High Comp Piston gains on lt-r

[dg26]

ok guys i bought a new high comp 13.5:1 piston for my lt-r but lt-r heads are on backorder right now so its in pieces still but what could i expect for added power with my high comp? 2 horse? i have a yosh exhaust and pim on the way will i be in the mid fifties with those mods?

[dg26]

and i understand that i need race gas i will be running u-4

[dshfearh]

you could probably expect some decent gains. maybe mid 50's. i say that just because i've seen dynos where guys have gotten 50 out of one with bolt ons.

[Ridin' Jesse]

From what i hear its not worth it...I think all the power is getting your FI right mostly for that quad...and Cams.

[tt racer]

I have ran the u-4 in my yfz and you cant run it with a high compression piston. The octane rating is around 96 or something. Im just trying to save your motor.:eek2:

[bwamos]

Aye.. U-4 is actually 92 motor octane.



From vpracingfuels.com
U4
Used in stock and modified 4-stroke applications, as well as stock 2-strokes. Makes up to 6% more power than pump gas and any basic nonoxygenated racing fuel. Passes fuel rules for AMA amateur racing and is also perfect for club level racing, CCS, WERA and AFM. For optimum horsepower and performance, do not store this fuel in vehicle — drain fuel system.

• Color: Clear
• Motor Octane: 92
• Specific Gravity: .718 at 60° F

You should be running VP-110 (purple)
MR8 is the only VP Oxygenated fuel with high enough octane to run a 13.5:1 piston.

I'm not an expert.. but oxygenated fual may be hell on the injection system and pump. You'll definatley have to purge after every use.

[AL Elks]

You can run U2. I run that in my LTZ high compression. Keep in mind though that it's oxygenated and it will coat your exhaust port. Nice power using oxygenated fuel though.

[bwamos]

Originally posted by AL Elks
You can run U2. I run that in my LTZ high compression. Keep in mind though that it's oxygenated and it will coat your exhaust port. Nice power using oxygenated fuel though.

True you might be able to get away with it. Didn't realize U2 was 101 motor octane.

FYI: I am unedjumicated when it comes to racing fuels. ;) I just know 93 otcane isn't going to work with 13.5:1 compression.

[CdaleXtreme]

U4 shouldnt Detonate, But U2 should run a little cooler.

I know there are a few race teams running a little 2-stroke pre-mix in with their oxy fuels.

The Oxy fuel will wreak havoc on your fuel system, and as stated on each drum. DRAIN YOUR FUEL SYSTEM AFTER EACH USE.

It does make better power and more throttle response, but IMO not worth the extra price and hassle.