revhardallday

iTrader: (1)

okay so im going to be gtting tuned soon and want to know how much psi i can run safely with stock motor.

turbo is T04z dual ball bearing
has all fuel upgrade
pfc
compression is still within specs


i was thinking 14psi

vosko

iTrader: (4)

depends how much power you want

revhardallday

iTrader: (1)

would 350 - 400 hp be to much stress on stock motor?

Howard Coleman

iTrader: (6)

here's your compressor map.



find the horizontal line at 2 pressure ratios... that's very close to 14 psi. follow the line to the right. now note the "60" on the X line. that's 60 pounds per minute of air which is 868 CFM which can produce 452 SAE rotary rwhp. and that isn't the max air at 14 psi as the rpm lines on the map are not yet in stall as indicated by they aren't yet vertical.

452 is 502 flywheel hp or 3.27 hp per cubic inch.

which means without some form of AI on pumpgas you will probably blow your motor.

i suggest you read the first post in the following thread.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/making-case-rotary-powered-fd-fix-806104/

bottom line... your turbo puts out alot of air/hp at low boost and you need AI or you will be talking to guys like me... engine builders.

good luck,

howard

sk8world

iTrader: (5)

Q or C16 with supporting mods and the correct tune. Let it rip. No reason it wont hold.

Thats what I would do...

TRWeiss1

iTrader: (20)

Were you planning on studding/pinning the motor? If not, I'd highly recommend it.

GoodfellaFD3S

iTrader: (213)

^^why? I'm making similar power to you, and have none of that. Not necessary at these power levels IMO.

OP, on 93 octane fuel I'd recommend around 1 bar/14-15 psi as a safe level to be tuned at. Basically what you stated earlier.

With AI (water and/or meth) you can bump the boost with that turbo and really get the party started, but until then.....

TRWeiss1

iTrader: (20)

Why? Simple. Because Dave @ KDR recommends studding for any application over ~425RWHP. Dave's been around rotaries enough were I trust his recommendations. I cannot make this claim because I haven't been in the rotary game long enough, but he claims that they begin twisting/tearing themselves apart over those power levels. Maybe it's not completely necessary, and I'm sure SOME people will get away without it, but I'd rather err on the side of caution. My luck's not that good.

Gorilla RE

iTrader: (1)

Oh, Dave said it? I guess I need to re do a ton of cars now...

TRWeiss1

iTrader: (20)

LOL...Like I said, it may not be completely necessary, but I don't mind the insurance.

Oh yeah, and let's try to keep in mind that Dave's been doing this for a living for 25+ years. Have you? He just *might* know what he's doing...

arghx

iTrader: (3)

you and I disagree on this point. At that level of power and airflow, you would characterize AI as basically necessary whereas I would characterize it as helpful but not necessary. On 93 octane fuel I've run FD 9.0:1 compression rotors up to 18psi (GT4088 turbo) without AI on dyno pulls (doing before-and-after AI testing) and things held together with no knock. But as the tuner you have to be less aggressive with the fuel and the timing.

On the Subarus all the fuel and timing maps are based off mass airflow per revolution. So when I tune an STi the timing curve follows the airflow and can account for everything you're cramming in there. It's trickier on an FD because there is no MAF sensor, but if tuned correctly/conservatively it won't detonate at 14psi airflow levels on a T04Z.

Islander

iTrader: (6)

On a good tune it should be ok on pump gas at 1 bar. Anything over i say take Howards advice. Ive ran a few of my cars on pump as high as 18-19psi but with lots of fuel and conservative timing.

GoodfellaFD3S

iTrader: (213)

The only time a 450 rwhp rotary will twist or tear itself apart is due to a bad tune, a bad build, or a combination of the two. I've built more than a few FD setups making power at this level, with zero studs/ extra dowels etc. It simply isn't necessary. You've got two shop owners telling you the same thing. I'd hate to see even one FD owner deal with the unnecessary expense and complexity associated with this---- there is enough of that with these cars

Dave certainly does know his way around a rotary, and is a nice guy to boot. He's entitled to his opinion..... doesn't mean his word (or anyone else's) is gospel.

rx72c

iTrader: (8)

