Power from 7a, looking for 200 Options

[FallenHero]

Ok, I have set my power goal for my 7a at 200 hp at the wheels.

Now the question is, how?

The obvious answer from most is 'slap on a turbo.' but that's not what I want to hear.

I am going to re-build my engine soon. Here is my plan:

Re-build enging to brand ,new stock condition + a 1.8-2.0mm head gasket to lower compression a hair. Then, underdrive pully, and retard the timing a hair with adjustable cam gears for a 'rolla. Turbocharger +large FMIC and about ten pounds of boost.(maybe up to 14psi).

I have also thought about calling up jet and having the rev-limiter on my car raised up to 6500-6800. What do you guys think about that?

So, with proper tuning and electronics, what kind of power output do yall think I'd get? I have seen turbo 7a's pulling 170ish, So I have high hopes.

keep in mind I am thinking outloud here so...

Thanks for reading.

Jon

[Coomer]

Sounds like a good plan, and I think you should be able to hit 200 horsepower with enough boost. While rebuilding, I'm not sure how much extra it'd cost, but I'd definitely think about maybe using parts that are stronger than stock, because running 14 PSI will but quite a strain on new OEM parts.

[5sfeTurbo]

Good stuff, like coomer said running 10-14 pounds will call for slightly stronger than stock. The ECU sounds solid never really read into that other than piggy backs. Good fuel pump, headgasket, apr studs would be a start. Dont see why 200 couldnt be reached.

[zipstrips]

200hp is a good atainable number. but stock intrenals at 14psi will not last long... personal experience, u need to upgrade the pistons, than the next weak link is the rods..the underdrive is a nice touch. i am rebuilding my 7a for future boosting, but for now my research has come to this. turbo kit and stock internals 7psi is the limit unless u dont want the motor to stay long.(unless u like replacing the landrings and possible more every 2 or 3days..) new fuel pump is a must along with a RR FPR. the t3/t04b hybrid that is popular is good if/when u rebuild with forged internals, until than a basic t3 will flow enough, make sure it is properly intercooler thou. stock injectors are fine for 7, tuning this motor is the biggest step.. i am looking to a piggyback now other than the safc.. the dsm guys seem to be having great sucess self tuning so i am looking for them to help with emanage or aem or another system i have not looked into yet.

[FallenHero]

Where would I find forged pistons that I wouldn't need custom rods?

That was my big problem. Forged pistons cost, but not nearly as much as custom rods...

And I figure a supra fuel pump would work, if I can't get a nice aftermarket unit cheap.

Also, I have heard the 7a head makes the engine smoke a little under boost. Any suggestions other than the re-build? I actually thought about a 4a head swap,but the wiring and manifold set up would be a pain.

[zipstrips]

[97sccelica]

i think crower does custom rods for $700

use a set of 4agze low compression pistons.

maybe find a way to modify the block to have oil squirters, that would really help with engine life.

as for the smoke problem, it comes from a few things. mainly its the high oil pressure that the 7afe oil pump makes.

i think my engine is running into trouble. when i start it up, condensation and soot are shot out of the exhaust and stains the concrete.

i have a feeling something was damaged when my fuel pump died causeing the car to run extremely lean

car goes in to toyota to be checked out under warranty on thursday

i hated having to take all the parts off of my car, but if something is wrong internally, at least i wont have to pay for it!!

[doGGy]

4A-GZE low comp pistons will fit to your 7A rods with a little modification to the pin insert in the rod.. Im doing this to my 7A, and i will be using 4A-GZE pistons. Next thing - go with the Greddy E-manage system (with full wiring like injectors wiring, MAP wiring (and new Greddy MAP), Ignition wiring.) it will be easyer for you to set up your car. DONT USE FMU just get good FRP adjustible by hand and from boost, get good boost controler, good 3ple metal head gasket, lots of gauges and you'll be set to go. And dont overate your engine (14 psi??) cuz it may blow one day.. I think i will be riding with whole new internals, mods to the crank/flywheel/pistons/rods and etc. at about 10 psi daily. I will let ya know how everything turn out

[SpedToe169]

Doggy is right. I would highly recommend the e-manage because of the ignition control it provides. Its a cheap and proven system.

Do not lower the compression!! It is a common mis-conception that this makes more power on a turbo car because you can boost higher. This is true in an all out race engine, but in a street engine driveability will suffer greatly with the lower comp ratio. DON'T DO IT!! Boost response is very important in a street engine and lowering the compression is one of the many things that will mess it up.

