Piston Noise...

[Cheromaniac]

I am speaking of crankshaft power not rear wheel hp.

So was I.

[superstingray77]

Cool just didnt want you guys thinking I had completely lost my mind. That newcomer racing engine is built to similar specs as mine and hit 350 HP but using a carb and some really nice flowing headers so id be shocked if I made 300 to 315 in the truck. You think the limiting factor is the head or intake? I know non crossflow means more intake heat. But with the flow numbersmy head.has.and.cam profile I would expext the head to be capable of more?

[Cheromaniac]

You think the limiting factor is the head or intake?

If you still have the stock intake, that's definitely the limiting factor. The runners have a small cross-section and aren't conducive to high rpm horsepower. It might not be a bad idea to either get a junkyard '91-'98 intake manifold (you'll pick one up for next to nothing) and start modding the hell out of it, or fab a custom manifold of your own.

[superstingray77]

Funny I was thinking the same thing, why the 91-98 is that one better to mod than the 99 up?

I looked at some multi-throttle body setups on some of the top speed racer forums, (those guys are really creative) makes me wonder what we could "create" for the Jeep inline. Not having water in the intake makes mods much more simple than any of the V8's -V10's I have done in the past. I would imagine that a 3 TB setup would be ideal with 1 TB feeding 2 cylinders tied with with either a linkage or preferrably a common shaft to keep them synced up. Ultimately getting one made out of a composite would be neat to prevent heat soak, but wonder if our headers would just melt it down or distort it over time.

My current TB is bored out to 62mm but all the 90 degree turns the air seems to have to make just cant be good, I am still using the paper filter and stock airbox. I have a bunch of conical filters around from old supercharger projects etc. I think i can fab up something using the stock WJ hat and just build a modded snorkel and filter setup from there then seal it in like you did to block out the engine heat. I saw your heat shielding on the bottom of the its holding up fine i presume? I did wrap and coat the headers which dropped IAT immensely but with outside air at 96 my IAT is still reading about 104-109 depending on throttle load/flow.

Any clue what formulas might be helpful for determining runner length and calculating the pulses / reverberation etc to try and prevent one cylinder from potentially robbing fuel/air from another? I have seen some of the "created" intakes have this problem on inlines and the guys ended up having to move the injectors farther back in the airstream and set them to batch fire mode to "make it work" those mods do not seem like performance gains to me.

Thanks again, btw all your info has been a huge help in this entire project.

[Cheromaniac]

Funny I was thinking the same thing, why the 91-98 is that one better to mod than the 99 up?

I looked at some multi-throttle body setups on some of the top speed racer forums, (those guys are really creative) makes me wonder what we could "create" for the Jeep inline. Not having water in the intake makes mods much more simple than any of the V8's -V10's I have done in the past. I would imagine that a 3 TB setup would be ideal with 1 TB feeding 2 cylinders tied with with either a linkage or preferrably a common shaft to keep them synced up.

The '91-'98 manifold is easier to cut up and modify for a 3 TB set-up. If you make the runners shorter and wider, and somehow move the flanges for the TB's to the side so that air has a straight shot to the cylinders, it would be a great performance set-up. It would also require a lot of work and creativity.

[SilverXJ]

Ultimately getting one made out of a composite would be neat to prevent heat soak, but wonder if our headers would just melt it down or distort it over time.

Do a two part manifold. First 4-6" near the headers out of aluminum, and the rest out of composite.

I looked at some multi-throttle body setups on some of the top speed racer forums,

Just some ideas: http://www.ebay.com/itm/JEEP-AMC-MoPar- ... d1&vxp=mtr

My current TB is bored out to 62mm but all the 90 degree turns the air seems to have to make just cant be good, I am still using the paper filter and stock airbox.

I think you will see a benefit in going with a cone filter, and eliminating the accordion tube. If you make the tube of aluminum there is a sock type wrap you may want to look into.

I saw your heat shielding on the bottom of the its holding up fine i presume? I did wrap and coat the headers which dropped IAT immensely but with outside air at 96 my IAT is still reading about 104-109 depending on throttle load/flow.

Yes, the heat shielding is holding up fine. I was concerned about it falling off so I did fab a steel mesh basket sort of to hold it up in case it did. Wrapping the headers does lead to damage on the headers. I had mine coated instead. I wonder if coating would help prevent damage from wrapping.

Any clue what formulas might be helpful for determining runner length and calculating the pulses / reverberation etc to try and prevent one cylinder from potentially robbing fuel/air from another?

I believe the software pipemax does just that.

[6TIME]

That motor sounds good! What are you doing to keep the computer happy with the choppy idle?

[superstingray77]

Running a custom tune using SCT with full open loop only. With a lumpy cam close loop in the idle range will drive the narrow band 02 sensors nuts. Fuel ratio would dance all over the place. We setup the idle around 16:1 locked. Which is great and keeps it clean no stalls etc in or out of gear with the AC on or off.

I had wanted a closed loop cruise mode for max econ, however with the overlap it also trips the 02 into thinking the mix is leaner than it is and again AFR dances around. So the entire setup is Open loop only. Works really well thus far, had some 40 degree temp changes here in Austin this past 2 wks and the mix has remained stable.