I have done 530rwhp on a stock engine 30psi GT4202 had water injection though but it was a fresh stocker if its an old engine no matter how good compression sounds or shows I would not push it old Mazda apex seals are a real ****

bumpstart

PSI is not PSI,, different turbos have differing efficiencies
and so 18 psi on one may be 60 pounds per minute and cool
and on others it may be 48 pounds and very hot

as such i have road tuned cars with lesser turbos to 23 psi / around 400 rwhp without AI ( on 98 MON fuel )

from practical experience
1 bar boost on a t66 ( plain bearing equiv to t04z ) with 1.32 rear 3 inch exhaust and mild port
yields around 400 RWHP on dyno dynamics dynos
- no need for AI if your RON is up around 98 ( equiv to 91 MON or 93 AKI USA )
and your tune is decent

it is however near the practical limits of the fuel octane
further boost from here without AI will see the need for more drastic retard , a low AFR
and give falling returns for that extra boost

i am in agreeing with much of what is posted
( besides the need to dowel or stud )
at 14 psi/ 60 pounds per minute ,, AI isnt essential,,
,, it is however necessary to reap further gains without unnecessary risk and falling returns

as for the stud thing,, 50/50 ,, FD and s5 engines will cope,, but s4 block strength will not have any margin for error
so i am happy enough to build and tune up to 400 rwhp without need for dowel and AI
( provided i source a s5 rear plate as a minimum )

Gorilla RE

iTrader: (1)

Regardless of what "product" one is trying to "sell" you, it would be wise to take the duration of time they have been in business with a grain of sand...Not completely, but it isn't everything. Forget the fact that I am a shop owner and listen to me when I tell you, that out of all the "rotary" engine builders out there in the US, I personally would only trust 4-5 individuals to build an engine for me. And guess what? None of them are mainstream and you've probably only heard of 1-2 of them. My point is, it is easy to tell someone this shop, that shop, this guy and that guy when you only see what's right in front of you or am being told it to you. But as a shop owner, I have personally seen many many engines from every "big name" rotary shop out there... And they are usually NOT what they should be. So take from me what you want.



-J

GoodfellaFD3S

iTrader: (213)

Jonny Bruce, have you torn down any IRP engines yet? Prolly not being that you're way out on Bourbon street.

Please be gentle

MOBEONER

iTrader: (18)

I`m on stock motor aspec GT35R and water injection. I am taking my ride up to enzos and gonna max it out so see where it goes. Enzos brother was doing high 9s in a 1/4 on stock unopened motor (on E85 tho) but the motor help up just fine @ that HP.

TRWeiss1

iTrader: (20)

Don't get me wrong, I hear/respect both of your opinions. I'm not saying that ANYONE'S word is gospel, only that I've been dealing with Dave for 4 years and believe he knows his stuff. As everyone on here knows, you CONSTANTLY run into one person saying you should do it this way and another saying you should do it that way.

One thing I have noticed about Dave is that he is very conservative, and ALWAYS errs on the side of caution, which I don't at all believe is a bad thing when it comes to dealing with rotaries. I'm sure that is probably why he recommends studding...Maybe it's not 100% necessary, but again I'd rather be safe than sorry. If nothing else, it's going to add strength/rigidity to the motor, and allow for higher power levels in the future should you decide to go that route.

The bottom line is that it's an insurance policy, and definitely NOT a bad one.

MOBEONER

iTrader: (18)

maybe he suggested pinning the motor because you drag race your rotary. I my dad would pinn his 13b motors for drag..

Gorilla RE

iTrader: (1)

I understand what you are saying and can respect his/your reasoning behind it. But think about this: What if I told you that what Dave (and many others) think is "twisting" of the engine, isn't twisting at all? Instead in fact, something totally different?

I guess a can of worms would be opened ehh? The point is, there are issues with this engine that have been around from the beginning of its development that 98% of the "speciallist/rotary gurus out there have just been band-aid'n because someone else did it, told them it works or are just misunderstood. All I am saying is that just because someone has "25 years experience" doesn't mean that what they are doing is correct. It just means they could've been missing the "boat" for 25 year...

And please don't take this as me coming down on David personally either, because I am not. I am only using this situation as an example. I am also not trying to sound like I am "better than thou", forgive if I came across like that.

-J

Gorilla RE

iTrader: (1)

No, Richie-poo, I haven't. Consider your self lucky !

-J

to_slow

iTrader: (3)

So true, !!!

enzo250

You'll be surprised how far a stock motor can go. You just need to make sure everything else around it is good.. And pinning or studding at 425hp is pretty ridiculous. you can double that figure before you really even have to worry... I like your comment Gorilla RE. What people think is twist could be something completely different..

mono4lamar

iTrader: (32)

I'll agree, I just told "Richie-poo" earlier this week about the worst motor I've ever disassembled. Low and behold it's one of thee top renowned rotary rebuild companies.

Sometimes it's really tough to trust others regardless of their "credibility."