when do i need higher octane

[huntertaylor98]

whats the highest compression i can run on pump gas

[CJM]

Originally posted by huntertaylor98
whats the highest compression i can run on pump gas

Im not sure, when did people start running on pump gas??? :o


















































Seriously, the kinda of quad you own helps me tell you......

[huntertaylor98]

Don't own one YET just seen a few trx450r at 13:1-13.5:1 and wondering if I could run pump gas

[CJM]

12:1, some can get away with 13:1 depending on what fuel, cam and elevation they are at Most need to stay at 12:1 tho. Those quads with higher compression pistons are setup for race gas only.

[huntertaylor98]

One I really interested in has a wiseco 13.1:1 and has a stage 3 cam the guy also told me if I rejett I would be able to run pump gas

[wilkin250r]

Originally posted by huntertaylor98
One I really interested in has a wiseco 13.1:1 and has a stage 3 cam the guy also told me if I rejett I would be able to run pump gas

He's half right, you could indeed jet it super rich (more fuel than it needs), which will effectively cool the piston and allow you to run pump gas.

Of course, it also kills the power, runs like crap, and fouls plugs. But hey, it's running on pump gas!

[huntertaylor98]

The motor was done by Baldwin it stock bore with wiseco 13.1:1 piston stage 3 hotcam port polish programable cdi and what dyno a 54.3HP

[SpasticR450]

You need higher octane when the engine compression is igniting the gas instead of the spark plug. FACT. :devil: Yet many people run higher octane because they think the so called "race gas" makes them fast. :chinese:

[huntertaylor98]

Originally posted by SpasticR450
You need higher octane when the engine compression is igniting the gas instead of the spark plug. FACT. :devil: Yet many people run higher octane because they think the so called "race gas" makes them fast. :chinese: That just Denation in a nutshell

[huntertaylor98]

Wouldn't rejetting for the 13.1:1 just be a waste because it would make least power than a 12:1

[SpasticR450]

Higher oct just ignites at a higher temp.

[wilkin250r]

Originally posted by huntertaylor98
Wouldn't rejetting for the 13.1:1 just be a waste because it would make least power than a 12:1

Yep.

[huntertaylor98]

Here's a copy of the ad built baldwin race motor with less then 30 hours, houser +2 a arms, lonestar +4 axel, PEP triple rate fully adjustable shocks, rath sway bar, douglas wheels with hoosier front and american racer backs both have been regroved, houser steering stem, custom made aluminum nerf bars, roberts racing rear swing arm, i also have a set of itp front wheels with like new holeshots on them this is one of the fastest quads around i had the frame, wheels and all the other black parts on it powder coated back in february the only thing it would take to b able to motocross this quad is a set of rear tires and wheels and lifting the shocks back up i also have a bag full of different front and rear sprockets and different chains i also have some other parts to this thing laying around this is a nice quad i am selling for way less then is in it $4250 obo do you think it's worth the power lost and would the reliable go down with the 13.1:1

[quad2xtreme]

You don't have to run straight race gas for that compression. You can go 50-50 mix to 93 octane being 100% safe or you could experiment with 1/3 race gas to 2/3 93 octane solution.

Or, change out the piston.

[huntertaylor98]

what octanes would need to be mixed

[FHKracingZ]

I know motor builders in the industry that have ran 15:1 250F dirtibke motors on pump gas and not had any problems and it dynos the same. Also not had any reliability problems.

Just curious on how that works? Can somebody explain?

[guy310]

It also relates to timing. Just like someone already stated, when the engine compression ignites the air/fuel mix before the spark plug does, you need to run race gas. The best thing for you to do is to call Baldwin and ask.

[crownandmonster]

Originally posted by FHKracingZ
I know motor builders in the industry that have ran 15:1 250F dirtibke motors on pump gas and not had any problems and it dynos the same. Also not had any reliability problems.

Just curious on how that works? Can somebody explain?


The piston might claim to be a "15:1" compression, but there are many factors that go into a true compression number. Deck height, cam lift, and duration just to name a couple. It could be a 15:1 piston, but the piston could be like .080" or so down in the bore at TDC so actual compression is probably a couple points lower, just as an example. It could also have a cam with huge lift and duration numbers, thus the valves open more and stay open longer, letting compression out.

[quad2xtreme]

I have what sounds like a very similar build from Mark Baldwin and he highly recommended mixing race gas to me but I would agree to find out the specs and call Mark. Likely he can look up the build if the current owner is the person he did the build for.

[huntertaylor98]

Originally posted by quad2xtreme
I have what sounds like a very similar build from Mark Baldwin and he highly recommended mixing race gas to me but I would agree to find out the specs and call Mark. Likely he can look up the build if the current owner is the person he did the build for. Is Baldwin saying you will get more power or what

[quad2xtreme]

Originally posted by huntertaylor98
Is Baldwin saying you will get more power or what

nope...to make the engine run cooler and prevent burning the valves or piston. You get the extra power from the added compression...not really from the higher octane.

[quad2xtreme]

Originally posted by quad2xtreme
nope...to make the engine run cooler and prevent burning the valves or piston. You get the extra power from the added compression...not really from the higher octane.

In fact, you will get the most power from the lowest octane you can run...that doesn't cause damage to your engine from pre-detonation.

[fearlessfred]

Originally posted by quad2xtreme
In fact, you will get the most power from the lowest octane you can run...that doesn't cause damage to your engine from pre-detonation. x2