Worth upping compression on Novi2k combo?

[RocketCouch]

I have a 4.6L 2 valve that was built a while ago and running JE pistons with 8.5:1 compression. The car has a built bottom end, Paxton Novi 2k, all the supporting mods, running 17# of boost on California 91 octane pump gas.

I have been told these engines, especially on a centrifugal blower like higher compression like 9.2:1. Would it be worth bumping up compression? On the California pump gas is that going to be "too aggressive"

I am already planing swapping to MPH blower cams (to replace stock PI cams), either a re-port on PI heads or the Trick Flows and swapping to a blow through set up with an air to air (replacing Vortech water to air).

Thoughts? Any help is appreciated!

 

[AntiHeightPunk]

i dont think going up a little in compression will be worth the trouble, i would however do cams

 

[61mmstang94]

More compression would be great, but remember you will be running pump gas most of the time and the lower the compression the safer you're going to be.

Who are you going to have tune the car? I would speak with them and ask them what they want you to limit it to and go as high as they reccomend.

 

[01GTvert]

Any help is appreciated!

Upping the CR would be a great idea, but why do it the hard way (engine rebuild) when you can do it the easy way (BIG crank pulley and little blower pulley). Pulley dat bitch DOWN!

 

[97desertCobra]

Talk with an engine builder and your tuner. Depending on how much you are willing to spend the trick flow heads are better in unported form than ported P.I. heads, quite a bit better. Going with a different head gasket can increase the compression a little along with milling the heads.

Upping the compression is worth it to me. Just go a little conservative on the tune. I'm looking to stay around my stock compression 9.85.1 when I rebuild.

 

[meaty mac]

Talk with an engine builder and your tuner. Depending on how much you are willing to spend the trick flow heads are better in unported form than ported P.I. heads, quite a bit better. Going with a different head gasket can increase the compression a little along with milling the heads.

Upping the compression is worth it to me. Just go a little conservative on the tune. I'm looking to stay around my stock compression 9.85.1 when I rebuild.

Just getting the TF heads would do the trick- they come in either 38 or 44 CC

 

[61mmstang94]

I'm just curious because I don't know anything about the TF heads for the 2v. How do they flow compared to a set of stock ported 2v heads?

 

[97desertCobra]

I'm just curious because I don't know anything about the TF heads for the 2v. How do they flow compared to a set of stock ported 2v heads?

I was reading in MM&FF about the TF heads. I dont have the issue infront of me to give you an exact quote, but in a FI application the TF heads made about 40rwhp more than the ported P.I. heads did. They flow way better on the intake side. It looks like it would be about 60rwhp difference between the TF heads and stock P.I. heads. Maybe someone with the issue handy can help me out and get more accurate quotes from the issue. It was rather impressive none the less. Certainly a game changer for the 2v's. With these new heads they can start to stand up against the 4v heads. I can only imagine the gains to be had with ported TF heads. The only thing I remember seeing the new heads lack is what the 2v's have always lacked, exhaust flow. But they were still better then stock.

Makes me wonder if changing the design of the 4v heads to a similar TF design would yeild similar results.

 

[White04GT]

Hmmm I don't know why you went with that low of a CR on a 2v let alone on a car that has a centri blower on it....It had to of lost some low end power which the 2v already lacks, I could understand a little bit more if you were throwing a twin screw on it, I am and I still went with a higher CR then that just because I don't want to have to run so much boost to make the power I want, but ya I agree with the others swap the heads out for some TF Heads and throw on some blower cams and make some real power

edit: oh ya another easy fix, is run a smaller puley. I would reccomend a 8 rib set up if you don't already have one.

 

[RocketCouch]

The car build started in 2000 when the modular world wasn't as developed or understood as it is today. I followed what others told me and didn't do any research. Wow did I learn my lesson!

I have ported PI heads on there now but I don't think they are ported very aggressively. By swapping to the Trick Flow pieces and going with the smaller CC head how much "should" that increase compression?

And throwing on a smaller pulley will just increase boost which is already pullied for 17#s. More boost = more heat correct? I'm still looking for better low end power before the blower is producing full boost. And yes, it is an 8 rib set up. Haven't had any belt slip issues since then

 

[RocketCouch]

Swapping on the Trick Flows wouldn't change compression if I'm understanding correctly. I already have PI heads which are the 38 cc head correct? Going with a larger cc head would decrease compression correct?