I drove the car at the track and it was a beast! a lot more power than i have today with the stroker and little or relatively no tuning.

mk

 

By Mark Kibort Here's some pics of the manifold I had ported, it is about as far as you can go, it was quite worked over and cleaned up through all the runners.









This manifold design is certainly limited, you are never going to get 600 hp out of it rear wheel or otherwise.
Greg

 

For my intake I hope to use throttle bodies, the intake tract is almost perfectly straight, as such I can afford to go with a smaller diameter, especially if I get the exhaust scavenging and intake lengths correct. The runner I am thinking of is 47.2 mm in diameter and tapers to 46 mm at the throttle body, I can't help this although it may not hurt? The throttle blades are very fine as they are from a bike. I plan to get these throttles on a flow bench in the new year.

Also different bell mouths were tested by Professor Blair of 4st Head Software and he found the ellipse the most efficient design, best flow and less spit back. I am hoping the high velocity will help with the drivability along with Tri-Y stepped headers which I have. Of course the Porsche 928 cams also have a wide lobe separation and as such this will broaden the power curve.

Greg

 

Dave,
The 580 rwhp number for my engine is STD corrected. For SAE corrected the output is closer to 555 rwhp. My block is regular alusil with 944S2 pistons, 968 intake valves with only minor port cleanup. CR is 11.4:1. No magic involved. The main departure from other strokers is the ITB intake and cams. Those items are probably good for 120 rwhp over stock intake and GT cams. The gain is all on the upper end above 4500. The torque is very broad with a peak around 5300 and slight slope down from there. The intent of the design was to maximize the torque above 4500 where the stock intake stroker begins to run out of breath, yet have an engine that was street usable. I didn't want more than 500 lb ft of torque for driveline reliability. Still, I ended up with more toque than I wanted and if I were to do it over I'd choose to reduce the stroke to have about 6.0L. Don Hanson got a little over 600 rwhp from his engine that was similar to mine except his throttles were 52mm instead of 50mm. His air horns were shorter. He had Ti rods and spun it to 7200 rpm.
If you want good stroker performance using a stock intake, extrude hone it and use spacers on the side plates. With GT cams, you might get around 450 rwhp. 600rwhp won't happen with an intake that looks anything like the stock intake.

 

Louis,

I do not believe in magic, but in specifications and requirements.

I do think that if we take your engine, add coatings with nikasil bore and lighter pistons, and thin oil, lwt lifters (if there is such a ting) and I suspect you will have close if not a 600 rwhp engine SAE.

Waiting for greg b dyno report, but after his comments of making the dyno sheet anything he want it to be makes that a bit questionable. sorry greg, but that is how it sounds.

I have sent marc@devek a note, but no answer yet...any phone numbers for him? he may not tell, but I have to ask before i decide to venture in to the stroker game.

The stroker thati can find with stock intakes are few...can someone beign posting their dyno numbers with mods? I want the 928 to look bone stock.

Sterling, you have the highest tech, stock intake stroker out there...what does your dyno look like?

Happy Holidays

Dave

 

Yes, I suppose I could have done some of the coating things. It wasn't done much when this engine was built. Other than to post a high dyno number, I'm not sure why I'd worry about it. As it is now, 1st and 2nd gear are useless for any sort of fast acceleration since the rear tires break traction and I'm not a good enough driver to keep it on the edge. It's all over too quickly. In 3rd, I can get the throttle open and the PSD is active, and traction is ok if you don't mind some side to side wiggle. 4th is solid, but you are over 100 by then. For passing a truck/trailer or big RV at 55, you can be in 3rd pull out and get aligned, roll on throttle. About the time you get throttle wide open you are finished in 3rd, shift to 4th and get on the throttle again. About then you are past the nose of the rig and going 120+. Sometimes, I use 3rd to accelerate to around a hundred, then shift to 4th and hold a hundred until I'm past. Maybe I'm getting too senile, but that is about all I want.

On a chassis dyno, I've found that tires can make quite a difference in the power read. I've found Hoosier slicks to give 25 - 30 hp more rwhp than tries with tread. No dyno slippage, just less rolling resistance with the stiff sidewall slicks. That's in 5th gear with speeds up to 185. Tire air pressure makes a little difference in rwhp, but not a lot. You'll get more top end rwhp using 4th gear than in 5th because of more rolling resistance loss at the higher road speed in 5th.

As for 600 rwhp from a 928 engine with stock appearing intake, won't happen unless the air is mechanically crammed in.

 

Classy and nice! Really appreciate that.

I don't use my own dyno numbers, as I said. I care so little, that my Mustang doesn't even have a printer hooked up to it. When someone else cares, I go to an independant dyno, so there is no chance of inpropriety. How do you get from that to what you said...with your education?

Have fun! Hope you can find Devek.

 

Happy Holidays to everyone!!

Greg...this is a concerning statement.

Greg states: - Horsepower is a funny thing. I can make my Mustang dyno read just about whatever I want it to read...you name it and I can make it happen....so I'm kind of dubious about some of the "silly" claims made out there. I can "tweak" the results so much, that I tend not to even quote numbers, unless they come from the same local Dynojet that we all use...around here....with the exact same calibration, each time. Kind of one of those "independent tests"...if you know what I mean. Now if everyone gathered at the same dyno on the same day...and did the same test....we might have some real data. Otherwise, I just consider it to be a bunch of bench racing, of little value. The other technique we use is pretty simple....bring it on by and we'll run one of ours against it....that pretty much always tell the real story. I think Rob can tell a story or two about running his 380hp stroker against 500hp supercharged things....and it's not a story that the supercharged guys like, very much.

Sorry for reading to much into this, most folks try to calibrate their equipment to a standard...so, please publish your dynojet corrected numbers! Very eager to see them!

Sterling....sorry you still have issues ...I never did...and they are gone...why you still kicking and kicking me too?

Those guys started the 928 performance game, their stuff really worked ..give credit where due.

Thanks for the contact info...you know who you are. I sent an email asking for specific details...lets see what come back.

David

 

How you get from what I said to suggesting that my results are "concerning", is beyond me. Read it again....it's in English and there is really very little room to interpret it many different ways.

Here's what it says, in a simplified form:

Many of the dyno results, both currently posted and posted in the past, are pure bull****.

I have a Mustang Dyno, of my very own.

One can vary the results on many dynos. On my personal dyno, depending on how you apply the load, you can get different numbers. You have to be careful to get meaningful results. (This has nothing to do with calibration, but totally with how load is applied. If one "overloads" a dyno and the engine is de-accelerating, the horsepower results will be very high. I use my dyno for a tuning tool. I pay little attention to the actual horsepower numbers. I pay attention to "steady state changes". There is not even a printer near my dyno.)

For really accurate comparision, I take all my stuff over to a totally independent Dynojet dyno. The numbers are uncorrected from that dyno. (Where is it suggested that I use "corrected" numbers?)

How you get from what I said to any form of inpropriety is beyond my comprehension and I resent you inferring that there might be.

 

Sterlings motor would be close if he had Louie's ITB set up on there, but I don't think he has coated pistons.