We are currently running on the new domain and server: www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

CR with E85 on boost?

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
User avatar
SWR
Guru
Guru
Posts: 2791
Joined: Sun Jan 29, 2006 5:39 pm
Location: Norway
Contact:

CR with E85 on boost?

Post by SWR » Thu Mar 22, 2007 10:32 pm

As the meth cars run high CR's with big boost on top, (I searched and found a 1.8-liter Honda running 13.8:1 with 35lbs. on top), I'm now wondering if a higher CR would be benefical on an ethanol fueled car running up to about 25psi?

Ethanol is technically alcohol and has a serious cooling ability,just like methanol,so given that E85 likes about 8:1 AFR (Meth 5:1(?) and gas 12:5.1) would a CR in-between the low 7:1 for gas and the high 13+:1 for meth be benefical? Like 10:1 or so?

Opinions welcome...verbal bashing is not. (I've had a hard day) :)
-Bjørn

"Impossible? Nah...just needs more development time"

Doug Schriefer
Expert
Expert
Posts: 866
Joined: Tue Jan 18, 2005 2:46 pm
Location: Lake Lanier, GA

Post by Doug Schriefer » Fri Mar 23, 2007 8:42 am

E85 runs about a 9:1 AFR. With the extra cooling benefit, increasing the compression will help produce more power as long as you don't exceed the capability of the 105 (+/-) octane.
Doug Schriefer

Stevespeed
Pro
Pro
Posts: 493
Joined: Sun Oct 30, 2005 1:25 am
Location: Phoenix AZ area

Post by Stevespeed » Fri Mar 23, 2007 11:40 am

Need to know the application. For say drag only you could stay lower in the static compression and take better advantage of cylinder filling with more boost. But for a street car, increasing the static compression will limit the amount of boost but provide major benefits in driveability.

User avatar
SWR
Guru
Guru
Posts: 2791
Joined: Sun Jan 29, 2006 5:39 pm
Location: Norway
Contact:

Post by SWR » Fri Mar 23, 2007 1:19 pm

It's a street/strip Volvo 850,with bias to street use,I reckon 80% so. Being a 600hp+ FWD drivability is an issue... And,we're trying to get the most hp with the least boost,so we'll try to stay below 22 psi... The "norm" here is (for gas) 8:1 or less and 30+ psi boost,we're trying to go for higher static CR due to fairly long cams (high rpm) and restrict the boost somewhat. I'm just curious if close to 10:1 would be considered high with regard to the fuel. I know 10:1 on gas with boost on top is pushing it,but I'm not sure how the ethanol reacts..
-Bjørn

"Impossible? Nah...just needs more development time"

User avatar
SWR
Guru
Guru
Posts: 2791
Joined: Sun Jan 29, 2006 5:39 pm
Location: Norway
Contact:

Post by SWR » Mon Mar 26, 2007 2:32 pm

Just gettin' to the top... :wink: ...still looking for info.
-Bjørn

"Impossible? Nah...just needs more development time"

Stevespeed
Pro
Pro
Posts: 493
Joined: Sun Oct 30, 2005 1:25 am
Location: Phoenix AZ area

Post by Stevespeed » Tue Mar 27, 2007 1:00 am

I think 10:1 would be a good place to start. Maybe try to monitor for detonation with something like a J&S Electronics unit.

pdq67
Guru
Guru
Posts: 9568
Joined: Thu Mar 04, 2010 8:05 pm
Location:

Re: CR with E85 on boost?

Post by pdq67 » Fri Jul 31, 2020 3:46 pm

I'm sorry, another way old thread.

pdq67

Orr89rocz
HotPass
HotPass
Posts: 1947
Joined: Sun Sep 28, 2008 9:25 pm
Location:

Re: CR with E85 on boost?

Post by Orr89rocz » Fri Jul 31, 2020 11:12 pm

Seen 11-11.5:1 work ok. Most run 10.5-11 ish.

Lsx 10.8:1 with 30 lbs boost went 7.17 at 197 at 3280 lbs

My bbc is 10:1 on 19psi so far its Around 1600 whp

jed
Expert
Expert
Posts: 719
Joined: Tue Nov 18, 2008 4:18 pm
Location: Dallas

Re: CR with E85 on boost?

Post by jed » Sat Aug 01, 2020 9:23 am

What happened to SWR???
I always enjoyed reading his posts.

Post Reply