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Max power from sequential system
I know this question has been asked many, many times, but technology keeps changing and the bar keeps going up. :nod:
What's the most power you can reliably make from a sequential setup on pump gas? What is the emissions effect from this tuning? |
I'm wondering as well, going to get a tune this spring, hopefully 14psi on stock seq twins.
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they are mechanically limited by their weak centers. Tuning won't help when they snap the to small shaft. Thats not to say you can't do it, tom did it for a little bit till he lost his engine. look in the time slip section for a thread about running a ten on stock turbos.
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Originally Posted by HiWire
(Post 11642723)
I know this question has been asked many, many times, but technology keeps changing and the bar keeps going up. :nod:
What's the most power you can reliably make from a sequential setup on pump gas? What is the emissions effect from this tuning? When talking about reliability, the issue has always been and still is governed by turbo longetivity. No amount of technology can change that. That is of course you change out the stock turbos :p: For reliability purposes, most would agree that the threshold is 15 psi for stock turbos. Some would argue that its more. Depending on your setup, tune, ect 15 psi can yield you 330-350RWHP on the average. |
Since you mentioned a sequential setup, don't forget you can upgrade the stockers to Stage 3 BNR turbos that are stronger than the stockers. It seems every year there is a group buy for them.
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^^ very true. With that said check this out
Originally Posted by Mr rx-7 tt
(Post 11640240)
https://www.rx7club.com/attachments/...-2012-dyno-jpg
We made 433 rwhp @ 18 psi with BNR stage III's. We now run 20 psi so I'm sure we are making right at 460 wheel horsepower. New Porsche twin turbo saw the rear end recently... |
430 hp / 322 ft-lbs on a sequential setup is pretty damn impressive.
My FD was quoted at "320 hp" by the dealer, so it looks like it was tuned pretty close to the max for stock turbos, with a little safety margin (previous owner was a time attack champion). |
^^ how much boost are you running?
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330-350 is realistic for stock sequentials around 14-15lbs.
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Originally Posted by HiWire
(Post 11642917)
430 hp / 322 ft-lbs on a sequential setup is pretty damn impressive.
My FD was quoted at "320 hp" by the dealer, so it looks like it was tuned pretty close to the max for stock turbos, with a little safety margin (previous owner was a time attack champion). if thats how it is I think you should give it a try and keep the car like that instead use the money for track time and enjoy ! |
That's what I've been doing. 320 is enough for me... I haven't even fully used it on the track (the Greddy boost controller is set on "low boost" - which might be about stock power). Also, I think the tuner was going for power across the band, not just max hp.
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Originally Posted by HiWire
(Post 11642932)
That's what I've been doing. 320 is enough for me... I haven't even fully used it on the track (the Greddy boost controller is set on "low boost" - which might be about stock power). Also, I think the tuner was going for power across the band, not just max hp.
VS high boost ? |
Dunno. I'll see if I can find out.
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HiWire, get a dyno done. lol
thewird |
Just dyno'd 296 HP on 99 specs at 14psi
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Congrats. Are you happy with the power?
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Originally Posted by Tripple 7's
(Post 11643976)
Just dyno'd 296 HP on 99 specs at 14psi
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Originally Posted by Tripple 7's
(Post 11643976)
Just dyno'd 296 HP on 99 specs at 14psi
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I had to run about 18-19 peak psi on the stock sequential twins to make 342 on the dyno with pump gas and my first couple years of tuning, and when I turned the boost down the power dropped off significantly. But I was able to run low 11s at 123.80 mph, all the info is here https://www.rx7club.com/time-slips-d...-video-702888/
I went through about 4 sets of stock turbos over the years, most of the time it was when it was non sequential and they just developed too much shaft play and some leaked oil. Only broke one turbo shaft at the impeller nut on the last set, right after I removed one stock blow off valve and my greedy bov was adjusted too tight and not opening very far. I blew the original motor and then another motor with single turbo and 528 hp when it leaned out way too much. |
Originally Posted by Mahjik
(Post 11644791)
You either have a problem with your car, or a problem with the dyno.
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I made similar power when I turned the boost down to 15-16 psi, I forget the numbers but they should be in my thread. Maybe it's the dyno, or the car tuned too rich which makes a big difference.
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Originally Posted by Tripple 7's
(Post 11643976)
Just dyno'd 296 HP on 99 specs at 14psi
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Without knowing what dyno was used....and gotta love these comparisons with the barest detail, I'd say that is a typical DD twins figure or maybe just a touch low on 1 bar boost - unopened engine.
Problem with the dyno - perhaps more realistic maybe? |
Here is a quote from me in one of my other threads https://www.rx7club.com/time-slips-d...-motor-807341/ when my car only made 313 HP with 16.7 peak boost, but then it made 368 HP when I turned the boost up to 21 psi peak.
Originally Posted by tom94RX-7
(Post 8806614)
I just had my car on a dynojet again, this time it was with full non-sequential stock turbos. 368.88 RWHP, 335 torque, and max boost was 21.7 psi on the greddy profec b-spec 2 boost controller. When it hits full boost it goes up to 21 psi, then it drops down to 19 psi and holds steady all the way to redline, it actually starts creeping back up to 20 psi at the redline. Dyno sheets will be uploaded in the next post. When you look at the dyno sheet, you can see max hp is at 6k rpms, this is probably the rpm when boosting 21 psi, then you can see the hp drops down as the boost dropped down to 19 psi.
I also did the first dyno pull at my low boost setting, it peaked at 16.7 psi and it probably held at 15-16 psi since it always peaks higher than it holds after it peaks (I was watching the AFRs not the boost gauge). It only made 313 HP! This all proves to people who say that these turbos don't make any more power above 15 psi, they really can make much more power above 15 psi! 55 HP is a big difference. And to add to that, my 2nd pull I made 362 HP, I turned up the boost a very small amount (from 67 to 69 on the boost controller) and made 368 HP on the 3rd pull. My other thread is "342 hp dyno & 11.19 @ 123.80 video", that was when my car was on the dyno and only hit 19 psi on the dyno and its only been holding 17 psi boost at the track running 11.16 ET, I just found and fixed two big boost leaks from both bad gaskets in the turbo ypipe. |
That graph showing 430+ is on BNR stange 3 turbos.
Sequential turbos running 15psi with all other supporting mods should net you 350whp. As others have said, they higher the boost the faster you're going to eat turbo's. The only solution is to go single turbo or go to BNR stage 3's. |
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