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Old 05-05-12, 08:01 PM   #1
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My lead timing is logged at 3* at 23psi is this reasonable for my setup

This is for 93 pump gas and 500cc preturbo water injection. I am running a GT4094R with 106a/r hotside. Just wanted to know what you all think about my final timing for that boost level. This timing is at 6000 rpm, but it advances to about 7* by 8000rpm.

Please let me know if this is ok.
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Old 05-06-12, 12:30 AM   #2
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I'm kind of curious about your exhaust temps at that timing, with the water counter-acting it.
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Old 05-06-12, 07:02 AM   #3
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Quote:
Originally Posted by arghx View Post
I'm kind of curious about your exhaust temps at that timing, with the water counter-acting it.
I saw it as high as 1800F. Too high huh?
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Old 05-06-12, 07:59 AM   #4
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Needs more timing! What kind of ecu do you have?
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Old 05-06-12, 08:31 AM   #5
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Originally Posted by jetlude View Post
I saw it as high as 1800F. Too high huh?
Before the turbo right? That's almost 1000C. I'd say that's right at the limit where you could start degrading the turbo and, manifold, etc. I am assuming you've got a divided turbo manifold so that is going to keep most/all of the exhaust gases from flowing back into the engine. It's not like you're worried about cat life so that's not an issue.

I'd say if you left it alone now it should be plenty safe as long as your water injection doesn't fail. You would really have to see what happens when you advance the timing say 2 or 3 degrees at the highest boost levels. Pre turbo injection can help extend the knock limit, but there's only so much experimentation you can do with basic road tuning or chassis dyno tuning. How much do you want to risk knocking just to see what happens?

If it were me in your shoes, I would leave it as-is.
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Old 05-06-12, 12:01 PM   #6
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Quote:
Originally Posted by arghx View Post
Before the turbo right? That's almost 1000C. I'd say that's right at the limit where you could start degrading the turbo and, manifold, etc. I am assuming you've got a divided turbo manifold so that is going to keep most/all of the exhaust gases from flowing back into the engine. It's not like you're worried about cat life so that's not an issue.

I'd say if you left it alone now it should be plenty safe as long as your water injection doesn't fail. You would really have to see what happens when you advance the timing say 2 or 3 degrees at the highest boost levels. Pre turbo injection can help extend the knock limit, but there's only so much experimentation you can do with basic road tuning or chassis dyno tuning. How much do you want to risk knocking just to see what happens?

If it were me in your shoes, I would leave it as-is.
I really was not planning to advance the timing unless you guys advised me to in order to lower the egts.

I addition to that, I did find out that my vr sensors at the crank are further retarding the timing on their own. So that logged 3* at 23psi is actually even less in reality. I found it to be retarding the timing about 1* per 1000 rpm. That being said, I think another 2* should be ok. I would only do this advance to protect my turbo and other exhaust components, but if they could withstand 1800F I will leave it alone.
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Old 05-06-12, 07:06 PM   #7
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Maybe you should focus on getting your timing drift issues worked out and leave the map alone for now.
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Old 05-06-12, 08:50 PM   #8
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whats your split timing?
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Old 05-06-12, 08:56 PM   #9
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Quote:
Originally Posted by smg944 View Post
whats your split timing?
split= 12*
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Old 05-06-12, 09:32 PM   #10
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Timing too retarded and EGTs go up because your lighting the mixure too late and it's still burning in the exhaust.
1800*? way to high!! you could try lowering the boost to around 15-18, and advance the timing up and probably still hit 450+rwhp.
what was your timing on the 422rwhp 18 psi pull?
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Old 05-06-12, 09:52 PM   #11
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I don't know if 1800F is too high. It depends what the components can hold up to, and nobody can seem to agree on a number for that--especially since turbos and manifolds are vary.

There are lots of modern boosted piston engines running exhaust temps that hot off the showroom floor. They're mostly more expensive engines (think high-end German cars) with expensive turbos and manifolds.
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Old 05-07-12, 07:28 AM   #12
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I would consider using water/meth for that boost.

If you study Report No. 815 under NACA papers. The tests show the limits of the
different injected coolants on CFR test engine.

Both Indicated Mean Effective Pressure (IMEP) and Boost limits are listed.
Note-These tests were done by increasing pressure till knock was detected
and then backing off power 7% (so somewhat conservative).


Knock limit for rich fuel- IMEP 285 lb/sq in. (about 14 psi)
...................For water IMEP 325 lb/sq in. (about 18 psi)
..........For water/meth- IMEP 460 lb/sq in. (about 30 psi)

My tests so far show that the Rotary behaves similarly.

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Old 05-07-12, 07:35 AM   #13
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Quote:
Originally Posted by rxspeed7 View Post
Needs more timing! What kind of ecu do you have?
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Old 05-07-12, 07:56 AM   #14
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Quote:
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Maybe you should focus on getting your timing drift issues worked out and leave the map alone for now.
t

I actually did dome work on the drift last year I was able to dial it out. I have that map saved but I it not presently enabled. . The drift corrections were made while free reving the car and using the timing light. I am a bit afraid to enable it running this high boost since I am not sure if the drift pattern changes under load.

See my thread Timing drifting with RPM

The adjustments made to dial out the drift were significant, up to about 9* by 9000 rpm
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Old 05-07-12, 09:20 PM   #15
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When i build a map i start my timing 15* @ 15psi. So at 23psi id be at 7* for a start. Id bump it up to 7* and see how she is there and be sure to let us know the results.
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Old 05-29-12, 02:41 AM   #16
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Dont focus on the EGT so much.

Put another 2 degrees of timing into it and you should be very close to being on the money for power.

My rx7 on pump fuel had no issues with 1900F + as long as their no knock.
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Old 05-29-12, 02:41 AM
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