new fd tear down
 

I bought a fd in decent condition over the winter and it is going threw a full tear down to the bear metal. The car will be rebuilt with new motor (the old one is good but if I am going to do this I rather do it once) large streetport (never did a rotary before but a lot of chevy and ford big and small blocks) all the reliability mods will be done. Haltech computer, bigger injectors, I think racing beats duel tip exhaust with down pipe hi flow cat. v-mount intercooler. Every thing done right but this is my first import and first turbo and the turbo part is my main question I want a low end grunt being a old fashion displacement kid. I want 400 RWHP on 15lbs and 350 on 10 lbs. but most of all i don't want the lag/spool up time (ceramic bearings, variable veins, ect?). Money isn't a big concern sold my 73 mustang not to long ago. I have looked at a lot of this site and can't get enough to push me one way or another on the turbo debate. please help me threw this decision. hear is what i am starting with.

here are pics

That's "decent condition"? :scratch:

You're not going to have low end grunt with any rotary motor, let alone a street-ported single turbo (stock sequential twins on stock ports will give you the best low end). Almost any single turbo can hit 400 rwhp at 15 psi -- you should look into a GT35R/T4 setup from A-Spec (forum vendor).

Lots of info on the site, please read the FAQ threads and use the search function.

Looks decent to me.

Anyway, if you want low-end grunt, that pretty much says sequentials. No other turbo setup will give you low end without dying badly at the high end, and I think we all agree that's totally unacceptable. If you want a lot of low-end grunt, then BNR Stage 3 sequentials should do it best. The complexity of the sequential rats nest isn't terrible if you have removed the emissions components.

Normally a project like yours screams single turbo, but if you aren't willing to give up some low end, then a single simply can't cover the RPM range of a rotary.

Dave

umm...look at the roof behind the sunroof.

You're going to need a whole new roof, hope you have an excellent body shop doing the work. If I may ask, how much did you pay for that car? And how did the damage happen?

Anywho, to your question. As was stated above, you're not going to get the low-end grunt of a small block, let alone a big block, with any rotary. There just isn't enough displacement. To come close, as was stated in the post that I quoted, the best way to pull off your goals is to go with the BNR Stage 3 twins, sequentially setup. Rich (GoodfellasFD3S) got just over 400rwhp in the mid-to-upper-teens of boost (don't remember exactly what PSI it was at), but he was running non-sequential. Running non-sequential, you're looking mid-to-upper 3k range for full boost. Get yourself Stage 3's setup for sequential operation, get a viton hose kit and viton check valves, and get ready for a little bit of a headache putting the rats nest together.

Oh, yeah. It helps when they keep the rubber side down.

Thanks for the advice I had not seen the upgrade twins this looks like more my style then a big single going for peak HP were I want more usable. the dent in the roof is almost taken care of a lot of heat and hammer I have done a tone of classic cars 32 coup steel body ect. were bondo is not ok. The dent i was told was from a tree limb after a wind storm that put a dent in the roof and rear quarter. The kid that had it did not have the money to fix it so i picked it up real cheep.
Thanks guys this is my first real post and it has been a good experience

haha I want to see pictures of what you did with said heat and hammer.

demkog: to give you an idea with BNR Stage 3 sequential and streetport, here's my dyno sheet at 13.5 psi with a little bit of ignition breakup:

https://www.rx7club.com/showpost.php...52&postcount=9

welcome to the rotary club!

in my prior life i was a ford guy. i had a 1965 gt350 shelby mustang in 66 and a Boss 302 in 69.

i switched from racing fords to mazdas in 83 (GT3 SCCA). i traded street cars when i switched racecars and bought a new 83 rx7. i have never driven anything but mazdas since...

if you do it right your rx7 will blow you away and the difference between a reliable very fast mazda and a train wreck is NOT dollars rather it is picking the right mods. there are many landmines so i urge to to do research before you pull the trigger.

i suggest you forget the low end grunt concept.

