I'm looking to replace the stock turbo on a 89-91 model engine that is completely stock with a t04s turbo with 60trim. What kind of horsepower can a expect with this set-up?

 

350HP on reasonable boost levels. 400 if you turn the boost up a bit higher.

Note of course that you will need a full standalone and all the other appropriate modifications to run this turbo.

 

So is it the ECU that won't work with this set-up? and what is it about that turbo that requires a full stand alone system? i'm totally new to all this electrical engine stuff so i'm looking to learn a lot on here. Thanks for the info!

 

The ecu is so you can get a good tune so you don't blow your engine with all that power, and control things like the wastegate, get rid of the afm (very restrictive), etc. This is also so you can control the upgraded fuel system you are going to need to install.

 

Sweet... That makes perfect sense. So does anyone have any recommendations on a good standalone system and possibly what size injectors/fuel pump? Keep in mind i am a college kid on a very tight budget! Also, i forgot to mention earlier that this engine is being installed in a '76 MGB so i'm also needing info on hooking up electrical to just get the engine running and drivable once its in the car.

 

ok so i've done a little research on standalone systems and they are looking waaaaay out of my price range for this project so i guess my next question would be what is the best turbo to use that would not give me so much power that i would need an upgraded ECU or fuel system? Somewhere in the 200hp range which i think is about stock.

 

you say your a college kid on a tight budget right. What power goals are you aiming for ? Stock power, above stock power, double than stock power ???

 

it sounds like you should just stick with the stock turbo and do supporting mods like an FMIC and upgraded radiator. then you can get injectors and an rtek 1.7 ECU upgrade and you will make like 220-250rwhp. that's what i had on stock turbo, and I could beat stock 350Z's and STi's

 

220-250hp would be perfect. i have the stock turbo that came with the engine but its pretty worn out. we took it to a turbo repair shop and the repair cost is the same if not more than buying a new turbo off ebay, but the only ones i can find on there all seem to be high horsepower. There are some cheap ones in the $250 range so i'm skeptical.

 

Hey bud just a suggestion, the turbo should give you enouph air flow for 475 to 500, but not with the stock ports you will be limeted to around 400, that is also if you upgrade fuel injectors,computer (standalone)fuel pump(255lph) down pipe exaust air intake, good luck hope that gives you a guide.

 

ok so i did some research and it looks like what arghx suggested is a great set-up in my price range. Is there a difference between the primary and secondary injectors or will i be ok just buying 2 720cc injectors? Also which injectors are the secondary ones on the engine? As you can tell I know nothing about rotary engines or fuel injection systems! I'm an old school carbureted piston engine and motorcycle mechanic guy!

 

I just thought of another question... Could i use one of those T70 or t04s turbos and just run them at low boost, like 9 or less? that way i don't have to do any expensive upgrades like a standalone, porting, etc?

 

No difference on tt primary or secondary in cc, primary injectors are located on the engine on the itermidiate housing (center plate),secondary injectors are located on the intake manifold,they are 550 cc and are high impedense injectors,
But for 225 to 250hp upgrade air intake and a high flow exaust,a 255 lph fuel pump and a good 89 and up turbo bring the boost 10 to 12 psi and you should get the power you need with out a computer and a fuel cut defencer, the stock computer cuts fuel at about 14 psi but if its cold weather it might be alittle lower psi.

 

No don't get either one those no need ,just use a good reliable 89 and up fc turbo, you will be fine.You might be more limted only because of $.

 

Sweet. So no need for an injector upgrade right? and when you say an intake upgrade are you talking just a cold air intake or going as far as removing the mass air flow sensor or what?

 

NO ,not for that power, cold air or open element air filter,no do not remove air flow sensor that is an important feature for your computer to meter air flow and air temp.

 

Great! So now all i have to do is locate another stock turbo or an equivalent, which i am having trouble doing. There are several turbos for an rx7 on ebay for $300 or less, but they all seem to be high horsepower turbos. But because of their price i am skeptical of their actual performance and wonder if maybe they would actually perform close to the stock turbo.

 

Not sure I'd trust Ebay for something as crucial as the turbo... especially at only $300...
Look into BNR turbos, they'll rebuild your current turbo (don't have to buy a new one) and convert it to a hybrid turbo (if you want it). Really good price-to-power ratio. That also enables you to keep the stock exhaust manifold and exhaust piping, and you don't have to deal with custom fabricating for an external wastegate. You can even make very good power with them in the future, like 350whp on a stage 3 hybrid.
With this setup you're probably going to want to consider an Rtek 2.1 - pretty decent tuning ability or much less than a standalone.

 

A bit off the subject but whats the best setup as far as boost controllers go? I'm pretty sure thats what caused my turbo to go, Only mods were 3 in. exhaust w/ no cat only silencer and a racing beat fuel cut controller. I was looking at the HKS vbc since its the cheapest and highest quality i can afford right now.

 

What?!?
the stock ecu cuts fuel around 8psi. If you just turn up the boost without a FCD and higher flow injectors you're going to blow your engine really quick.
At the VERY LEAST I would recommend 720cc secondaries, a FCD, a 225lph pump (at least that was right), and a SAFC to up the fuel.
Or you could do a rtek 1.8, throw in 720cc all around, and not worry about the FCD or SAFC.

 

Going with an Rtek 1.7 w/ 720cc secondaries & a walbro (hi flow, non-ebay cheapo version) or other pump (FD pump in my case) will be all you need to max out the stock turbo. ~12 psi will put you around ~250whp, as mentioned, and will launch that 2700lb. MGB just fine .

For the turbo itself, I'd suggest porting the wastegate. If you're going to have a good 2.5-3" open turbo-back exhaust, you'll get boost creep above your setting, which will lead to a shorter turbo life. With the extra fuel, you probably won't blow the engine, but the stock turbo's bearings don't respond well to more than about ~12psi on a regular basis.

When selecting the 720cc injectors, they'll likely be low impedence, so resistors will have to be wired in (S5s use high impedence). A pair of 6-10ohm, 10-20W resistors will work for this, and can be wired in where the injector wires meet the ECU. Here's an example of some denso low imp. 720s: http://www.rx7store.net/product_p/greddy%20720cc.htm