Do everything you can throughout the build to prevent detonation! Prepare the chambers correctly, make sure there are no hot spots anywhere in the chamber or on the piston crown. Make sure the valves are ground correctly as well as the valve seats.

Don't waste your time and money on cams. The 7a cams are actually quite good for turbo applications. You will not find any gains with aftermarket or custom cams until you reach about the 400hp mark. Focus on detonation prevention and tuning.

The bottom end is structurally strong enough to withstand 200hp. The pistons are a weak link as everyone has said but as long as you're always mindful of detonation, have the car tuned correctly, and install some failsafes incase of loss of fuel pressure or other disaster, then you'll be fine.

If you're building a motor I suggest that you use the stock crank and rods with custom aftermarket pistons (about $400). Leave the compression ration around 9-9.5, no lower. Make sure that whoever makes the piston knows its for a turbo application and has worked with turbocharged engines before. Have the rods and crank shotpeened and beam polish the rods. Have the block checked for straightness and squareness (all the bores parallel, the crank perpendictular, etc). Have EVERYTHING magnafluxed to check for cracks and stress risers. This should be good for somewhere around 275hp at the crank.

Pay special attention to flow throughout the system. Make sure that everything is portmatched, porting isn't really necessary but some cleanup around the valve seat and de-shrouding of the valve will help a lot. DON'T make the ports bigger!! Just take the rough stuff off and clean up around the valve. Make sure all your charge tubes have smooth bends and transitions. Work done to help smooth flow will help the engine out greatly. It will reduce pumping losses and allow you to run more boost without detonation.

Theres a lot more I could go on about but its been covered before. There are 2 books you absolutely MUST read if you want to do this right. Maximum Boost by Corky Bell and Forced Induction Performance Tuning by A. Graham Bell. These two books will answer almost all your questions and tell you everything you need to know to do this right. Don't be lazy!!!!! Read them!!!!

[FallenHero]

Don't worry, those two books are the first two parts of my turbo set up I plan to buy

Also:Doggy, are you saying that 4agze pistons will fit 7a rods with the help of a good maching shop???????? Because that would save me some serious money.

If not, I found these guys last night. They look promising.

http://www.ariaspistons.com/

EDIT: I also have an auto tranny. I am told it will hold 200hp, but I doubt anybody really knows. I was thinking I would purchase a new torque converter that was more performance oriented.

This post has been edited by FallenHero: Jan 7, 2004 - 11:16 AM

[97sccelica]

the torque converter would not be the weak part of the ST auto tranny.

but the auto tranny should be stronger than the manual tranny because the parts inside are bigger

you could get a new auto tranny, that would help, or you could have you tranny rebuild with performance in mind www.level10.com

[SpedToe169]

Arias does great work. The GZE pistons should fit fine with a little machine work but by the time you buy them and have them machined....the costs may be similar.

[RedSunCelica]

Dang i though i was the only person crazy enough to tune a 7a motor. good luck with the turbo project as for me im going to see how much power i can squeeze out of a NA 7A.

[FallenHero]

Na? you must want some CRAZY compression!
And as for the GZE pistons... If I couldn't get the for $50 off of ebay, I would get the Arias ones. After all, ten year old machined pistons won't be as good as aftermarket ones.

Thanks for the tranny link... but it's a speakers web page. I get the Idea though, and will go and look.

This post has been edited by FallenHero: Jan 7, 2004 - 11:14 PM

[aaronc222]

[5sfeTurbo]

yea the TC is a great idea but the re-built tranny is for like 500hp at the least and $3,000 bucks but if your really booostin then why not have to ever worry bout the tranny...

[FallenHero]

Yea, I found the web page with Ask.com

My main reasoning was this: If atmospheric pressure is a little over 14, then 14psi of boost would double the output of the engine. I figure If I run ten and get all the accessories (under drive, cleaning up the intake manifold like evilspeed, nice plugs/wires, portmatching, and properintercooling) I should be good to go for 200 at the wheels

I might even get that ground wire kit one of these days, lol!

[97sccelica]

[SpedToe169]

[FallenHero]

lol, they said that 14psi doubled power a while back in one of theturbotech sections of SCC. I checked on your book today ($35!) looks like I will begg my local library to get it!

Jon

By the By, that 20v 7age rocks!

http://www.autospeed.com/cms/A_0666/article.html

He's boosting 18psi. So would 12lbs of boost be pushing it with GZE pistons?

This post has been edited by FallenHero: Jan 8, 2004 - 10:50 PM