Huge congrats to the NY crew. You guys are busting out some amazing stuff. I might have to take a trip south one of these days and experience the miracles hands-on.

 

this question was asked by fritts "So what are the details of the setup ignition and fuel? Also how far were you able to push the timing and afr with E85?" my question i will add is what were the egt's.top secret or will you explain.i am a VW air cooled fan also,in the VW community there are no secrets.if you have a question about someones set up about 99.9% of the community will tell you exactly what there running.what is up with the rotary community?in case you would like to know about my car,my rx2 has a third gen engine,ford C4 trans,haltech E8 all the good stuff.it is on E85.best drinking buddy ever.

 

There's no secrets.
The car runs an Autronic SM2 and 500R with 4 Msd blaster coils..

I'm not one to push timing/fuel with street cars.. So i didn't push it on this car..

This car was tuned for MBT on the dyno and a/f was kept between 11~11.5

I don't have egts on this car yet i'll add them later on...

 

What is MBT?
Manipulating Best Timing!

Or
Mind Blowing Timing!

 

Mazda Beats Toyota?

 

Because of.....

Mostly Broken Trannies!

 

There appears to be two commonly used defintions for the term MBT. It may be a regional thing but I've seen two usages that are similar but have slightly different meanings that in some cases are important.

MBT Maximum Brake Torque would just be the highest torque your engine can achieve at a given engine rpm. YOu would get this info by putting the car on a dyno and tuning to find the ideal mixture, timing settings to give you the highest possible torque at the rpm of interest.


You will also see MBT used to mean Minimum Best Torque timing.
This deals specifically with ignition timing and how it effects engine torque. If you look at a graph of engine torque and how it changes at a single rpm as you modify ignition advance you will see it rises very quickly at first as you move toward the timing value that gives you Maximum Brake Torque.

You will also notice that as you get very close to that value the torque levels off and the engine torque output does not change much over a range of several degrees of ignition advance. What engineers discovered is that if you dial in the ignition advance that gave the absolute max torque and then pulled back the ignition advance so max torque dropped by only 1% you gave up a very small amount of torque but gained a huge advantage in the safety of the tune, and greatly reduced cylinder pressures and temperatures. This is the Minimum Best Torque timing. It is a very reliable and safe way to tune the engine.

Put the car on the dyno, keep adding advance until you get very little gain for each additional degree of advance, then back off a couple degrees until you just detect a small drop in max torque. This setting will give you some wiggle room for those situations where you peak the tune on the dyno but when you get on the road the car detonates like mad because it is hotter or the loading on the road is much different thant what the engine saw on the dyno.

I always use the term MBT timing to make it clear I am talking about ideal ignition advance.

In practical terms the two usages are essentially the same except with regard to the safety of the tune. If you tune the same engine to Minimum Best Torque, timing you will only be down by about 1% on the best Maximum Brake Torque. you could make if you pushed the engine right to the edge.

http://www.aquamist.co.uk/phpBB2/viewtopic.php?t=669

 

Some people have no sence of humor and thier knowledge of MBT is based on what they have read or quoted from unreliable sorces when it's applied to a rotary application. They need to stick to their night job

BTW. Anthony how do you find MBT on a Dynojet dyno?
I know Enzo is going to get a kick out of that one!

 

Anthony/Enzo put the dyno sheet up if ya get a chance.

 

congratulations on a huge accomplishment... there's nothing like alcohol.

since the title of the thread shows hp to the tenth i have to ask the question:

is it SAE or is it Standard?

howard coleman

 

It's corrected. I can look up the corrections but i believe that day was .957 or so.

 

Nice!
Curious to see how the powerband with that turbo on a stock motor look like.
I'll bet it's no different to some of those so called 'SP' and 'BP' motor's powerband.

 

i'll see tomorrow and post it...

If i remember correctly it hits around 5k. Power is there all the way upto 9000 rpms.
I didn't pull it to 9k with big boost since i know those are limited and will save them for a rainy day

 

I had no idea what MBT meant so I googled it, I'm sure I'm not the only one that did not know so I posted the info from the link to help the other non tuners like myself

 

You know I was messing with you!
Anyway you can always blame Aaron!

 

well, i must say that i NEVER expected this. it's a pleasant surprise and you deserve congratulations.

 

thats one amazing car keep up the work and hopefully we see some amazing times from that beast.

 

Amazing Amazing, nice one TurboR1 and Enzo!!!!
Im liking the fact the stock tranny is holding on to this power abuse lol !!
E85 is not readly available here yet in the UK at the pumps, I will be switching when it does no need for expensive race fuel anymore!

 

So you are saying porting has no effect on spool up of larger turbos?

 

******* awesome

 

That's an amazing amount of HP.

 

I''m saying that ENZO and crew are going about it the correct way. They know what a stock port can do so now with some porting they can see the differences may it be for the better or worse and from there make changes for the better.
Most of the BP and SP dynos I see on here are worse than stock ports.
I have done them all and know what works for me.

 

I've tested stock vs sp with this car when it had a GT35R.
We gained roughly 25~30hp and better top end..

my next combo should have some nice results...

 

Damn you, what works the best for you Always giving clues and never straight answers as we sit here and wait patiently

 

Howard is there a change from your earlier calculations on cc/hp that you have not included here?
Barry

[quote]
don't think so... not disputing your hp necessarily but definitely don't buy 4 1600 injectors w E85.

here's how i see it.

it takes 1.92 CFM to make one rotary rear wheel hp.

699 times 1.92 is 1342 CFM.

1342 CFM/14.471 is 92.72 lbs per minute of air.

let's say you did it at an AFR of 11.

92.72 pounds of air/ 11 is 8.43 pounds of gasoline.

but you didn't do it on gas... you did it on ethanol (i know E85 is 85/15... just hang with me.)

the equivalent Lamda to 11 gas is 4.8! if you were running 100% ethanol you would burn 19.32 pounds of ethanol per minute to make the same 11 AFR.

(alcohol has 9500 BTUs V gasoline at 18,400 BTUs per pound. the two quantities generate approx 184,000 BTUs)

converting from pounds per minute to CC/Minute:

to make 699 rw rotary hp on gasoline requires 5188 CC/Min

to make 699 rw rotary hp on (100%) ethanol requires 11,097 CC/Min

to do it on E85 takes 10,210 CC/Min

you have 4 1650 CC Min injectors.... that's 6600 CC/Min

that works out to 500 hp max at 100% duty cycle.

the car has either a whole lot of additional injectors or there's a typo on the hp.

FWIW i have a friend that makes 1000 rw rotary hp on 100% methanol and he has 14 1650 CC injectors.

'nothing personal here but it doesn't add up and will be interesting to hear the rest of the story.

one afterthought... injector flow rates are at a given pressure.. raise the pressure and you will get more flow. however, the increase in flow is the square root of the % change. in other words, if you moved pressure from 40 to 50, that would be a 25% increase in pressure but only a 5% increase in flow.



howard coleman

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Last edited by howard coleman; 02-24-09 at 08:32 PM.