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![]() Enthusiast ![]() Joined Dec 9, '05 From Germany Currently Offline Reputation: 0 (0%) ![]() |
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Jun 18, '09 From Orlando Currently Offline Reputation: 8 (100%) ![]() |
Interesting. OOBE said that 8 PSI was the max on stock internals. No issues whatsoever though?
-------------------- '97 ST \ Eibach \ KYB \ Kenwood \ Alpine \ Cusco \ OEM+ [sold 10/18]
'93 MX-5 LE |
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![]() Enthusiast ![]() Joined Dec 9, '05 From Germany Currently Offline Reputation: 0 (0%) ![]() |
No issues at all, it depends on the injection and especially the ignition tuning how much a 7A will handle without braking something. I tuned my 7A to run with an afr of 11,5:1 at full boost and retarded the timing a lot. It's absolutely important to watch engine knock while tuning.
8 psi is pretty safe on a good tuned 7A, 10 psi is the max i would give a stock engine over a longer period of time, maybe 12-13 psi with an water injection. If you want to go higher you have to lower the compression and get some stronger internals... |
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Aug 30, '02 From San Juan, PR Currently Offline Reputation: 4 (100%) ![]() |
Interesting. OOBE said that 8 PSI was the max on stock internals. No issues whatsoever though? WTF? I NEVER said that 8 PSI was the max on stock internals. I've had mine to 15 PSI. ![]() The "mechanical engineer" guy was the one that said that. I was the one that broke that myth here years ago about the 7A-FE not being able to handle more than 7 PSI. -------------------- |
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Jun 18, '09 From Orlando Currently Offline Reputation: 8 (100%) ![]() |
No issues at all, it depends on the injection and especially the ignition tuning how much a 7A will handle without braking something. I tuned my 7A to run with an afr of 11,5:1 at full boost and retarded the timing a lot. It's absolutely important to watch engine knock while tuning. 8 psi is pretty safe on a good tuned 7A, 10 psi is the max i would give a stock engine over a longer period of time, maybe 12-13 psi with an water injection. If you want to go higher you have to lower the compression and get some stronger internals... I do know stronger internals are eventually necessary, I just thought that point was past 8 PSI. WTF? I NEVER said that 8 PSI was the max on stock internals. I've had mine to 15 PSI. ![]() The "mechanical engineer" guy was the one that said that. I was the one that broke that myth here years ago about the 7A-FE not being able to handle more than 7 PSI. OOBE, you lied to me! ![]() So both of you guys, push the hell out of your engines so Ferdi has plenty of study material! This post has been edited by SwissFerdi: Nov 9, 2009 - 5:11 PM -------------------- '97 ST \ Eibach \ KYB \ Kenwood \ Alpine \ Cusco \ OEM+ [sold 10/18]
'93 MX-5 LE |
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Aug 16, '03 From Bay area Currently Offline Reputation: 0 (0%) ![]() |
After about 7k miles the engine still runs great, i did a compression test some weeks ago with ~190psi on all cylinders. The 7A really can take some abuse.. over 200 miles or 15 turns at the circuit without any problems, even at over 90°F ambient temperature. The engine gets 10psi boost at all day driving and 7-9psi at the track, depending on the weather thanks to boost creep at low temps.... Oil consumption is a little bit high with almost 1L/1000km... but it could be worse ![]() The fuel consumption is not bad with ~27 mpg overall and 20 mpg at the circuit. I got a short video from the Autobahn, testing 100-200 km/h acceleration at 10psi Youtube awesome look at that odometer move! |
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Aug 30, '02 From San Juan, PR Currently Offline Reputation: 4 (100%) ![]() |
Ferdi,
With good tuning, 10 PSI on a good size turbo is nothing for this engine. You can run it daily. Even with the piston I hurt in the dyno, I was still boosting 15 PSI daily until the car overheated because of a failing radiator fan last week. The broken piston never got more hurt than what it was when I overboosted 18 PSI at the dyno, which is when it broke. The dyno read 222 WHP when the piston broke and I wasn't even on WOT. Who knows if the engine saw over 250 horses. The dyno read that, but the engine might've made way more. ![]() Remember that different turbos give you different power per pound of boost, and the weather conditions affect power A LOT, which is a very important fact that most people forget or fail to realize. In my case, just one PSI in the lower boost range on my turbo counts for ten wheel horsepower according to the dyno, and that's on 85 degree weather at night with a lot of humidity. I might get more on a cool day, which never happens in this island. I