Max whp with twins
 

I'am new so be polite, I have looked around and can't seem to find a answer ..
What seems to be the most we can get of our twin turbos, I mean with what ever needs to be changed, be it the exhaust, intake, ignition, whatever... So with that in mind , Does anyone know what 's the most WHP I can possible hope for if I do eveything right with the twin turbos... Thanks..

I don't know what the max is but I just dyno'ed yestarday and I made 327 on the stock twins which was all I could do due to boost. I was only able to make about 12.5 psi or so (I think) here in Denver, Co. Elevation 5300'. When I lived in Phoenix, I was able to make more boost.

I don't know exactly how much either, but I've heard of poeple breaking 400whp. Thats with 15 or 16 lbs of boost though...and a ported motor. With a stock motor i think its around 360ish.

I think a couple of people have pushed those numbers but only to see what could be done. It's not what I would call a 'tuned' setup. Your intake temps go way up, and the turbos themselves get stupidly hot.

If you want to hit numbers over 350 on twins, get BNRs.

Dave

What does BNR stand for. I keep seeing it on the forum but never asked.

http://www.rx7store.net/product_p/bn...e%203%20fd.htm

they have them. but its funny how they want your core for almost everything engine related.:confused:

One guy over here has the UK record for 389.2hp at the wheels on stock twins :) He did blow them eventually!

15 psi is reliable and u could expect 340-370rwhp depending on your tune and wether or not u have a port. people do get 400 but thats with sacrificing reliability. that should answer ur question.

I plan on maxing out the stock set up in my FD. I'm hoping for 400WHP, I've been told it going to be hard with stock twins and SMIC. BNR are a beefed up version of the stock twins that have a great rep for low 400WHP. Talk to the guys at Gotham racing they gave me a lot of info. I was going to get them but decided it would be more of a challenge with 99spec and I wouldn't have to cut my Y-pipe. MY last dyno run was 338WHP and I've add HKS twin power and light weight flywheel since, after some tuning I'm hoping for around 350WHP.

This might help: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/finally-10s-stock-twins-non-seq-246989/

i dyno'd at 324rwhp. that was on a mustang dyno. on a dynojet it would have been around 350ish. so it depends what dyno you are on. i did that at 14.5 psi (spiking) and dropping to like 13. i started to run out of fuel pressure though.

3" turbo back exhaust
aem ems
99 twins
hks intakes
koyo rad
greddy 2 row fmic
additional injector system
stock ports
act clutch

Bryan Nickel Rotary. Great guy, very honest and knows his stuff :)!

http://www.bnrturbos.com/3rdGen.htm

Btw, if you click the dyno link in my sig you'll see a 421 rwhp run on twins.

Thanks Guys. Great info... I think i'll call Gotham thurs. .. How does everyone feel about the 99specs twins versus BNR's, Can buy either at about the same price...
But I like the idea of keeping twins versus going single... I know single would produce more power, But would like to keep it as close to original... Rich

I'm running 99 twins. At 15 PSI with a street ported motor and all the supporting fuel and flow mods, I dyno'ed ~350 RWHP. If you want longevity out of twins, I probably wouldn't recommend constant running at 15 PSI. I usually run at 10 PSI which is less than what they run from the factory at 12 PSI.

The car is fast enough at 10 PSI to get me in trouble on the street. :)

You can probably make more power more reliably using BNRs - especially with one of Gotham's awesome port jobs. Rynberg made good power on BNRs using a small street ported motor and running them sequentially.

Rich is running BNR Stage 3's not a single. that video is nuts. i like how it just jumps to max power halfway thru the pwoer band and stays rock steady all the way across.

I didn't think the 99 specs ran any more boost than the regular's did. I just thought the power increase came from primarily the Efini Y-pipe and the better efficiency of the tighter compressor housing clearances. I may be wrong though.

Actually, Rich (Goodfella) is now running a 500R single turbo now making mo' power than he did with the BNRs. He was running the BNRs setup non-seq for many years before that.

I prefer running sequential and have quicker response and more low end power with a nice broad usable power. :)

yea i miss sequential

yeah if u arwe gonna keep twins why u would run them parrallel is confusing to me. mine as well just go single. the ebenefit of twins is quick spool and low end grunt i think running them parrallel greatly reduces that benefit.

for the original poster. i would go bnrs way before going 99s in my opinion. shit i would go used set of stock twins for dirt cheap over the 99s.

This subject has been beaten to death many times, if you search you'll find lots of good info :)

I agree with what Matty says above, and if you want to stay close to original, pick up the BNR Stage 3 in sequential form, you can get them direct from BNR.

maybe i'll under my non-seq conversion...time to scrounge up all the old solenoids. I bet it would be easier to sell if it was sequential too...

In stock form, about 368rwhp is the upper limit in reliable form. Above that, the stock turbos are dying, and the temps are indeed skyrocketing like Dave said. You can destroy the turbos in fact at those boost levels (18+).

