Miata Turbo Forum - Boost cars, acquire cats.
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Miata Turbo Forum - Boost cars, acquire cats. (https://www.miataturbo.net/)
-   Engine Performance (https://www.miataturbo.net/engine-performance-56/)
-   -   high compression e85 turbo bp? (https://www.miataturbo.net/engine-performance-56/high-compression-e85-turbo-bp-72064/)

thenuge26 Apr 17, 2013 06:19 PM
lol while you were away there was a lot of shitposting, but we also found the answer you are looking for.

Might be 10.5:1, might be 11:1, It's not yet known. If you can reach MBT at 11:1, that will be better. If you can't, 10.5:1 will probably be better.

Savington Apr 17, 2013 06:42 PM
Originally Posted by thenuge26 (Post 1002487)
If you can reach MBT at 11:1, that will be better. If you can't, 10.5:1 will probably be better.
dingdingding. The only empirical evidence I have is of one guy (eliminator77) who said that he did 9.5:1 and regretted not going higher. That's where I'm basing my 10.5:1 starting point for my E85 shortblock on.

hustler Apr 17, 2013 09:27 PM
Tork is functionally retarded.

18psi Apr 17, 2013 10:53 PM
1 Attachment(s)
https://www.miataturbo.net/attachmen...ine=1366253584

TNTUBA Apr 19, 2013 07:12 AM
1 Attachment(s)
Originally Posted by thenuge26 (Post 1002400)
Ok, in a futile attempt to save this trainwreck, I have a question.

MBT (maximum brake torque) is achieved when maximum cylinder pressure is reached at a certain point (about 15° ATDC). It is the most power you can make at a given compression.

There is mountains of data that shows a BP@8.6:1 will reach MBT on pump gas, and make more power than the same engine would at 9:1 because the 9:1 cannot reach MBT on pump gas.

Does anyone have any data on the highest compression that can be used while still reaching MBT on E85? 10.5:1 is good, but if you can reach MBT on 11:1 it will be better. Anyone found MBT@11:1 running E85?
This post was not edited for spelling or grammar

Not the highest no. But with a milled head/block and Weisco "advertised 10.5:1" pistons resulting in a calculated static CR of 10.87:1; I was able to reach MBT running 17PSI boost from a Positive displacement supercharger and C-16 fuel.

I can tell you that with pump gas this thing would prob make less power than a JRSC'ed Miata with a RRFPR due to limited timing.

It amazes me that some people have such a hard time understanding the simplest of concepts. Timing makes MORE power than Compression (or boost) when you are limited by the detonation threshold of a particular fuel. If you are no longer living within the limits of that fuel you can make more power by increasing compression(and or boost) and timing.

Obvious troll it obvious. Stop feeding them

Here's the spark map
https://www.miataturbo.net/attachmen...ine=1366369933

muoto Apr 22, 2013 08:42 AM
Holy shit how much timing you have :eek5:

With my 9.5:1 pistons I didn’t get any torque gains after 20-22deg. Here’s my E85 spark map


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