also have a bigger turbo, custom intake manifold and bigger throttle body...and also a more efficient intercooler with a horrible two PSI pressure drop. These items were not installed last time I dynoed, so I cannot compare the numbers. Everything changed. Who knows how much these items helped the engine or took away. I couldn't baseline unfortunately. At 15 PSI, I'm probably getting a bit more than ten wheel horsepower per pound of boost, since the turbo is in its sweet spot on higher boost. Taking this into consideration and given the acceleration rate and how the car feels, if I follow that 10 WHP/PSI ratio, who knows if I'm probably at 250 WHP as of now...ignoring that the head is warped and that the piston is hurt. ![]() ![]() If it wouldn't have overboosted, it wouldn't have broke a piston and I ASSUME I would be around that power level, give or take. A smaller turbo will give you less obviously. So after my experience, I can say that with a good tune, you can boost a bitty more than 200 WHP daily with no problems. ![]() This post has been edited by OOBE: Nov 9, 2009 - 6:15 PM -------------------- |
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Jun 18, '09 From Orlando Currently Offline Reputation: 8 (100%) ![]() |
With good tuning, 10 PSI on a good size turbo is nothing for this engine. You can run it daily. Even with the piston I hurt in the dyno, I was still boosting 15 PSI daily until the car overheated because of a failing radiator fan last week. The broken piston never got more hurt than what it was when I overboosted 18 PSI at the dyno, which is when it broke...about 230 WHP...which yields about 250 or more to the engine sicne this is an auto tranny. That's asking a lot. These are replacement pistons, so they might be weaker than Toyota pistons. Remember that different turbos give you different power per pound of boost, and the weather condiions affect power A LOT...something that most people forget or fail to realize. In my case, just one PSI on my turbo counts for ten wheel horsepower, and that's on 85 degree weather at night with a lot of humidity. I might get more on a cool day. A smaller turbo will give you less power per pound of boost. So after my experience, I can say that with a good tune, you can boost a bitty more than 200 WHP daily with no problems. That's great to hear. 200 WHP would be PLENTY for me, especially coming from...80ish WHP? ![]() This post has been edited by SwissFerdi: Nov 9, 2009 - 6:01 PM -------------------- '97 ST \ Eibach \ KYB \ Kenwood \ Alpine \ Cusco \ OEM+ [sold 10/18]
'93 MX-5 LE |
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Aug 30, '02 From San Juan, PR Currently Offline Reputation: 4 (100%) ![]() |
Well, the most important thing is to find a good tuner, and either use an e-Manage, or an AEM FIC, or better yet, a stand-alone EMS, because you NEED to be able to control timing if you want the engine to last. I've broken a piston three times in six years. The first two times were because of detonation, not boost level or leaning out. This engine advances timing a boatload when accelerating. You will not believe it. I wish I would've recorded when my tuner took timing readings with a very expensive digital timing light. It was unreal and we were surprised that the engine lasted through all that abuse with such advanced timing throughout these years. By the way, I just sold my e-Manage last week. It worked awesome, but I need more control of the engine because I'm aiming for good numbers now since I'm going with forged internals.
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Jun 18, '09 From Orlando Currently Offline Reputation: 8 (100%) ![]() |
I'd love to find somebody local that knew their way around a 7A-FE, or at least a turbo'd version of a Japanese 4-banger...my mechanic might have a hookup though, or know himself actually. I imagine those systems are pretty expensive? Well worth it though, obviously.
So basically, if the timing's off, the spark won't go off relative to the correct piston position and it'll just run like crap? This post has been edited by SwissFerdi: Nov 9, 2009 - 8:09 PM -------------------- '97 ST \ Eibach \ KYB \ Kenwood \ Alpine \ Cusco \ OEM+ [sold 10/18]
'93 MX-5 LE |
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Aug 30, '02 From San Juan, PR Currently Offline Reputation: 4 (100%) ![]() |
The spark will go off regardless, and there is no such thing as correct piston position. It depends on the engine and what you want to do with it. The point is that if the timing is too advanced, you'll get detonation. Detonation kills engines inside. There are different kinds of detonation. That's why you need high octane fuel or meth/water injection to run high boost. No need for someone to know about 7A-FE engines. My tuner is a 3S-GTE expert, but he has never touched a 7A-FE before mine. It's all about knowing the principles of tuning.
