Single Turbo RX-7's Questions about all aspects of single turbo setups.

352whp @ 14psi - low or normal for GT35R?

Old Sep 20, 2013 | 06:43 PM
  #126  
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Originally Posted by REsuper7
Well 6 months have passed since i originally posted this thread and i figured i'd post a quick status update in case people still thought my tune was crap. I've put about 5000 miles on the car since the tune and even had a chance to do a few laps at Pocono FUSA which is a FAST track considering the back straight is part of the NASCAR oval. I'm happy to report that the car still runs just as well as the day i got it tuned even after many redline/full boost pulls. No cold/hot starting issues. No lumpy idle or low speed jerkiness. Needless to say, i'm still very happy with the tune and glad i didn't bother with getting it retuned. Not to open up a can of worms or anything, but if a car can run this well with a "crappy tune", then perhaps "crappy tune" needs to be redefined.

I'll report back in another 6 months...hopefully it'll be a simple copy/paste of this post.
Nice! Glad to hear everything's been running well for you and that you were able to enjoy the driving season so far
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Old Sep 20, 2013 | 07:15 PM
  #127  
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Thanks for updating this mess of a thread OP.

I disagree with the comments that if a hiccup happens it doesn't matter if you're tuned 11:1 or 12:1. Obviously if your hiccup is a failed injector it probably won't matter much, or if someone pours sugar in your gas tank, those hiccups would result in the same damage regardless of AFR, but if you're tuned on the edge and you get a bad tank of gas, you're much safer tuned conservatively than on the edge. If you're running race fuel this is of little concern, but in a real world street car on pump gas things like this can and do happen.

Other things like overboost from a vacuum line coming loose, a piece of carbon glowing on the rotor surface, excessive intake temps, and many other things can be the difference between surviving the hiccup or not.

As far as power made, T3 housing, restrictive exhaust, stock ports, unknown other components. 350 sounds about right to me. I didn't look at the map or anything, but sounds like timing is base PFC timing, it's already on the lean side so I'm not sure how the tuner could get more power without putting the engine at even more risk.

11.7 afr @14 psi is a little on the lean side, but not really overly extreme. I would be happier around 11.3 and would probably set a definite limit of 11.5, but 11.7 is okay as long as you can always count on your fuel being of quality. I personally recommend a water injection kit for anyone running over 12 psi. With Aux injection i wouldn't be surprised if 12.5 was a safe tune (though I still wouldn't tune that lean) it would definitely make me feel better about 11.7 though.

As far as interpolation between the cells, having numbers going all over the place is just not professional, you might get your AFR's in line, but its just tacky and makes reading the map and tuning more difficult. Sloppy things like this just shouldn't come from a professional. It's like watching your fast food handler pick their nose and then hand you the food, maybe it doesn't change the flavor of your food, but its gross, unprofessional and makes you second guess everything else about the food.
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Old Sep 20, 2013 | 09:26 PM
  #128  
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Just a little FYI to anyone reading who has the default PFC leading and trailing timing maps: I've explained in another thread in the 3rd gen section that you can increase the safety margin of the timing by retarding your trailing (increasing split).

Originally Posted by arghx
The basemap trailing timing on the PFC model #414-Z004 , the model that most people have, is less safe once you get over about 10psi (and the timing progression is sloppy). But the safety aspect is correctable even with a Commander just by tediously going through the IGT screen, rows P16-P18 (8.5psi to 14 psi range), and retarding the timing (decrease the timing value) by about 4 degrees in every cell over say 2400 rpm (N7 and higher columns in the commander). So take whatever value is in a particular cell, subtract 4 from it, and then input that new value in the cell.

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Old Sep 26, 2013 | 01:42 AM
  #129  
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11.7@14psi is not really that lean.

I tune a lot of cars these day's and just recently saw a workshop tune a car which I retuned a few days later and car was running 12.5s at 18psi on pump fuel. Engine survived with no issues. I obviously did not leave it there, i usually tune as rich as possible without compromising ignition.
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Old Sep 26, 2013 | 09:25 AM
  #130  
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Originally Posted by rx72c
11.7@14psi is not really that lean.

I tune a lot of cars these day's and just recently saw a workshop tune a car which I retuned a few days later and car was running 12.5s at 18psi on pump fuel. Engine survived with no issues. I obviously did not leave it there, i usually tune as rich as possible without compromising ignition.
I've unintentional ran my car that lean on 15+ psi pulls, never popped and had a nice power band but it's safe to say a lean tune like that is on borrowed time right?
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Old Sep 26, 2013 | 11:03 AM
  #131  
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Originally Posted by rx72c
11.7@14psi is not really that lean.

