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I was looking at it on my phone so I only read the first couple of paragraphs. From what you've said, I gather you think the 4V heads could do it, but not the stock intake?



I like the Koenigs, although '80's turbos and engine management on an expensive engine scare me. And for that much scratch I could have another rental property...

You may need to find a set of Koenig flares for your car to work with your suspension mods so that you can tuck 335's in the back.

It's a --- bling, bling,bling --- a test rosa, at least it has red heads.

as we tangent a bit on the 4L build that is up for sale by the owner. He's posting the numbers based on Ethanol fuel not pump gas. The engine does have 13.7:1 compression and was designed around running E85 when available. I installed an ethanol sensor so that the ECU can manage the tune on the fly.

There is no way that engine can breath thru the stock filter and gutted CIS box. It's on there to satisfy CA emissions visual inspection. Highly recommended not to run the engine regularly in that configuration. it's starving for air!

There was ALOT done on that build... the only stock parts are the heads and block, everything else is custom or modified. The heads and intake have been modified a bit to flow more but will not match the ability of ITB's, and that would really wake that engine up.

As it is, the engine is NUTS, it revs so fast that it catches you off guard. Pulls very hard in the upper RPM and given the GTS chassis I actually chicken out and have not been able to pull past 7K in 5th. It'll rev to 10k easy, pulls hard all the way to the limit. 1st~4th gears will spin or chirp.

We went thru a lot of headaches with clutches, in the end OSGiken took on the challenge and worked with us to develop a clutch and flywheel for our builds. The clutch is soooooooo nice, twin disk that is rattle free and only makes a slight whirring noise. Next up their working on a diff for us as well. really can't wait to test that out.

Back to Marks project...

Yes, I think they could with good porting, and ITBs or a nice dual plenum intake so I don't see anything wrong with Scott's simulated 503hp but I'm not convinced it can be done with a stock intake that was designed for 240hp....I couldn't do it. But I do engine layout/design in the ways I do it based on my experience, what a lot on what I've read and what I've seen others do....so certainly there are other ways I'm not aware of so....I would love to see an actual dyno sheet on the engine just like I have one friend in particular that REALLY wants to see a real dyno sheet on my engine before he believes the stupid high numbers I'm getting from the simulator for my build. How's that go...in God we trust, all other bring dyno sheets

I went with a different tack on this build early on, I think we may have talked about this off-line Mark. Given that flow numbers are not the best by conventional stds I spent way way more time then I figured it would take to approach it from a dynamic flow model, as in my opinion that's closer to how an engine operates in the real world. So by utilizing the wave model and then focusing on simulated CFD analysis I went about trying to design the best cam lobe profile to get the most power out of this build. Man what a PITA time consuming project that turned into, though it was not for naught. The real fun started when I had to then get a master made so an actual grind could be done. Laurie at Webcam was an invaluable help with that.

Long story short, I believe the cam is the real reason for why this engine has the ability to 'sim' such power numbers. Also after all that I get why cam profile design is sooo highly secretive! it's a major PITA to get and a MASSIVE time sink!

I also want to point something else out, traction. While developing all that power is great fun the weight and gear ratios are, how should I put this.... sucktastic!

Here's a tq/thrust scalar graph I did based on the sim dyno info. Using the vehicle info, tire coefficient, gear ratios etc.. and some maths we can see the 'numbers' of what happens. A quick look at the shift points column and it's very apparent that the tq curve is not that well matched to the gears. The gearbox ratios are truly not setup for an engine producing a lot of power. I did some digging and found that all the way up to the F360 they are all very close to each other in ratios, albeit with an extra gear. So the end result is Mr Toads wild ride!

Sorry its' a PDF guys.

OK made JPG's

We did chat and really peak flow isn't all the telling. A head with weakish very low lift flow but strong mid lift before it's choked by the manifold at high lift, coupled with a aggressive ramp longish duration cam can make a good power curve and decent peak. This is the theory that can lead to the classic "over cammed" low to midrange pig if a ton of care isn't taken and it will never do as well for peak or midrange as a head/manifold combination with good seat velocity at all lifts coupled with a more moderate duration cam with aggressive ramps....but it can be made to work well.

I didn't love any of the cam options I found for my engine either particularly for exhaust but wasn't willing to invest the time to do custom lobes. On the 3.4 setup I had to stay shim over so lift and performance with it were limited quite a bit by that constraint....higher lift shim under would have added a over 30hp and more aggressive porting on the head at the expense of seat velocity would have added another 20-30 to the peak I think....so closing on the estimates for the 4.0 but not there....but as I said I have a bad habit of sticking to the map and looking for good seat velocity at all lifts and calling development done when I hit a flow limit somewhere.



You can zip it and attach or snip it and post as a picture.

Edit...you did while I was typing

Yes, one you make more torque the gear ratios are very unhelpful. I used to start from 2nd gear most of the time with the last blower engine I had.

Ahh shim over with those heavy manhole cover shims! That'll leave power on the table. It also limits lift as well.

This build went to shim under and dropped a bunch of weight. The other 4L I went nuts and gutted weight by more then half! 5mm valve stems, conical spring, Ti bits, etc.. going for 11!

I have to question that traction limit line......unless the tires absolutely suck. I don't have a direct comparison exactly but my first blower engine was right around 300ft-lb torque with...I think they were 245 tires and it worked quite well and that should be pretty close. I had to launch at around 3500 in 1st for best results so it had more than 1st gear liked but just driving it was fine. The last engine that was closing in on 450ft-lbs was ok in gears 2-5 on 285s but 1st was worthless, when the boost hit 10 spi the tires was spinning gently on the throttle of not. Best launch was about 2500rpm in 2nd and gently into 3rd, no spin at all in 4th or 5th no matter what I did.

Clearly it would be less well behaved on 225s but I can't believe they are that much worse unless the tires were hard as rocks????

Yes, the lift was the main thing, the guy doing the actual build didn't want any issues and wanted to stick to around .350 lift....I think I talked him into .360 but that was it.

11 huh? very good for hp if you can fill the cylinders up there. I have a similar valve train on my V12 and enough flow and cam for 11k....but really want to stay under 9500 and an hoping I can make peak power under 9000 becasue I'm a big scaredy-cat