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-   -   Just can't break the 200hp mark! (https://www.miataturbo.net/engine-performance-56/just-cant-break-200hp-mark-52717/)

Joe Perez 10-17-2010 10:33 PM


Originally Posted by pdexta (Post 644517)
If I remember correctly it was determined that, despite what the gauge tells you, the wideband is not really reading an AFR but is instead reading a stoichiometric mixture ratio.

This is correct.

The sensor itself reads lambda, and then the controller / gauge contains either a lookup table or a formula which translates this to an AFR. Assuming that the gauge is calibrated for gasoline, a labmda reading of 1 will produce a display of 14.7, regardless of what fuel you're burning. So if you're burning E85 and yet your gauge is calibrated for gasoline, a displayed value of 14.7 actually means a true AFR of 9.765.

Download a copy of the AEM UEGO manual. It contains a table which correlates various AFR / lambda readings of various fuels.

Savington 10-17-2010 11:26 PM


Originally Posted by Rushin (Post 644497)
So for the past two years i have been trying to break 200hp mark. And just cant do it. My setup: Begi cast iron mani, gt2554, mspnp, custom 3" dp and exhaust. small ebay intercooler( feeling like thats the issue). Step colder plugs. 600cc injectors, walbro pump, manual boost controller.

The car is tuned by me on e85 at about 12psi peak boost. Timing is set at about 20 degrees at peak boost. And afrs are at 11.5 and taper down to 10.5 at peak boost (feel like quite a bit too rich for e85). At peak boost my MAT was at 98 degrees, which i dont think is that hot, right?

Yesterday i did 193hp and 180 torque. I was really hoping to break the 200hp mark.

Setup is all there, that's basically the same setup I made 217whp through. Lean the AFRs out - low 12s are safe on E85. 20 degrees is more than enough, I was running like 14-15deg at 16psi on pump gas. Leakdown/compression numbers? 1.6 isn't helping, I made those numbers on a stock '99 longblock.


Originally Posted by Aricjm15 (Post 644514)
Copied from wikipedia

E85 stoichiometric 9.765
E85 max power rich 6.975
E85 max power lean 8.4687

http://en.wikipedia.org/wiki/E85_in_...tio_comparison


Internet armchair wisdom is failing you. Widebands read lambda and convert to air/fuel ratio. 14.7:1 on gasoline is 1.0 lambda, and it's still 1.0 lambda if you switch to E85, and the gauge will still read 14.7:1 even though the stoich ratio is 9.7. As E85 has become more prevalent, most folks have left their widebands set up for gasoline and just referred to the AFRs in that manner. Thus, when he says 11.9:1 AFR, I have no idea what AFR he actually is at, but I know that he's safe or perhaps a hair rich on E85.

edit: beaten by like 4 people.

Rushin 10-17-2010 11:49 PM


Originally Posted by Savington (Post 644653)
Setup is all there, that's basically the same setup I made 217whp through. Lean the AFRs out - low 12s are safe on E85. 20 degrees is more than enough, I was running like 14-15deg at 16psi on pump gas. Leakdown/compression numbers? 1.6 isn't helping, I made those numbers on a stock '99 longblock.

Head is stock but pretty much brand new. 3 angle valve job has been done last year.

bottom end has around 145k on it. 3cyl has lower compression than the others.

rider384 10-18-2010 12:27 AM


Originally Posted by Rushin (Post 644659)
bottom end has around 160k on it. 3cyl has lower compression than the others.

Fixed that for ya ;)

Braineack 10-18-2010 08:37 AM

why are we running e85 for 200rwhp again?

I was hitting 200rwhp at 13psi on my old T3 setup, with a 2.25" exhaust and the stock ECU.

your fuel map looks whack, why so rich between 3000-4000RPM in cruise?

Rushin 10-18-2010 08:50 AM

At what map is it rich? Its probably my cruising. Car run too hot and too lean when cruising.

Braineack 10-18-2010 08:57 AM

You go from 57% VE to 91% VE in cruise cells. That a LOT more fuel at just 75kPa. Honesty the table as a whole just looks completely untuned.

Why are your AITs so high? and Why aren't you using the AIT corrections table to compensate, NOT the VE table.

Rushin 10-18-2010 08:59 AM

Never played with ait table. What does it do?

Not sure, why it runs hot. Pribably because the air is not hitting the intercooler ad the radiator. I am missing the air guide and the under body plastic guard.