the rx7 is 500 pounds lighter than your mustang and it has less front weight %. my middle range turbo suggestion (GT3574 from A spec) will do around 420 rwhp and at 2800 pounds you will need to be careful in the first 3 gears not to go sideways. so even though the torque might not be similar depending on car v car mods you will be smiling.

there are alot of single turbo options today that spool up right now. they really clean up the engine compartment which stock is a clutter and thermal disaster.

the OEM turbosystem manifold is cast iron, weighs 22 pounds and is bolted to the block. there is almost no material more heat retentive than cast iron. it gets real hot w the rotaries 2-300 degree hotter egts and then just cooks the poor old aluminum rotor housings. a single turbo substitutes 6 pounds of stainless steel for the 22 pounds of cast iron and allows cooling air all around the hot side of the motor.

before you consider any tricked out version of the OEM system spend a half an hour looking at the cast iron OEM manifold. compare it to a single manifold.

everything you need to know is right here on this forum. everything.

give us a better idea as to what you want to do w the car and you will get lots of help.

good luck,

howard coleman

Looking for a hatch? I have one for sale, i don't mind delivering it to you either! Let me know...

Since you are a chevy guy....have you thought about putting an lsx motor?

The reason i got the rx7 is to play with the wankle and if i am going to keep up with the times to learn how the whole turbo seen works. I love the old pushrod chevy v8 and will never stop playing with them but i want to at least know what the import seen is and no better way to get to know it then building its king car.

I am happy to hear you say this. I too love the chevy motors and they are so much fun. But the wankle I must admit I like even more. So much potential in such a small lil motor. quite amazing.. Good luck with this project, it sounds like this FD got a great new owner. Just like Howard said, everything you need to know is pretty much here, it is just a matter of finding it. Do LOTS of research before making a final decision on a modification. Again welcome and good luck!!

Thanks for the support, love the stunter bike, just sold my Yamaha FZR and in the process of buying a bulle fierbolt. But back to the turbos I do think the twins are the closest to what I want and I know the low end grunt of 7 litters is not what the wankle is all about but insane RPM. but what is the quickest spooling single for the rx7 in order to get that relative low end coming in as soon as possible while still finding 400 rwhp at the top because from what I have read here it is the easier way to go and as above stated heat management is better. sorry if I am speaking out my ass here by asking for that witch I don't think I am pleas tell me so I don't clutter this good forum. If any ignorance is from lack of experience But I have learned all the text book (flow maps, trims ect.) stuff but lack the hands on in this case and nothing beats actually trying stuff out.

I have a good roof off a parts car I could sell you. If you have the money go with the 35R and get it over with. You will not be dissapointed with the spool time/power.

No need to kiss ass; you're in the club already. :)

I think you'll be thoroughly happy. As for the turbo choice, very few have regretting the single turbo switch. The simplicity, reliability, and lower underhood temps outweigh the relative lack of down-low punch.

In case you weren't aware, na rotary motors always make a flat torque curve on the dyno. So your max horsepower for a rotary na is at the very top of the RPM range. Even if you add a turbo, your real powerband is the upper half of the RPM range. The sequential turbo setup was chosen mostly to make street driving more exciting, and give the non-performance driver some excitement without having to downshift. Sequentials do push up the torque and power on the lower half of the rpm range, but still it's pretty lame at/below 3k. Except for street driving and autocrossing, there aren't many applications where the sequentials are well suited.

Dave

Save yourself the expense of the BNR's and just go single. If done properly there is not that much difference in spool time (500-800 rpm).

Nothing is more frustrating as when the first turbo comes at WOT and the second doesn't.

If you don't want the BB turbo the 3574 from A-spec is very good, and cheaper than the BB unit by 300.

As Ihor and myself suggested, a GT35R/T4 kit would match your needs very well and is a killer single turbo for the FD.

This thread should be a lesson to all newbies:

You get good help and aren't ridiculed if your first post reads as if you actually put some thought into it.

Woe unto those who type while wearing the sideways visor of retardation.

Welcome to the club. Definately the GT35R will be your best bet. When I go single I want to go with the A-Spec 500R. They use the GT35R in that setup.

LOL :rlaugh: :crackup: