5sfte fuel

[mr2 guy]

*mods im not sure if I posted this thread in the right area, if its not please move it. I couldnt find the 5sfte area.

Alright guys my friend is thinking about doing the 5sfte setup on his 92. Yea I know its much better to go get a 3s dropped in there and thats probably what most of yall will say but just stay with me. We know the whole basic setup: ct-26, 2bar map sensor, most 3sgte turbo parts, 7mge(I beleive) lime-top supra injectors, MSD BTM. My question is would it be any better if not any better to just use the stock injectors with an FMU with like a 12:1 or 10:1 ratio?( thats what all the honda guys use in their integras and civics) Because when we use the supra i think 315cc's thats the only fuel component upgrade there is and nothing to be controlling them. Wouldnt that be running a bit richer than it has to, thus loosing power? Thanks in advance for the help.

[Weasy2k]

Well i would rather get the larger injectors and a proper piggyback to control it all.

The units i always use is the SMT6 which can also control timing which we all know is the leading cause of DEATH to the engines that go turbo from n/a
Of course you can use the unit to control your fuel levels as well.

[blackbob]

You could also get ahold of a SAFC II and that will allow you to control the injectors +/- 50%. It's an affordable way to control them until you're ready to go piggy back or standalone and is also used by the honda guys.

[Weasy2k]

the S-AFC should be burned and givin no respect with the technology thats out now adays....

When you control fuel only your timing goes out of whack and you can (most likley will) blow your engine.

Every time you pull fuel you are telling the ecu there is less of a load on the engine and the engine advances timing, yet you are actually at a very high load level. Detonation...boom...boo

[mrturrari]

If you use that basic setup it will give you a decent tune. The reason is that the turbo map sensor uses a different scale then the NA one so at the same manifold pressure it is sending a lower voltage to the ECU. The 315cc injectors compensate for this by adding more fuel at the same duty cycle. The BTM must be added because when you trick the ECU like this it adds timing.

Whatever you do... do not use the stock injectors. At stock fuel pressure they will run out at around 150rwhp which is less then you will make at stock boost pressure.

[Enthalpy]

I will be simply amazed if you get anywhere near stock-like drivability and mileage out of this, if it runs right at all!

Weasy is right, you need better fuel management. As an example, a 2-bar runs out of sensitivity at 14 psi. That means above this boost, you are still fueled as if you are AT this boost. You are COMPLETELY susceptible to overboost destruction in that mode! You need an ECU that will cut boost if you overshoot, which is easily done on some controllers.

The SAFC shouldn't ever be used on a non-Honda. Why? Honda uses a baro-compensated alpha-N scheme for their ignition and a MAP sensor for fueling. The SAFC therefore only adjusts FUELING. On every other car out there (to my knowledge), the SAFC adjust both fueling AND IGNITION. Hence, the afore-mentioned "boom."

The best way (of course) is to use an EMS. Short of that, a really good piggyback like the SMT6 should work, but you will still have issues like overboost.

Lastly, 315 injectors aren't big enough. This will give you roughly 230 crank hp at 100% duty and roughly 11.0 AFR (calculated assuming 0.53 lb/hp-hr BSFC, typical turbo). Most tuners draw the line for safety at 80% duty, which comes out to roughly 185 crank hp.

This means not only can you blow on overboost from the map sensor, you can blow up with the small injectors.

[mrturrari]

This is a tried and true setup that works if you stick exactly to a particular set of components. It has been done by probably hundreds of people over the years and it works if you don't try to cheap out. The 315cc injectors are part of it and are good for about 180rwhp at stock fuel pressure and max boost of 10psi on the 5sfe and stock ECU. If you want more then that you will need fuel control for sure. You must use a gen II 3sgte MAP sensor, 315cc injectors, ct-26 and BTM on a relatively stock 5sfe. It doesn't give you a perfect tune but it gives you a safe tune and a substantial increase in power.

[Enthalpy]

Your and my definition of "safe" differ.

[Weasy2k]

doesn't give you a perfect tune....as in ghetto and unsafe?

I just hate seeing people get frustrated when there engine blows a ring land when it could have been prevented had they known...Your engine may run well sure...but how long will it last? What about if you overheat an injector? The 80% margin is there to reduce that risk by a great deal vs running them at 100%.

Will the injectors fail ALL the time at 100% no...but why risk it?

I will stand by my idea of BASIC fuel tuning Not like the smt6 costs 200X more then the s-afc anyway!

