My Street Ported 12A Blowthrough Turbo
 

Just to keep thing in order I just wanted to thank Rotary Shack (Robert) for all the help tips parts and great prices and great customer service. Put it this way he got me through the build and I never even drove a turbo car before much less built one.

Heres a run down...
Rebuilt 12A mild street port
Boost Preped Mikuni (Still tweaking pilot Jets)
CX Racing I/C Pipes
Short NPR Intercooler
Malpassi boost referenced regulator
GSL SE Pump
Racing Beat Racing Pressure Plate
Racing Beat 3" Down Pipe Welded onto a Y pipe mating up to the RB Street Port exhaust system (frankendownpipe)
PLXM250 Wideband
Oil Pressure / Temp / Boost and Water Temp guages
Working on my lexan console guage holder (with Rotary Shacks rotor decal)
S4 Turbo with ported wastegate and twin scroll (no boost creep)
S4 Stock manifold spaced out using 2 exhaust spacers and gaskets (longer studs)
Ebay special BOV sounds great

She is the fastest thing I have driven. Scary is that it's only on 5psi.... I'm not sure I want 10psi. I'm working on a bog and leaning out outside of boost (jets on order) but I'm pleased. Also need to install a larger return line to improve flow.

Thanks to Ben, Steve, and Bad83 to.

Videos to come...

Welcome to the club glad i could help!

Dude! Nice. Glad to see another 12A turbo in the group! Good job. Get us a vid as soon as you can!

Robert sure seems to know his shit with these projects!

cool i would like to see more pics please.

i cant wait to join the club lol

You say it's the fastest thing you've ever driven with only 5PSI?? =O

How fast is it? What is the 0-60mph time? Top speed? When does your boost kick in with the S4 Turbo?

Also..i was about to ask about twin scroll and what it is but i'm off to search. =]

That looks like a really amazing setup. I'm sure it does fly. It really doesn't take a terrible amount of horsepower to make these cars quick.

Yep add a little power to some cars and they feel amazing http://www.youtube.com/watch?v=0lys5Gru-NE Put a 13b n/a in a 12a rx7 that you've been driving for years and it'll "feel" like a rocket.

I get to 5 psi of boost in 1st at about 3K.

Still havent timed it yet or ran it up to top speed. Now I kind of get tunnel vision on the road whenever it slams me back. Need to get more comfortable with it because quite frankly its scary now. I mean I ran NA with my street port and I was doing well enough to wax most of the ricers now it's a whole different thing. I have a 300hp Q45 (I know its heavy) but I could run circles around it now.


What I called the twin scroll is the S4 exhaust side of the turbo... it has a flapper that covers the smaller of 2 exhaust ports feeding the hot side of the turbo. In its original design this flapper stayed closed till a certain point and then an actuator would open it with the intentions of making the turbo spool faster. A common modification is to cut the flapper door out leaving the smaller port constantly open as well as match the size to the larger port. The net result is that both are constantly open and are equal in size to increase flow efficiency.

Heres some more pics on the build.

http://rx7learner.pictiger.com/images/

I did not use the bov in the pics on the link.

Very nice. I agree some videos are a must. I will be giving a nice street port to the 12A for my FB and eventually will add my S5 turbo to it.

HAh well dang..gotta pull my engine soon. I was going to just buy a 13B with SP and turbo but maybe i should just stick with the 12A and boost it?
If you guys had the choice between:

Boosted SP 12A

or

Boosted SP 13B

Which one? =P I know most people would say at first glance the 13B because it's bigger but is there any advantages with going 12A instead?

^^13B. Hands down, even though I am a 12a guy :(


Engine looks nice! Can't wait to see some #'s!

Hmmm another interesting question that i have..

A FB with a 13BT SP would have to make how much power to be faster than a stock FD? Keep in mind only straight line, since FD's suspension are amazing compared to our straight axle. =[

What's the lbs per horsepower ratio? I.E. how many pounds or ounces do you need to gain or lose to make or lose one horse?

To beat a stock FB with a 13B Turbo, you would only need relatively mild mods on a stockport motor. Now if the 13B Turbo is street ported, all you really need is the stuff you would need anyway, ie. exhaust, boost controller, ported wastegate, FMIC, and good tune. I like the idea of boosting the 12A just because it's the motor that came with the car and even though more people are doing it these days, I still think it's more unique. Plus, as Robert has showed us, the 12A is capable of making just as much power as the 13B does

i will tell yah this much i will smoke a stock T2 in a heart beat lol. Other than that i don't know lol.

thats a nice build... did you change the hard fuel lines to something bigger?

No I used the stock lines however I will be switching to a larger return line this weekend. I am able to get down to 5psi base pressure at idle but dont want the additional stress on the fuel pump.

I was going to get my 0-60 time but my dumb speedo went out. It's either dead or the problems behind the cluster cause (I checked the cable and how it's screwed into the tranny.)

As far as trying to decide 13BT off the shelf or 12A you can find many posts that say the 13BT swap is cheaper but I find it depends.

My personal experience is that there are expenses I would have encountered either way 13BT or 12A blowthrough. Custom down pipe and exhaust, Intercooler, Intercooler pipes, guages, wideband and fuel pump. (provided you didnt want to use the stock 13BT top mount IC)

The things I wouldnt have needed if I bought a 13BT off the shelf is (carb hat, S4 turbo and mani, exhaust spacers, and boost refrenced reg) part of which could be offset by whatever you need to buy in order to drop in a 13BT into our cars.

The one major difference is that you are paying around 1200$ for a used 13BT tranny harness & ecu. I knew the condition of my 12A... I just rebuilt it... and my tranny is fresh.

After the tally I honestly think if you have a good running setup... going blowthrough may be slightly cheaper but it depends on what you start with as a baseline.

However

If it's less tuning and debugging you are looking for... get the 13BT...

I just like to be unique.

I know all this can be debated till 2030 but thats why it's qualified with... my personal experience.


OOOOH also regarding the TII versus a 12A blowthrough the other consideration would be the weight difference... I think (not sure) somewhere around 400 lbs... If anyone knows for sure chime in.....

I will destroy a t2 fc DESTROY!!! in stock form anyway!

As an owner/driver of a TII swapped GSL-SE, I can say that either way you go is fine. If I had a 12A car, I would have put a Turbo on it versus changing to the TII. Cost is the biggest issue. The only reason I didn't use my stock 13B was because it was a 6 port and I didn't want to turbo a 6 port motor. Knowing what I know now, I would do things differently due to all the $$$$$$ that went into my project and yet I still have ALOT more spending to do...
Brake upgrade (mandatory)
Upgraded axles (mandatory)
BFG Drag Radials( NOW Necessary)
etc...etc...etc...

P.S
YES they are SCARY with all the power a turbo adds to a 1st Gen. I can't seem to get all of my 383 HP's to the ground and from a roll..... she pulls like a frieght train... and scares the S*%T out of me...

L8R

On the Expressway I will keep up if not walk on many TII's and FD's.
My power to weight ratio is CRAZY....:lol:

L8R

That's a hell of a motro you buildt ther,I like when people do thing's in a nice mater.have fun a keep up the great looking work.

does the a/c still work??? lookin great!!!

ok thanks... im also using a gsl-se pump for my build and wasn't shure about the fuel lines. congrats. on your car. :)

I know next to nothing about turbos, so this may be dumb but what are these s4 and s5 turbos your talking about????? Thanks for putting up with a turbo noob! lol :)