On ANY set of twins (ie upgraded), I think Rich (GoodfellaFD3S) actually holds the record to date: 421rwhp on the Stage III BNRs in parallel. And I bet ya if the manifold was redesigned, he can squeeze a bit more outta 'em too ;)

~Ramy

i would rather know who holds the documented record for stock twins (not bnr's, not 99 spec twins). but for just stock twins.

RX794 already posted the link. Check it out. John (JD) in NJ. 402 rwh-356rwt -dynoed.

~Ramy

It baffles me why there's no market for a SS OEM replacement manifold.

:scratch: that's news to me. Can anyone else confirm? that the 99 and up Rx-7
run at 12 psi.

There IS a market; it's just a LOT of complex and expensive work... Heck, you'd make more power at the SAME psi on the stockers w/ a higher flowing manifold!

Hmmm...wait a minute...sounds like something I should look info haha :D

Yes, some of the later FDs run higher than 10psi. I don't recall if it's 11 or 12, but it's a little bit extra. That's the main reason for the extra hp rating on those models.

Dave

just out of curiosity (*sp) these numbers you guys are posting.....are they on dynojet's or mustang dynos? i know the numbers on the mustang are a little lower than on dyno jet.

Here's a dyno of Rotarded's stock twins. My build is a duplicate, + a little this and a little that. The tuning is being finished this week. I will have it on the rollers soon and post the results.
http://i99.photobucket.com/albums/l2...withnoname.jpg

If i had the money for it i would already have a product on the market! how about a flange for an external wastegate?

thanks for clearing that up Dave.

I sincerely doubt the new ebay-oriented ownership is going to drop the $700 or $800 (or more) for a custom SS manifold for the twins. The stockers cannot boost high enough for the stock manifold to really be a restriction anyway.

Cold hard truth: I can count the people on this board that have "reliably" run more than 350rwhp on stock twins using less than two hands. If you are wanting to run 350+ rwhp, ditch the stock twins and go with the BNRs or go single.

which is a syndrome due to the new "ebay oreiented" ownership u speak off.

Not necessarily. I think you and a few others have been a bit lucky with turbo longevity. I think everyone here knows that I don't shortcut on maintenance or on anything with my FD. Yet my stock twins were complete toast at 85k miles, about 65-70k of which had been run at 10 psi. I've seen a LOT of people melt twins running 14+ psi, no matter how they maintained the car. This isn't a dig on the stock turbos so much, they just weren't designed to run at those boost levels.

I'm hoping that the better CHRAs in the BNRs will last a very long time at 15 psi. If not, they were still cheaper than brand new stock turbos. :)

honestly..its probably a combination of both. luck and these new idiots that buy our cars. sorry i am less pc than u.

So let me ask this. BNR3's are $2995 and can get you to the 350-400+ mark with some reliability. But, if you make the stockers hit that mark and get, let's say 10,000 miles out of them. Wouldn't it be easy to justify just picking up another set of stock twins for $200 off this board? Proper tuning and care for the motor put aside. If it's just blown stockers that need replaced, that's just a little time under the car.

Your thoughts?

1. They are $2350, not $3k
2. They make more power than stockers, especially above 12-13 psi. The vast majority of people never see more than 350 on stockers, especially those of us on 91 octane.
3. They run cooler than the stockers.
4. I would rather pay the money and not have to keep R&R turbos.

The most I have seen on BNR 3's is 427whp. Has anyone seen higher?

Even at $2350. that's still some cash to put out of pocket. Might as well go single,IMO.

I know they are more efficient and run cooler. But, How long is the life on BNR3's at the 400+ mark?

Rynberg, I know we are in area's with different car needs, wants, and driver desire. My point of view is from a car that is not a daily driver and is stored for 4 months a year. That reduces the wear factor and miles. To me, I can justify swapping turbos once a year. Whereas, if it was my only car, I can see wherer this would be more frustrating.

Just a couple of thoughts:

I made a solid 350 rwhp at 12 psi on a dynojet with my BNRs.

The turbos should last quite a long time at 400 rwhp, which on my setup was about 15.5 psi. The turbos can run 19 psi all day long, so they aren't very stressed at the 400 rwhp level----as mentioned, the bottleneck in the system is the manifold and not the turbos themselves.

Re: swapping out turbos every year, along with the extreme pita that that entails wrt to time and labor, you're also looking at spending on all the gaskets, studs, and nuts to do it right (and they aren't cheap), along with the fact that at this point used stock twins are almost all garbage----damaged turbine wheel damage from a blown apex seal adventure, bad seals leading to excessive oil smoke out the exhaust and/or into the intake. No thanks.

coming from a guy that is on the fence about going single vs BNRs:

1) worn out stock turbos suck. If you have to rebuild them might as well throw them away.