[blackbob]

Maybe there should be more write ups on the 5SFTE job as it seems to be a growing trend. Being a former honda guy the SAFC is all I know for the most part. As for the MR2 looks like the toyota ECUs are a bit different in simplicity.

[Enthalpy]

Honda has always blazed their own path (successfully, I might add) in finding ways to improve engine control. This means they try things other OEMs won't or didn't think of. They are a great engineering case study in engine management.

[mrturrari]

Weasly2k, Enthalpy, I agree with pretty much everything you have said. The 5sfte setup puts you in the same boat as guys who put a t3/t4 on their 3sgte and unplug the map sensor to get that extra boost. You are totally relying on the boost controller and waste gate to do their job. If something fails then you have a problem. Is it ghetto? Hell yeah.

Blackbob makes a good point though that more and more people are trying to turbo their 5sfes. Most I have seen lately are teenagers who have friends who have done it on their cars or have seen others do it on the internet. Most of them can barely afford to buy the turbo kit much less an SMT6 or EMS and pay someone to tune it. They will find a source for information whether it is accurate or not and do it anyway.

[Enthalpy]

Here's how I view the financials of engine modification:

If you can't afford correct control, then you can't afford the consequences (blown engine) of incorrect control. In short, you can't afford the power. Correct electronics costs much less than a rebuilt engine.

Most well-done turbo kits are 2000-4000 (no ebay BS or SSAutoCrap). Most tuned EMSes (save the really expensive ones) are 1500-2000 TUNED.

As an example, if you buy a Nemesis through me, I will tune your setup completely for $200 flat rate. If you want it dyno tuned, it's a $100 adder for the cost of the dyno. That includes battery offset, engine protection, cold and warm operation, drivability, emissions and mileage!

You don't get any of these things from the setup you would have.

[Weasy2k]

PS the smt6 costs 375 the s-afc is not far off! The EMS route through Enthalpy is probably by far the best route...you will SAVE money in the end! Heck the gas milage alone will help :P

[mrturrari]

Financially speaking there is only one way to ensure you don't get in a bind when you start modifying your car... have a backup car.

This is a setup I used to have on my car. I know it works from first hand experience. No you don't get any of those extra things you get for $4000-6000 more. No one ever said you did. After 6 months it was the turbo itself that finally failed because of a poor rebuild and it started leaking through the seals. I drove that car in temps from 10-105F and from 4200-7000ft elevation. I later spun a bearing and had a chance to look at the internals and there were no signs of detonation whatsoever. My engine is now modified past what this setup would work for so I will be putting an EMS and larger turbo on it.

My opinion is that if you want to learn more about turbos and have a backup form of transportation then this is a great opportunity to learn. Actually I would tell anyone who was modifying their car the same thing. Have a backup!

[mrturrari]

Originally Posted by Weasy2k

PS the smt6 costs 375 the s-afc is not far off! The EMS route through Enthalpy is probably by far the best route...you will SAVE money in the end! Heck the gas milage alone will help :P

That is a very good price for as much as the SMT6 does. Definitely better then the SAFC. Unfortunately very few are willing to spend the money to put an EMS on a 5sfe. It's sad because I'm sure we would be seeing a lot more forward movement if they did.

[Weasy2k]

No kidding...5s-fte engines are fun to drive..i love the torque output

[Enthalpy]

Putting a Nemesis on a 5S wouldn't be THAT tough. There's no perceived market, so there's no effort. Perhaps I'm wrong?

By the way, I have no idea where you got 4000-6000. I said 2000 all said and done, full EMS. Weasy said a mere 375 plus tuning for an SMT6.

[Weasy2k]

Thats always the assumption enthalpy....i hear it all the time...

Oh ems? Oh god thats like ANOTHER $5000!

Its not like that anymore people...electronics are getting cheaper!

[mrturrari]

Originally Posted by Enthalpy

Most well-done turbo kits are 2000-4000 (no ebay BS or SSAutoCrap). Most tuned EMSes (save the really expensive ones) are 1500-2000 TUNED.

Sorry, I meant total, not $4000-6000 more. I'm only trying to point out the reality of the situation for most NA owners, not talk about the way things would be in a perfect world. Most people with NA's didn't even pay that much for their car in the place. They are not even considering paying for a turbo kit and an EMS in one fell swoop. So for most this is not even going to be an option... that's the point I am trying to make.

You are probably right that there is no perceived market but it is also an attitude that is being perpetuated, since it is easier to get gains on the 3sgte the 5sfe is somehow an unworthy platform. I believe the market for true performance parts for the 5sfe is lacking because of this mentality. If the 5sfe were the only motor you could get for the mr2 it would be a different story.