Trevor

Is my 339.9 RWHP towards the top of what's possible on sequential 93-95 turbos?

http://members.***.net/trevorlj/trevdyno.gif

Who's made more? Was the motor ported?

Trying to figure out if I have more left on the table while staying sequential...
11.3:1 AFR
12.5 degrees leading timing at 5000 (torque peak)
17.5 degrees leading timing at 6600 (HP peak)
24 degrees of leading timing at 8000
8 degrees of split while in boost

It's gone 114.5 mph on a different pass than my 12.81.

I think backpressure is doing me in.

dubulup

thats a monster of a car...400hp seq FD with over 260ft-lbs under 3.5k rpms!

IIRC, you are running some alky?

sad to say, it looks like your primary turbo runs out of breath @ 3.5 also...can you switch the transistion to sooner??

does your boost tapper off after 5.5k? thats a serious constant torque drop.

since you're making MAX hp at 6.5, I'd say you are about tapped out, unless your have some restrictions you can remove. Looks like you are running the twins out of their eff. range. How much boost?


AWESOME looking power band up to 6.5k!!!



I believe Tim Benton made more seq, but with 99 twins

GoodfellaFD3S

iTrader: (213)

Generally speaking, you won't reliably make much more than you are for any period of time.

FLA94FD

From what my tuner has said 340-360 is pretty easy at 14psi. Porting would make a difference. Running 14psi on the street with good turbo habits shouldn't take much life out of them.

G's 3rd Gen

iTrader: (11)

I am making 370 rwhp @ 15 psi stock twins non-seq. though. It pretty common w/ a good port job. My afr's are 11.1 or less. Obvoiusly its not good for the turbos but as a weekend car its no problem. Used stock turbos are a dime a dozen anyway. I will eventually go bnr's when they are proven to be reliable enough to spend the $$. G

dubulup

I disagree about this being easy (seq.)



again...we are talking seq in this thread.

Trevor

Yep...I'm running denatured alcohol injection to keep the charge air temps and knock in check.

Transition - I've already dropped it 200 rpm since the dyno (that transition was ?4080? Whatever the stock PowerFC base map is set at). I want to go back to the dyno, delay transition til like 5k, and record a pull to 5k. Then change transition to like 1k and do a pull in "non-sequential" mode. Take both pulls and overlap them in the Dynojet software to figure out where to put the transition for good. Right now it pulls OK on the primary but what do you expect...its a little motor at 3500. Once it transitions the car boogies pretty well.

Boost was 15-13-15 on that pull holding to redline. I think the power drop off is the lack of flow thru the turbines at high RPM. I've run up to 16.5 but the gain is barley noticeable...probably less than 8 RWHP.

I'm in no hurry to kill the stockers but once they go I'll have a reason to get a GT35R past the wife!

Don't get me wrong with me posting this...I'm not unhappy with the results. I wanted to make this thing hang with a stock 04 Z06 on stock sequential turbos and I'm pretty happy to have met my goal.

G's 3rd Gen

iTrader: (11)

I know.. Seq. is not worth the headache above 12psi anyway. That is the main reason I switched..G

njstreetrx7

Jd Made 405-410 With Stock Turbos/stock Motor And Crazy Tuning1111

Trevor

Were talking about 93-95 stock turbos in sequential operation only. JD only went 115 mph when he was sequential. After he went non-sequential is when he put down 402 RWHP and went 121.7 mph

turbojeff

iTrader: (30)

I agree.

Max HP isn't the same as a decent turbo life. Run stock turbos at 15-16+psi and they won't last a long time.

Trevor

Hmmm...snooping around and it seems 114-115 mph traps is about the limit on stock sequentials and a stock port motor. Brooks Weisblat nailed 362.5 RWHP and 120.35 mph on sequentials but he was on a ported motor. There were also 3 other people running 116.8-118.0 on stock sequential twins but after digging they were all ported too (some had ported wastegates too).

I guess I'm not doing too bad after all.

tcb100

Trevor I ran an 11.69 sequential, with a cat, but on a ported motor. I think the last time I had it dynoed I was around 335 or so. I just don't remember.

And as of today, on the dyno, one of my turbos started leaking oil pretty badly.

I am, almost as we type, trying to get a GT35RS past the wife.

Wargasm

From what I've seen doing dyno runs... when you get up to about 13 PSI or so... the stock twins are starting to max out up top. Yeah, 2 or 3 more PSI will pick you up a little power, but it's not much. The thing you probably WILL see is that 2 or 3 more PSI at say 4000 RPM will make your torque numbers and midrange go up a nice bump... but you're paying for that up top when you overheat that intake air and blow your motor later on.