2) what are you looking out of your setup. What's the target HP range. Quick spool or high HP.

BNRs in sequential form will out response a BB single that's for sure. BNR's wont a outflow a single.

3) smog laws

4) supporting mods that you already have vs those that you need for the single. Example that DP you has to go. Can you keep that SMIC? choose manifold carefully then. 4 inch full exhaust works best for singles.

5) @2350 the price is stil lower than new stockers.


I think I'm gonna end up with simplified sequencial BNR's as my HP goal is < 400 RWHP and quick spool is a must.

There are pros and cons to every choice. BNRs are great for people who live in smog-nazi states like Cali and for people that still want the feel of the sequential twins. If neither of those things applies to you, AND you can afford a proper single conversion (a lot more than $2350), then yes you should go single.

I personally think you are nuts for wanting to put up with R&R used turbos, but it's your time and lower back. My car isn't a DD and in fact, hasn't been driven in 6 months. But my time is still my time and I sure as hell wouldn't want to do it.

The manifold as a flow restriction? Well maybe not.... I've been investigating this "manifold" question and potential mods. I've adapted the manifold to a flow bench and was quite surprised by the results. The research seems to implicate the turbines and not the manifold.

As it turns out, the manifold isn't really a restriction at all (in secondary mode, with both turbos operating) and the effect from the presence of the flapper valve is negligible. There is, however, restriction when operating in the "primary" mode and flow is not balanced front to rear.

And while not necessarily a flow restriction, the manifold is not a flow enhancer either. Any benefit from a redesigned aftermarket manifold would probably come from the dynamic effect of extending the port (i.e., tuning effects, column inertia, constant cross-section, port isolation, etc.).

The benefits of having the short cast iron manifold, however, include compactness, improved initial turbo response and the long life span of a stable material.

So it seems that culprit is the turbine housings. I know this will not surprise some of you, but as of now I have quantitative data to support that assertion. They are very, very restrictive. Anything that can be done to improve their efficiency will improve flow and power. And there seems to be room to do so before the stock manifold is maxed out. Surprise!

I suppose I should have said 'turbine manifold' or 'shared turbine housing.'

Rich, I liked your BNR set up a lot. And to be honest, that is what I have based most of my BNR info off of. You made, what I thought was, great power.

What I'm looking at/testing is to see what kind of life I can get out of these and what power levels. I'm not looking for big HP. However, anything close to 400WHP on stock twins should be considered huge, IMO. Big HP should go big single. What I'm looking for is the medium range with fun, and not a big expense. This may change later, but it's where I am now. With the people who have helped me, we know that 400 + can happen and be run at that level for several thousand mile. No engine damage occurred, the turbo's did not blow. That person who made 402WHP decided to test the gt28's to see about more power. They were not pleased with them. They then went to a gt35r and to this day, states the twin set up was by far the more reliable and fun. The car was totaled by someone hitting him at an intersection. And now he has gotten out of things for awhile.
I say all of this to show that this may be something that works out. It may not be for everyone. But, it is an option to make people aware of. I will not claim to know all the exacts of the build. I have had A LOT of help with it. But, I will say if you are blowing apex seals with this set up, I have to think there was a contributing flaw in the build, or tune. Blowing / over working the stockers and having to replace them is less than 2 hours for me doing it alone on my set up. I had had them off to check things several times early in the build. Accessories aren't that big of an expense that I have run into. And I have no problem working with used, good condition turbos. I know it's not for everyone. I personally hate popping on and off the clutch ring. But, I will mess with turbo stuff and not mind. I know it's a pita for many people.

It's all preference. I don't want to steer anyone down a road that is going to cost them more money. We are doing this to see what it can do and keep the FUN in driving the car. The car is with the tuner and he has been detailing the tune over a few days as he can spend time with it. I will document things and post the details of what we have and see where this goes.

I do understand all the points being made. I like the info being shared. And I hope this is not coming across in a argumentative way. Thanks

That's cool man, different stroke for different folks :). Let us know how your project works out, and it was nice meeting you out at Deal's Gap this year :icon_tup:

I just wanted to chime in and remind everyone that our turbos are actually LARGER than the Supra turbos, but the manifold and runners are MUCH better designed on the Supra turbos than ours. That's why they've made 500rwhp on Supra turbos (not very reliably, but it's been done lol), but we've barely touched the 400rwhp on larger turbos on the FD.

~Ramy

Rich, it was great meeting you too. I hope to post the results soon.

Ramy, that's good info. Thanks

Which portions of the Supra manifold and/or runners are you referring to? The exhaust manifold or the turbines' exit?

why are the 99spec turbos more expensive than the BNR stg 3?

That's like asking why is a Mazda oem strut bar $750 and an aftermarket one $100. Brand new oem parts vs installing larger Garrett CHRAs into existing core set of turbos (not that they just bolt right in or anything but you get my drift).