im doing a turbo project on my 88 gxl. I am looking to buy a turbo and manifold. I have found plenty of s4 turbos and they are a lot cheaper than the few s5 turbos i have found. What should i do? Should i get the s4 turbo and manifold? or should i hold out for the s5? what are the differences and how much potential does each have?

Thnx yall
-Tommy-

 

so are u going to put a turbo In the NA engine? or a full T2 Engine swap?

 

turbo on an n/a.

 

I see well S5 turbos are better then S4's so that makes them harder to come by.
a better bet will be Just doing a full T2 Swap if your looking for True somewhat reliable power.

By doing a T2 swap It will save you Money and Headaches on the end, NA's are not meant to be Boosted unless you do some Work to them first and expend some money by having to do Bigger ports and prepearing it to get abused so it dosent blow the first time you run it.

Personaly i would not do it, but if thats the way you want to go Goodluck.

Thers a Ton on info on this Subjet Just search around.

 

Yeah,, i hear that. Ive switched back and fourth making the decision. Im just so confused. IF i did swap for a t2, would that motor mount without modifications, and will the n/a trans fit right.

 

ok... well, judging that your car is a S4. get a T2 S4 motor, it will be a direct swap. if you get a S5 T2, good luck... different mounts. dont mate it with the NA tranny, it wont withstand the T2 motor in the long run. get a T2 tranny and go buy a mazdatrix driveshaft made for T2 tranny to NA diff.

if your going to turbo, i hear and know its best to go S5 turbo + manifold. the S5 turbo has a bigger waste gate. which allows better boost. the S4 has a small dime wastegate which sucks *** as i hear. although it seems that way, you go here: http://www.bnrturbos.com/2ndGen.htm

this is where upgrade the stock turbo. they say the S4 yields better results here than the S5. but hey, good luck and search around for more answers and its good to ask for help but make sure its not the same questions that have been asked before.

 

The S5 turbo has a much larger wastegate and a fully divided turbine housing. This gets rid of the twin scroll actuator and flap that the S4 uses. Other than that, they're the same.

All FC motors have the same mounting points and share the same transmission bolt pattern.

 

Oh heck yeah dude. Ive found lots of threads like this, but sometimes if you ask the same question in a different way, you find different/better answers

 

I have a 86 GXL with a Complete Jspec S4 T2 Swap everything bolts right on, but you wil need a T2 tranny too and to swap the rest of the Drivetrain is a very good idea, u dont want to leave the weak rearend driveshaft to fail later on.

U can eighte modify the Harness or the simple solution will be to install a T2 harness in the chassis.

Im in the process to port the Wastegate, its the only flaw i see with the S4 tubo setup.

 

Using the NA engine harness is far easier than swapping in a TII harness. Cut the wire at the knock sensor pin, extend the BAC & TPS wires and you're done. It was incredibly easy in my turbo convertible.

 

Do you have a dremel tool or access to a machine shop? If you port the wastegate on the S4 then the difference won't be that big..S5 will hit boost slightly earlier and flow a little better, it really depends on the price difference.

Why would he have to port the engine? And what do you mean by "preparing it to get abused?" This would need to be done with any engine. Keep the NA and boost it unless it has low compression. The 6 port seutp at 12psi will yield more power than the TII and have a lower boost threshold.

 

yeah i have a dremal tool. What type of bit should i use. and what are the chances of blowing my engine? Please only answer the question if you truly know, dont just give me what you think would happen.... thnx.

 

If you go to Aaroncake.net and go to modifications>S4 turbo extreme wastegate porting you can see a pic of what bits he used. You will need a cone shaped stone and one of the cylinder shaped shank things with the lowest grit sandpaper you can get, walmart has it. Be patient, it takes a while.

Whether or not you blow your engine is entirely up to you and the condition of the engine as it sits. Does it smoke? hows the compression? does it accelerate normally?

Don't worry about the high compression rotors or the fact that it is a 6 port engine. There are tons of 13BT/13B-REWs with 9.4:1 and 9.7:1 rotors running big turbos and 15psi+ with over 400whp. The ports on a 6 port are slightly bigger if anything than the stock TII ports, with port timing being only slightly unfavorable for boost. If you go to the single turbo section and search posts for "6 port" you can find proof and more info on all this.

FYI I just did boosted my stock S5 NA engine after putting 40K miles on a Kevin Landers rebuild. Currently running 6-8psi awaiting an EMS and AI.