I am sometimes seeing 1400-1500 degree egts when cruising.

Braineack 10-18-2010 09:03 AM

I can't help you. I don't understand the reason for the e85, nor do I have knowledge of how to run with it. Sounds like you have an underlying issue, I see no reason your AITs would get high in cruise, unless your intake was behind the radiator or something.

EGTs mean nothing to me, could be too little or too much timing and other various non-absolutes.

are you sure your cat isn't clogged or something?

Rushin 10-18-2010 09:04 AM

I by no means a professional tuner, so don't be to harsh. I have not touched anything except ve map and spark map a little bit.

miataspeed2005 10-18-2010 09:06 AM

I made 233whp on a greddy (12-13psi) with a 2.5 exhaust and pump gas. There's no reason why you should be running e85 on a car that doesn't even make 200whp.

Rushin 10-18-2010 09:08 AM


Originally Posted by Braineack (Post 644775)
I can't help you. I don't understand the reason for the e85, nor do I have knowledge of how to run with it. Sounds like you have an underlying issue, I see no reason your AITs would get high in cruise, unless your intake was behind the radiator or something.

EGTs mean nothing to me, could be too little or too much timing and other various non-absolutes.

are you sure your cat isn't clogged or something?


Well e85 has a way higher octane rating, that fr starters. Pretty much proven to make more power if tuned well. Its safer because it does not detonate as early as pump 91-93 does. And it does not smell, biggest issueni had is because I am catless every time I come to a stop sign I wanted to throw up.

My ait are fine. The egts were high at cruise and afrs would climb to high 16s so I dropped them down to high 14s low 15s. And took the timing out in the cruise area.

Rushin 10-18-2010 09:10 AM


Originally Posted by miataspeed2005 (Post 644777)
I made 233whp on a greddy (12-13psi) with a 2.5 exhaust and pump gas. There's no reason why you should be running e85 on a car that doesn't even make 200whp.

When I switch to e85 it was night and day. Car runs so much smoother and does not have smoking issue anymore. Maybe coinsidense but it's a fact in my case.

Braineack 10-18-2010 09:21 AM

can you post your msq and log file please?

Rushin 10-18-2010 09:22 AM

Sure. Anything that will help me understand why I am not making more power.

Rushin 10-18-2010 09:30 AM

2 Attachment(s)
Here is the msq and the dyno log.

rider384 10-18-2010 10:39 PM


Originally Posted by Rushin (Post 644778)
Well e85 has a way higher octane rating, that fr starters. Pretty much proven to make more power if tuned well. Its safer because it does not detonate as early as pump 91-93 does. And it does not smell, biggest issueni had is because I am catless every time I come to a stop sign I wanted to throw up.

My ait are fine. The egts were high at cruise and afrs would climb to high 16s so I dropped them down to high 14s low 15s. And took the timing out in the cruise area.

Retarded cruise timing could be causing the EGTs. Same with the rich fuel around cruise. Think about it - the more you retard the timing, the later it will spark, meaning that the gasses will be hotter going through the exhaust. Same thing with more fuel. The more fuel it burns, combined with the fact that it's burning later means that the gas will be hotter than a leaner, more advanced map.

Rushin 10-18-2010 10:42 PM


Originally Posted by rider384 (Post 645189)
Retarded cruise timing could be causing the IATs. Same with the rich fuel around cruise. Think about it - the more you retard the timing, the later it will spark, meaning that the gasses will be hotter going through the exhaust. Same thing with more fuel. The more fuel it burns, combined with the fact that it's burning later means that the gas will be hotter than a leaner, more advanced map.

You got it wrong. More timing causes the car to run hotter. Less fuel causes leaner mixture making the car run hotter.

And there is little AIT connection between fuel mixture and timing. AIT is way before anything gets burnt.

High AIT in my case is either cause by a tiny intercooler or not enough air hitting it.

rider384 10-18-2010 10:45 PM


Originally Posted by Rushin (Post 645191)
You got it wrong. More timing causes the car to run hotter. Less fuel causes leaner mixture making the car run hotter.

And there is little AIT connection between fuel mixture and timing. AIT is way before anything gets burnt.

High AIT in my case is either cause by a tiny intercooler or not enough air hitting it.

I meant EGTs. My bad. Get a bigger IC :).

Rushin 10-18-2010 10:50 PM

The reason why i took out timing at cruise and richen that area is because i was running close to 1500 degrees egt and the CLT would get close to 210 degrees.


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