My car's got 150k miles, and the compression isn't exactly awesome anymore. I want more power anyway. I'm thinking that I'll either rebuild and port mine (the NA path), or buy an old junked TII s4 or s5 and rip the engine and everything out and rebuild it+port it (the turbo path). Obviously the NA path is easier, but which is the better value for the money? Is it difficult to put the TII ecu into an NA? What's the best 1/4 time I could get on a streetable NA?

best value for money is turboII path, presuming you don't blow up the engine and get enough use out of it.

the 89-91 ecus interchange except for 2 wires, basically as long as you do everything 89-91 it will fit



mike

Turbo

You might as well go TII https://www.nopistons.com/forums/pub...#>/biggrin.png

the only problem is that s5 t2's are fairly rare, right? Do you have to rewire your dash if you put in an s4? Oh yeah, what specifically made the s5 t2s have more power?

the easiest path to t2 power is a j spec motor, they come with the turbo, intake, injectors etc. you will prolly want to rebuild the j spec motor though



mike

I do want to pass emissions. Can I put stuff like the ACV on a jspec?

the jspec has all that stuff, so yes you can



mike

If I was in the market for a j-spec S4 TII motor, what would I expect to pay? Mine's fine, but I noticed a bit of what appeared to be oil in the coolant when I changed the antifreeze this fall. Maybe not oil, but some kind of black sludge was left on the bottom of the bucket when I poured out the old coolant at the recycle station at the county landfill.

there is almost no way for the rotary to mix coolant and oil



mike

Few things to say on this matter:



I disagree with you all, lol. Honestly, yes Turbo is more fun and faster, but it is more expensive, not as reliable and cuases many headaches. If you buy a blown T2 and rebuild its motor..thats cool, but converting NA to T2 isn't all its cracked up to be, lol.



Second...JSPECS SUCK ASS!



Third...if your looking for an S4 jspec motor, your looking to pay from $600 to $900 plus about $120 in shipping(motor freight).



Fourth..the jspecs to have the emissions equip already on them, so like jd said..you wont have to worry about the ACV, air pump...yada yada..



Fifth...you SHOULDNT have to change your dash harness when converting, but I did, lol...



Finally...an NA streetable car w/ an NA built motor can easily run low 13s..I've seen it...then again you can always sacrifice a little streetability for speed and run 12s w/ an NA street car...but we're talkin hella motor/driveline build, lol...



To sum myself up...either buy the T2 and rebuild it...or build up your NA GTUs, conversions are bad..mmmkay.*





*=my opinions are very swayed by personally experience, your results may vary :bigok:

* https://www.nopistons.com/forums/pub...#>/biggrin.png



ps. TURBO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!

pss TURBO!!!! ALL BOW TO THE TURBO!!!!!!!!! https://www.nopistons.com/forums/pub...IR#>/boink.gif https://www.nopistons.com/forums/pub...1047683894.gif https://www.nopistons.com/forums/pub...1047683894.gif https://www.nopistons.com/forums/pub...1047683894.gif https://www.nopistons.com/forums/pub...1047683894.gif https://www.nopistons.com/forums/pub...1047683894.gif

Ive been thinking of turboing my vert lately but i've also been thinking of selling it.

that would be awesome

so say you paid 900 plus 150 shipping plus 400 to rebuild.... isn't that a good deal for a practically brand new turbo engine?

900+150 to get an iffy motor + 2000 for a rebuild. But if you rebuild it urself it can be much much cheaper, IF all the parts inside are good.

Yea...gotta remember..they SAY the jspec has 20K or so miles, but there is no proof...I for one am now an avid Jspec H8TR!!! The one i got had a totally worn out stock clutch, so i nkow that it was either driven a lot, or driven hard...both arent good..thats why it ran like **** when i had it installed. Also, i paid 1000 for my S5 Jspec mtoor plus 500 for a tranny w/ 12K on it, and then 190 for shipping...

Hey Seppuku, where'd you get that gif in your sig? That's so cool.

It was posted up in gen d in a topic called cool avatar or something like that. I just snagged it.

why not just rebuild your NA motor, street port it, get hardened stationary gears, do some oil modifications and such, then just make a bad little NA with some weight reductions? Would be cheaper than doing a TurboII swap. And after that just concentrate on improving the suspension, get some light wheels and tires...



There are plenty of modifications desirable on both NA and TurboII's, like the flywheel/clutch/pressure plate, suspension, wheels/tires, weight reductions, electric fan, porting, PS, AC, and emissions removal... SS oil cooler lines, aluminum radiator, fuel system (this one is alot more elaborate on the TurboII's too)...



choosing to swap in stock TurboII components FIRST will just add a bunch of time to your buildup, and increase the overall cost, if you want to do the above modifications also (most of which you are probably interested in)



If you just rebuild the NA and port it, you can keep your ECU, and your trans etc. And move on to the rest of the things and in the end have a much more complete/refined car. Unless you have tons of cash, and can afford all the mods in addition to FMIC, POV, BOV, jspec + rebuild + port, TurboII trans, driveshaft, rearend and axles... possible turbo rebuild kit or new turbo, TurnboII aftermarket exhaust parts. Which would certainly be a faster car, but the pricetag is much higher. I personally feel one could get a much more refined and better overall performing car going the NA route instead of the TurboII conversion route, for the same amount of money (presuming the amount of money is reasonable and enforces spending limits)



just my $.02



not to mention you're alot more likely to blow up if you go Turbo. Even if you take all the necessary steps, **** happens. injector fails, air in the fuel line (low tank of gas? no, it's not likely that 13 year old fuel gauge isnt accurate :squint: ) maybe that used TurboII harness you bought had a bad connection and an injector didnt fire under load, oops.



you get the point i'm sure.

Ultimate NAHeres a NA thread for him.

That's good to know, but it still leaves the question of the mysterious gook in my coolant. I don't know how old the stuff was, but I've never seen coolant look that color. But I guess if it was oil, it would have floated on top of the coolant, and not have settled out like it did.



Where's the best place to buy a jspec? I like the idea of having a spare engine just laying around for when this one blows. Oh wait, I'm only drag racing the car. It'll probably never blow. https://www.nopistons.com/forums/pub...#>/biggrin.png

That's good to know, but it still leaves the question of the mysterious gook in my coolant. I don't know how old the stuff was, but I've never seen coolant look that color. But I guess if it was oil, it would have floated on top of the coolant, and not have settled out like it did.



Where's the best place to buy a jspec? I like the idea of having a spare engine just laying around for when this one blows. Oh wait, I'm only drag racing the car. It'll probably never blow. https://www.nopistons.com/forums/pub...#>/biggrin.png [/quote]

that gook can be a couple of things. its either burned up coolant, or the waterpump seal, bits of the hoses etc. its kind of normal to see black stuff in old coolant



mike

might also be some stop leak someone put in there at some point in time

I want to go this route. After I do what's in my sig (and suspension), I'd like to eventually rebuild the engine in another s4 I have rotting away in my yard, then do a swap. What kind of price tag goes on a d.i.y. rebuild, with street port done elsewhere? I get antsy just thinking about it. I figured if I had an engine that is blow-upable (tii), I would, without a doubt, blow it up.

I want to go this route. After I do what's in my sig (and suspension), I'd like to eventually rebuild the engine in another s4 I have rotting away in my yard, then do a swap. What kind of price tag goes on a d.i.y. rebuild, with street port done elsewhere? I get antsy just thinking about it. I figured if I had an engine that is blow-upable (tii), I would, without a doubt, blow it up. [/quote]

Iit depends, if you want someplace to street port your used housings, I'm not sure who will. I believe mazdatrix wants new housings when they do porting. Check out pineapple racing, maybe judge ito can port your housings for you, there are some other web sites you can check out (rx7.com) etc... If you choose to get new housings the cost skyrockets.



It's like $900 already for just rotor kit and gasket set for a 13B from mazdatrix, that gives you all new springs and seals (apex, side, corner, oil etc) and gaskets for the rebuild. Assuming your housings, rotors, eccentric shaft, stationary gears, and bearings are all in good shape... then this would be the cost not including the street porting, presuming you are doing the rebuild yourself. There are also other costs, like supplies, hylomar, tools, cleaning solvents and tools... assembly lube.. it adds up.



In the NA motors when you port them you are basically shifting the power band into higher rpm, so it's a good idea to increase the oil pressure, get hardened stationary gears, and maybe run better apex seals with uprated springs, depending on your budget. You will probably also want to get the rotating assembly balanced. These things all effect high rpm performance and reliability. Without these additional mods you're likely to break prematurely or just not be able to take advantage of the full potential of the porting... stock apex seals start floating ~8.5k, and the stock stationary gears will start twisting past that point too.

thanks for the info...that's something to look forward to (that's not sarcasm)