Chris and Viking or anyone else,

Any opinion/suggestions regarding what I posted a few reply's above about what I plan to do with the timing?

I am kind of weary about timing changes but someone told be that I was being way too conservative for E85.

Thanks.

 

Honestly I ahve zero experience with E85, but have tuned a few setups....I wouldn't necessairly jump 4 degrees and then go at it....2 at a time until optimized IMHO.

 

one of a number of ways to zero in on timing is to digitally log preturbo egts. if you aren't running enough timing you will probably be too cold.

hc

 

actually if you don't have enough timing your egt's will be hot not cold....

 

Agreed!
Not to mention too rich afr's and retarded timing turns the exhaust in to a blow tourch and everything else just goes down hill after that.
High overlap & exhaust backpressure combined with the above and you light off the intake mixture way to early(preignition).

 

That holdes true with all types of fuel right? at least thats what ive understood and used when tuning my ignition maps. i

advanced it enough to cool it down, but not so far to the point of deminishing returns, or when i got nervous (which usualy came first)

 

I decided to take the car(RX-8 Renesis) back on the dyno one last time on gas before I completely submit to E-85 permanently.

Our goals where met! We got 414.xx whp on gas .

It was pig rich on the top end and I didn't attempt to tune that out since I was happy and though that was a high as I wanted to try to get to on gas.

Now I will completely tune the car out in E-85 and go again with a bigger turbo this time around

Thanks for all who gave tips.

Chris

 

Are you modifying the renesis engine to get that power? and how rich was it running up top? 9-10's? I'v not heard much of anyone playing with renesis motors so it would be nice to see a dyno..hope its not much trouble

 

That number was on a regular renesis. I have been working on a dowel-pinned one with apex seals that is going in the car as we speak with a PT71GTQ turbo instead of the T04S. I just had to test it with what the kit actually brings first and on a stock motor to show potential customers what it is capable of. We ran in the mid 10's AFR dipping into the 9's past 7000rpm.

Chris

 

Congrats Chris!
Lean it out a little on the top and the power will shine where the renesis love it the most.
The 71GTQ is a very nice turbo!
You will have to run some real boost to see the benefits though.

 

I am impressed! What kind of seals are going into it?

 

The seals are actually made by us. They have been in a stock car for about 6 months undergoing testing before getting into this engine. I just test drove the car with the PT71gtq, holy crap, it feels good. I am wandering where I should be AFR and timing wise in the ramp up part of boost to reduce lag as much as possible.

Any suggestions?

Thanks,
Chris

 

I don't have a turbo rx8 to play with but my personal best comes from 10.1 or 10.2.
My setup is irrelevant to your project but keep us updated as its really interesting. There are a few guys I know who have tuned turbo rx8's (never saw 400whp just about 340max@7900 rpm and 9.8afr) and I'll ask around for data. Till then best of luck on a very exciting project!

 

Ill throw in my 2cents since I had tuned my s13 on e85.
The timing needs to be advanced, the burn rate on e85 is around 27% (give or take) slower than pump gas. Also, it nets less power per cm2 so you will need more fuel. It does burn colder however, and I personally noticed my car running about 4 degrees cooler. The spool rate doesnt change much, as the exhaust is colder which would slow spool, but the volume is greater which would increase spool. They cancel each other out. Power gains are very obvious, on the same boost, but e85 allows you to run more boost... alot more.
Just for example (do not tune based off of what i write, please, your combustion properties will be completely different than mine)
I increased fuel between 35 - 60 percent over my 91 tune, ran two more psi (just because for my purposes, any more power would be un-usable), and had timing stepped foreward 5-9 degrees over the map. Now keep in mind that the fuel increase was also due partially to more boost, and on a fairly straight foreward tune most people go about 40 percent. I never dynoed my car ( was actually planning on it, but it got stolen), but my freinds sr, on 18 psi with a 2871r put down 284 wheel.
Hope this helps!