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Jun 18, '09 From Orlando Currently Offline Reputation: 8 (100%) ![]() |
Okay. I was just thinking in relation of the piston in the chamber moving toward the spark or away from it...if that makes sense.
This post has been edited by SwissFerdi: Nov 9, 2009 - 9:05 PM -------------------- '97 ST \ Eibach \ KYB \ Kenwood \ Alpine \ Cusco \ OEM+ [sold 10/18]
'93 MX-5 LE |
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![]() Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Feb 28, '07 Currently Offline Reputation: 1 (100%) ![]() |
Detonation would be the the spark igniting the mix b4 the piston is a TDC(top dead center)...thus teh crank forcing the piston up and the mix forcing it down(bad mix
![]() -------------------- BANNED. for life, you moron.
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![]() Enthusiast ![]() Joined Dec 9, '05 From Germany Currently Offline Reputation: 0 (0%) ![]() |
Detonation would be the the spark igniting the mix b4 the piston is a TDC(top dead center)...thus teh crank forcing the piston up and the mix forcing it down(bad mix ![]() The mixture is always ignited before TDC ![]() Pre-Ignition would be the really bad thing thats forcing the piston down when it want's to go up... |
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![]() Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Feb 28, '07 Currently Offline Reputation: 1 (100%) ![]() |
well i ment wayyy before haha...Detonation=heat...pre-ignition=timing
This post has been edited by CelicaST_CALI: Nov 10, 2009 - 11:40 PM -------------------- BANNED. for life, you moron.
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Jun 18, '09 From Orlando Currently Offline Reputation: 8 (100%) ![]() |
Hafkai, another question...you're running the stock transmission right? I'd like to do a manual swap before I turbo, and I'm wondering if the ST's C52 (?) will hold the power, or if I should just get the GT's S54.
-------------------- '97 ST \ Eibach \ KYB \ Kenwood \ Alpine \ Cusco \ OEM+ [sold 10/18]
'93 MX-5 LE |
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![]() Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Feb 28, '07 Currently Offline Reputation: 1 (100%) ![]() |
Ferdi,doc told me he had a 4agze with a c52 and 225 running through it fine..
-------------------- BANNED. for life, you moron.
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Enthusiast ![]() ![]() Joined Jan 17, '04 From Boston, MA Currently Offline Reputation: 1 (100%) ![]() |
> Nov 9, 2009 - 8:02 PM
> SwissFerdi > '97 ST Hatchback > From Fort Myers, FL > I'd love to find somebody local that knew their way around a 7A-FE, or at least a turbo'd version of a Japanese 4-banger... We'd All love to find a professional to do it. > So basically, if the timing's off, the spark won't go off relative to the correct piston position and it'll just run like crap? Learn to tune Yourself ? www.efi101.com How far away is Port Charlotte ? EFI-101 Fundamentals of High Performance Engine Tuning Using Aftermarket Electronic Fuel Injection Port Charlotte, FL (Relentless RPM) http://www.efi101.com/schedule.php?cat=EFI&country=USA Regards; |
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Enthusiast ![]() ![]() Joined Apr 22, '07 From Buckinghamshire, UK Currently Offline Reputation: 2 (100%) ![]() |
OOBE, i've only taken 1 degree per psi of boost. I'm running at 9 psi.
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Enthusiast ![]() ![]() ![]() ![]() ![]() Joined Jun 18, '09 From Orlando Currently Offline Reputation: 8 (100%) ![]() |
Learn to tune Yourself ? www.efi101.com How far away is Port Charlotte ? EFI-101 Fundamentals of High Performance Engine Tuning Using Aftermarket Electronic Fuel Injection Port Charlotte, FL (Relentless RPM) http://www.efi101.com/schedule.php?cat=EFI&country=USA Regards; Appreciate it, but $500 for two days of class? Holy crap! This post has been edited by SwissFerdi: Nov 11, 2009 - 4:06 PM -------------------- '97 ST \ Eibach \ KYB \ Kenwood \ Alpine \ Cusco \ OEM+ [sold 10/18]
'93 MX-5 LE |
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