I tune a lot of cars these day's and just recently saw a workshop tune a car which I retuned a few days later and car was running 12.5s at 18psi on pump fuel. Engine survived with no issues. I obviously did not leave it there, i usually tune as rich as possible without compromising ignition.
same here
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Old Dec 31, 2014 | 07:32 PM
  #132  
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Originally Posted by rx72c
11.7@14psi is not really that lean.

I tune a lot of cars these day's and just recently saw a workshop tune a car which I retuned a few days later and car was running 12.5s at 18psi on pump fuel. Engine survived with no issues. I obviously did not leave it there, i usually tune as rich as possible without compromising ignition.
Was the 12.5 and 18psi on a rotary? Sorry for bringing this back but I have a question. How could any of the above quoted examples be considered not too lean? I know every experienced tuner has their own feel good safe zone but what's really a TRUE safe zone? I'm not a tuner by any means as I've only self taught myself how to tune my NA 20b but to me, if you can't run 87 octane and run safely at that same psi and A/F then it shouldn't be considered safe. I mean is it possible for the truck driver to accidentally put 87 octaine in the 91 octane tank at the gas station?

When Mazda tuned the fd, I'm sure they took all that into account. Bone stock Fd recommended 91 octane but could still run safely with 87 (though not recommended). I drove mine around for a yr and a half with 87 in the tank without issues. Mazda couldn't put a product out in the market that couldnt run on all available fuels. I guess thats why they tuned so pig rich in the 1st place to make 87 safe. So are you tuners treating your tunes with the same respects?
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Old Jan 2, 2015 | 07:53 AM
  #133  
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^ When making power you tune based on the fuel you intend to run not what can possibly go in the tank.
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Old Jan 2, 2015 | 01:03 PM
  #134  
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^ That makes since but, is that saying it's not possible to make the same desired power on 87? I mean has anyone tried to reach the safe limits of 87 on a 13b?
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Old Jan 2, 2015 | 01:20 PM
  #135  
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^ What does desired power mean?

If by desired power you mean 200 hp then yes but if desired power is 400 then no
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Old Jan 2, 2015 | 05:45 PM
  #136  
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^ Yes I was meaning the customers desired hp level. Something well above stock levels.
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Old Jan 3, 2015 | 02:55 PM
  #137  
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Originally Posted by t-von
^ Yes I was meaning the customers desired hp level. Something well above stock levels.
I don't understand why you would go that route or waste the time? I'm sure getting a bad tank of gas can happen but I think that is a tuner excuse 99.9% of the time and not reality.

Assuming a cost difference of $.30 between 87 and 93 you would save a whopping $200.00 every 10,000 miles at 15mpg. The way we all drive our cars we would save about $40.00 bucks a year.
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Old Jan 3, 2015 | 08:50 PM
  #138  
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Yes it was a rotary.
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Old Jan 4, 2015 | 02:08 PM
  #139  
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Originally Posted by djseven

I don't understand why you would go that route or waste the time? I'm sure getting a bad tank of gas can happen but I think that is a tuner excuse 99.9% of the time and not reality.

Assuming a cost difference of $.30 between 87 and 93 you would save a whopping $200.00 every 10,000 miles at 15mpg. The way we all drive our cars we would save about $40.00 bucks a year.

The point is making it safe for all available fuel grades (just like stock) and not having to worry about ONLY putting in a specific fuel grade. It's not just about cost difference either as sometimes 93 may not be available. If a lower grade, is all thats available, then the driver is gonna be paranoid and take things easy until they find their grade. I've noticed more gas stations only carrying 87 recently. I just feel that we would have a lot less blown engines if more tunes took into account all the available fuel grades and not just whatever you tuned with in the 1st place.

I did my own experiement with my stock car for curiosity reasons and was paranoid in the beginning while doing it. I then realized that Mazda obviously took into account that the engine would need to run reliabily on 87 and I stopped worrying about. It's just added piece of mind that's all.


I just figure if more consideration was given to being able to run with lower grades, then we would probably have far less blown engines.
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Old Jan 4, 2015 | 06:44 PM
  #140  
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Manufacturers have to account for the lowest common denominator; i.e., the customer who doesn't realize or care what fuel goes in the tank. People using their own engine management and tune may not feel the need to do the same.
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