383 vortec

[Supercharged111]

shoosh, 11.5-1 compression... that is up there at "race gas only" level. Have you done a compression test on it to see what PSI you are getting? it sounds like a nice build though

Or run 91 and tune it accordingly. . .

 

[L31MaxExpress]

I thought engines generally made more power on E-85 over gasoline.

While you make more power on E85 you need more E85 to make that power. So the horsepower a given set of injectors can support on E85 decreases.

 

[L31MaxExpress]

Or run 91 and tune it accordingly. . .

Agreed, my 383 is 11:1 and cranks 225 psi. Runs nicely on 91 but it has aluminum heads.

 

[Devon 11]

Haven’t done a compression test yet I thought the compression was a little high too for 93 however the machine shop I go to told me it would be fine for 93. Something to do with the ethanol content in gas now a days. Still be a while before I can do a compression test. I still have a decent bit of ordering parts till I’m there. I ordered a pushrod length checker but ended up with the wrong one so now it’s time to order that next lol. It’s going a little slow on progression especially with the holidays and a baby due in the next couple weeks lol. I just wanted to get the bulk of the items done like installing the motor and trans so when the kids here it won’t be hard to sneak off to put on crankshaft sensor. Although today ran into the funniest problem ever I put the flywheel on backwards last night rushing so I had to pull it and reinstall it today. Little embarrassing but at least it was funny

 

[HotWheelsBurban]

Haven’t done a compression test yet I thought the compression was a little high too for 93 however the machine shop I go to told me it would be fine for 93. Something to do with the ethanol content in gas now a days. Still be a while before I can do a compression test. I still have a decent bit of ordering parts till I’m there. I ordered a pushrod length checker but ended up with the wrong one so now it’s time to order that next lol. It’s going a little slow on progression especially with the holidays and a baby due in the next couple weeks lol. I just wanted to get the bulk of the items done like installing the motor and trans so when the kids here it won’t be hard to sneak off to put on crankshaft sensor. Although today ran into the funniest problem ever I put the flywheel on backwards last night rushing so I had to pull it and reinstall it today. Little embarrassing but at least it was funny

It's always good to be able to laugh at our mistakes! Merry Christmas and congratulations on the new baby!

 

[Devon 11]

On comp cams website it said the camshaft works against a restrictive exhaust system. I called them for clarification and the rep said I was fine to run the stock exhaust. I was planning on running long tube headers than run a pipe straight back to the muffler in the pics. I have no clue about exhausts and was wondering if this would be a decent setup or not. Or should I keep them routed the same way they are.

 

[tayto]

Haven’t done a compression test yet I thought the compression was a little high too for 93 however the machine shop I go to told me it would be fine for 93. Something to do with the ethanol content in gas now a days.

Yes! you hear of guys always looking for 100% pure gasoline. Why? ethanol is your friend and helps reduce detonation. it doesn't seem to last as long when stored. I do admit I run "pure gas" in my lawnmower, mainly because I am lazy and don't drain the tank over winter.

I recently built a 350 with TBI heads. Final compression was 10.3:1, quench @ 0.035". I drove all summer with 89 and even tried 87 in cooler weather. No issues thus far.

 

[thegawd]

that's not what I understand. Pure gasoline goes much further than ethanol. ethanol is cheaper but you need more of it to go as far as you would on pure gasoline.

pure gasoline is more fuel efficient and the higher the octane the further it goes.

of course you need to be tuned perfectly for any of these fuels to work optimally.

but when you break it down to basics I believe my beliefs are correct.

 

[PlayingWithTBI]

pure gasoline is more fuel efficient and the higher the octane the further it goes.

of course you need to be tuned perfectly for any of these fuels to work optimally.

I think we're talking about 2 different things here. Yes, pure gas will give you more MPGs but, with higher compression and timing ethanol will help reduce detonation. Pure gas Stoichiometric is ~14.7 where 10% ethanol is closer to ~14.2 so, you'll burn more 10% than pure to achieve the same output. You're both right. That's my opinion, I may be wrong
Seasons greetings!

 

[tayto]

ethanol has been used as a replacement for lead since ww2. lead was added to help reduce detonation aka knock. ethanol ignites at a higher temp than hydrocarbons (pure gas). it also has a higher octane rating. pure gas like i mentioned before last longer and i will even give you that you will get slightly better milage vs ethonal laced fuel.