Maybe this is a stupid question....but... do I have to run premium with my new mods?

[hotstang_46]

So i just tried driving my car down the block and it was chugging, so I turned around and brought her right home. I'm hoping it's just because i don't have in a tune in her yet.....but.... When the car got layed up because of the blown plug before all my mods it had 87 octane in it.....Is that a possible reason why it's chugging? and even furthermore, do I have to only run premium with all the mods I just did?

Oh BTW 91 is premium here by me

 

[varad]

I dont know what you did to your car but if you have aftermarket heads with higher compression you need to run 93 but it depends on how much work was done with them.

 

[hotstang_46]

sorry, just thought people would know because of my other thread...

Patriot stge II heads, VT stge II cams, bbk shorty's, 75mm TB/plenum, pro chamber

we don't have 93 here though...highest is 91....is the 87 currently in my car causing the chugging feeling or is it more likely the lack of tune yet? it doesn't feel driveable at all right now, not even cruising ...i don't need a fuel pump upgrade or something do i?

 

[saleen556]

When I had the stage 2 cams installed it wouldn't even idle by itself. Get it to a dyno for a custom tune. You can get a tune for both 87 and 91 octane.

 

[04YELLOWGT]

It just needs a tune BAD. An untuned car will do that especially with a head and cam setup. Mine did it before the tune and I just had cams, hell it did it after the tune because I had a crappy tune in it. You can have the car tuned to run on whatever oct. you want but you just have to realize your not going to be able to make as much power as you would with 93oct.

 

[hotstang_46]

alright cool then...I'm glad it's most likely just the tune...draining the tank is a pain in the azz.....

I'll just have to wait until monday or tuesday till I get my sniper stuff up and going properly

 

[the98stang]

It's probably running richer than hell with those cams. Just get it tuned and it'll run like it did before.

 

[jcint]

no need to drain the tank use octane boost.

 

[5spd GT]

A tune will do wonders...

Your running the same static compression I assume (kept your 99 heads, or got 01+ heads)...your dynamic compression may have changed slightly with the cams, but it should not cause you to run any higher octane. It wouldn't hurt though.

 

[hotstang_46]

I'm in the midst of tuning right now with my sniper stuff...

out of curiosity...does anybody have some type of idea what type of actual HP difference there would be between a tune that is optimized for say 87 octane vs 93......

even though we only have 91 here in cali

 

[thomas91169]

seeing you can run more timing and/or leaner fuel curves with 91 or 93 as compared to 87 octane, on a stock to bolt-on setup that can get you a few hp/tq across the entire spectrum. on a more serious setup it can do even more.