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Discussion Starter #1
So i have my 5sfte in the works my entire engine is being rebuilt with 87.50mm enginetec pistons, stock 3s rods, i have a gen 2 3s map sensor otw, msd btm 5462 with tach adapter and a water methanol kit also im going to order 315 supra injectors and i am dropping in a walbro fuel pump since i have everything opened up anyways. I also have delta cams bolt in option and 3s std valves, springs, and retainers etc. Now my question is that with all that will my injectors still be enough to supply my mods i know the basic 5sfte setup has less then some of the mods i have but since they are all bolt in options will i still be in thr clear or do i have to go with a stand alone and bigger injectors? Ive searched the specifics on other websites including camry and celica forums but nothing to my specifics any advice or input will be appreciated
 

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315cc injectors? A stock GEN2 3SGTE uses 450cc injectors. I'd say if that number is right, they are far too small. Even the 3SGE uses 295cc and 330cc or bigger as they got newer.
 

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Injectors are sized based on power output of the engine. A 4 cylinder needs approx 150cc/min per 100 crank horsepower.
 

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Discussion Starter #4
315cc injectors? A stock GEN2 3SGTE uses 450cc injectors. I'd say if that number is right, they are far too small. Even the 3SGE uses 295cc and 330cc or bigger as they got newer.
Yes 315cc got that from mr turraris write ups on building a 5sfte i dont plan on running high boost like the 3sgte which according to info i found here that a stock 3s pushes about 11ish psi because it has a tvis while a 5sfte with a ct26 said it will push between 6 and 8 and im under the assumption that since the stock 5sfe injectors can handle bolt in cams maybe with a low boost agenda the na supra injectors will still be sufficient?
 

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Seems a bit small to be safe even at low boost levels. And you would need a stand alone ECU to control all of this. The 5SFE ECU doesn't know what boost is and ANY injector size change will throw it off.
 

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Discussion Starter #8
Does anyone know what happened to mr turrari because it seems i only get 3s enthusiast and i would like advice from someone who has hands on or personal experience with building a 5s
 

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Well, no, I haven't but if you are asking and you are telling us we are wrong then it's obvious you know exactly what you are doing. Just trying to help here Sir.
The 3S and 5S aren't really much different and if you are boosting an engine you want a healthy supply of fuel, it doesn't matter what engine it is.
 

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Discussion Starter #11
Well look man i appreciate your attempt to help but if you dont know if what your saying is accurate then please refrain from responding because all the info i presented for further advice is mostly from this website or the celica 6gc forum thats why i payed for my membership so i can read all the info there was to offer. I think its sad that when i read back to the earlier days of this website people were helpful and backed up their input with facts and trial and error not just a guess based on what you guys think. Thanks for all the help this year but it seems this websites moral is low and people cant take constructive criticism without getting their panties in a bunch.
 

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Discussion Starter #12
Based on my 4age turbo running 440cc injectors at 72% max duty, you're hosed running 315's on a 5s.
I see discussion where people say to use the rx7 (i believ 460cc) injectors but theres a lot of people claiming on fully detailed right ups where they say the 315s are sufficient. So i guess im just kind of stumped on where i should be at with my fuel because of write ups that claim na supra injectors will work.
 

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Well look man i appreciate your attempt to help but if you dont know if what your saying is accurate then please refrain from responding because all the info i presented for further advice is mostly from this website or the celica 6gc forum thats why i payed for my membership so i can read all the info there was to offer. I think its sad that when i read back to the earlier days of this website people were helpful and backed up their input with facts and trial and error not just a guess based on what you guys think. Thanks for all the help this year but it seems this websites moral is low and people cant take constructive criticism without getting their panties in a bunch.
Fair enough. Point taken.
 

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The number you really need to figure out is how much power you want. If you want 175 crank horsepower or less, the 315's will be on the ragged edge. If you're going for 250, then you'll need bigger injectors. 5S, 3S, 4A, 2GR, doesn't matter, fuel injectors are sized for the power you want to make and the number of injectors you have.
 

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I am afraid there are too many mods to your engine to be using the 315cc injectors and MSD on the stock ECU without tuning. Also I only fully trust that original setup on a stock 93+ 5sfe with the knock sensor so would recommend anyone with a 91-92 add in at least a fuel and timing black box. With tuning you can probably keep the boost low and still use the 315cc injectors but the amount will need to be determined when it is tuned. The cams and valves are going to bring the boost the 315s will support down because you will be making a more power in the upper RPMs with less boost. Also if you use 460cc injectors and have emissions in your area be aware that a black box cannot bring the AFR anywhere close to 14.7:1 at idle. It would be great if someone found something in between but I haven't seen anything from a stock car.
 

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Discussion Starter #16
I am afraid there are too many mods to your engine to be using the 315cc injectors and MSD on the stock ECU without tuning. Also I only fully trust that original setup on a stock 93+ 5sfe with the knock sensor so would recommend anyone with a 91-92 add in at least a fuel and timing black box. With tuning you can probably keep the boost low and still use the 315cc injectors but the amount will need to be determined when it is tuned. The cams and valves are going to bring the boost the 315s will support down because you will be making a more power in the upper RPMs with less boost. Also if you use 460cc injectors and have emissions in your area be aware that a black box cannot bring the AFR anywhere close to 14.7:1 at idle. It would be great if someone found something in between but I haven't seen anything from a stock car.
I had a feeling i overshot my original target so at this point im assuming i should just use my megasquirt 2 or just stick to an NA build for now?
 

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I’m not a huge MS fan, but it’s so so so much better than flying blind on a factory NA ECU. I’ve got a 2nd gen 3S-GTE MS PNP2 with a dead inj driver(or something in the circuit) I’ll sell for super cheap.

FWIW, 315cc inj on a 4 banger is good for about 180-190 rwhp Max’d out with a good fuel pump behind them. That’s not a safe level, that’s a completely wide open level. Safe is probably 10-15 rwhp less.
 

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I had a feeling i overshot my original target so at this point im assuming i should just use my megasquirt 2 or just stick to an NA build for now?
I was one of those people from 6GC.net that built a good running 5S-FTE back in the mid-2000's. Some of us did use 315cc injectors at first but they really weren't large enough and we all outgrew them pretty quickly. I believe I used red, high impedance RX-7 injectors, although I can't really remember what size they were now. You definitely need some form of knock monitoring. Our engines were all 94+. (My specific engine was a low mileage 1999 5S-FE so knock sensor and MHG standard)
I'm not here to dissuade you from your project, but it is worth mentioning that every single one of us eventually swapped to 3S-GTE.

edit: 460cc injectors High Impedence
73168
 

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315cc is too small for a turbo application. You'll run out of injector far before you will see any advantages to your build.

if you're looking at stock injectors, look at USDM supra turbo injectors. They are 550cc and will give you a bit of headroom for boost/mods.
 

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315cc is too small for a turbo application. You'll run out of injector far before you will see any advantages to your build.

if you're looking at stock injectors, look at USDM supra turbo injectors. They are 550cc and will give you a bit of headroom for boost/mods.
He needs top feed injectors, the supra 550's are side feed.
 
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