Originally Posted by BC

For some ****s and giggles, I am going to put together an engine with high compression and then boost the hell out of it. This is just a motor of extra parts I have (except for the heads - they are new rebuilt)

So it will be an S3 bottom end, all stock except for some changes to the oil pan distance as well as the piston rings (standardized 951 rings)

The heads will be S4 (3R I think we call them here - from an 89).

So this should net a relatively high (but not for modern standards) CR of 12:1 or so. But I will be boosting it with a Novi 2000 as high as I can go.

The key will be three things, and I think with these three things it will run great and not blow anything up except for everyone's mind:

1) Aggressive cams - reducing the dynamic compression ratio
2) Adaptronic ECU and minute control over timing on each cylinder and injection into each cylinder
3) E85. (high octane, superior charge cooling, different burn and flame front characteristics)

One of my questions is this:

I don't actually think the S3 pistons need to be notched. I think that with the valve timing sorted, the piston never gets near the valves unless something is broken. Any comments on this?

This will be assembled quick and dirty (well, not dirty but surgically clean, but you know what I mean) and the only big hurdle at this point, well, two, are:

1) S4 intake with side plates welded to something so I can do a front mount throttle body
2) The ECU loom (which I am working on)

Originally Posted by andy-gts

BC this is way cool....pushing the limits.....I never realized you actually were running and E85 engine....did you post dyno or was there a thread to follow . I would really like to read about the adventure!!!!

Originally Posted by BC

I have had two cars that I ran ethanol in for a total of 30,000 miles. I learned a lot with them. Those were stock engines and the second was with porkens chips with 36lb injectors.

It really is a great fuel for many reasons.

Originally Posted by IcemanG17

E85 really is a totally different animal than "normal" gas....mostly since its nearly impossible to "knock" E85....so the boost and timing go WAY up and the HP follows with it....

However.....since this seems to be a 2nd level project....I gotta ask WHY.....my 2nd question...what transmission are you putting behind this 26+ PSI E85 boosted project? I ask since NO 5 speed will hold it for very long.....with 5L, 32V with better cams and 26+ psi you are talking SERIOUS HP...like a 5 speed will last minutes power level.... which begs the ???

WHY, what is your end game....do you want to throw down a monster (record) 928 dyno pull...... Do you want to do Mojave Mile? Do you want to do ORR? I won't even ask about track or road course stuff since that is far too much power.... This type of HP on the street is totally silly....

Originally Posted by andy-gts

BC this is way cool....pushing the limits.....I never realized you actually were running and E85 engine....did you post dyno or was there a thread to follow . I would really like to read about the adventure!!!!

Originally Posted by BC

It is different. It's knock limit is something that not many people have found. Since its okay to blow up perfectly good engines now per Tuomo, I'll be testing the limits just like our strangely named rennlist turbo hero. Lol

As to usage - I have wanted to do something similar for a long time. I will take it to places like willow springs and maybe Las Vegas. It has a rebuilt 5spd in it with pieces from Mike Simard for the clutch.

I break automatics, not five speeds. It's my thing. With traction control connected to fueling and retard I know for a fact you can make gears last. I'll not be racing professionally and i don't know anyone who has broken a 5spd just going to DE's and street driving, do you?

But first I mist figure out these valve pockets!

Originally Posted by IcemanG17

Hmm broken 5 speed from DE and street driving.... Honestly I don't think so...they all have been dedicated track beasts.....Louie at 600whp never broke a trans...niether did Tim Dey at over 500....

Originally Posted by IcemanG17

Hmm broken 5 speed from DE and street driving.... Honestly I don't think so...they all have been dedicated track beasts.....Louie at 600whp never broke a trans...niether did Tim Dey at over 500....

You say you break automatics.....I gotta think they were VERY weak to begin with...since a properly running unit will hold more torque for far longer than the 5 speed.....

Originally Posted by 9x8

I'm not sure that static "it fits" measurement will be enough.

Originally Posted by BC

You mean to say that if I install and clamp the heads down properly and rotate the engine in time with clay on the piston that it won't be accurate? Are you concerned over heat expansion? I can verify this way that there is over a mm of space and that should be enough, no?

Originally Posted by 9x8

I'm not an expert on the subject, but I've also considered building a franken-motor, so I did think some about proper piston-valve clearance.
Aside from heat expansion, off the top of my head - there's also a problem with carbon buildup, and possible valve float at high rpm. Also, future variations in cam timing might also add up.

I have no idea what clearance is enough, but a quick google search suggested these values:
.11 inches for intake
.13 for exhaust

Which both translate to ~3mm.
Experienced engine builders might suggest other values though, so this is just some thought material.