IMO, stock twins + full mods (full exhaust, ic, ported engine, etc) shouldn't really be run over 13-14 psi. The overal airflow provided by "full mods" is just too much.

If you have a mildly modded car, it seems you can actually get away with a tiny bit more boost, but that's because the overall airflow is actually still lower than with a more modded car running lower boost.

adamtassell

Does anyone know the answer to the above question, but for the 99 and newer spec turbos? How much more power are they able to make? Are they able to run higher safe boost levels?

DaiOni

the vast majority of japanese tuners run their twin turbo FDs @ .9bar (13psi) - 99spec or earlier versions. I'm pretty sure they've worked something out about the setup...

cloead

My best trap on stock twins seq was 117mph.

Trevor

Really? Because I see you got your FD a year ago, went 112.8 in April, Put down 298.1 RWHP in Jun, Went 109.1 in October, then you wrecked it three weeks ago.

Kinda strange...you're rather active on the board. Why didn't you post up something that significant?

Matt Hey

The '99 spec twins are more efficient and responsive (spool faster) but supposedly are not as reliable as the older twins at high boost. It sounds kind of odd considering the '99 spec are run at about 12 psi instead of 10 psi but that's the rumor. Look at the BNR's or upgraded earlier twins for max power and higher boost levels with sequential.

The pressure drop of the IC is more important with stock style twins because the boost can't just be turned up more as with a single turbo. The exhaust restriction needs to be low especially with no porting in order to have any kind of high end as the stock turbos and engine are both running out of breath around 6000 RPM where the higher boost is making the most difference.

dubulup

haha OWNED!!

Boostn7

Honestly, don't remember my best with the seq twins but I did notice after ~15psi boost control with the seq system became an issue. Since the motor is making more power and revving faster the solenoids and actuators don't operate fast enough too keep the transition smooth like stock (9.5psi). Loading the engine @ different rpms would give different results and when boost was lowered things worked normal !!!

This is the main reason I went to Non-seq.....which gives me one smooth curve which I could depend on.

402rwh and 122mph was the best on a non-seq twins and stock motor.
125mph was the best on ported motor and non-seq turbos.

After 17-18psi the huge restriction is on the exhaust side.

Hope this helps...
JD

Rxmfn7

iTrader: (4)

If I may just ask a quick question.. I dont really understand why you can make more power non-seqentially, than with the stock sequential operation. After transition, basically everything is the same on both modes, correct? Is it just a problem with transition control, or what? I know Im not making huge power, but I can hold a steady 14psi till redline with only a ~2psi drop in boost at transition running an old ProfecB controller. Im just trying to decide whether or not to stay sequential when I get my BNRs.

rynberg

THEORETICALLY, you should make slightly more power due to less restrictions in the exhaust path (with full non-sequential, not poor-man's). However, AFAIK, no one has been able to demonstrate any significant gains.

The problems with running high boost sequentially are twofold:

1. Under high boost, the turbo control system is hard-pressed to operate properly (as Boostn7 pointed out above).

2. The secondary turbo must be overspooled to come online with minimal transition dip. This is incredible stress on the secondary at higher boost levels.

I am hoping that the CHRAs in the BNR Stage 3s can handle this extra stress over time as I plan on running 15-16 psi sequentially once tuned in a few weeks. The other question will remain to be answered -- can my recently rejuvenated turbo control system handle the high boost sequentially. We'll see.

cloead

Because I didn't feel like it? My best trap was 117, I didn't have traction obviously. My best time was 12.3@115 with a 2.0 60'. And trapping 117 isn't really "significant" by any means. I was just pissed I couldn't break into the 11's. And I've been to the track about 10 times and dyno'ed my car about 5 or 6 times.. I didn't make posts every time, there's not really a reason to..

????

Trevor

Trapping 117 mph on stock sequential twins and a stock port isn't significant? I'd say it is....especially considering you're the only person on this board claiming to have achieved it.

As of Oct 1st you had went 12.76@109.1:
https://www.rx7club.com/forum/showthread.php?t=468271
In the same post you stated your best from a previous track visit was 112-113 mph...sounds possible to me.
Oct 3rd - A little over 300RWHP
https://www.rx7club.com/forum/showthread.php?t=468664
Oct 15th - Your turbos were crapping out:
https://www.rx7club.com/forum/showthread.php?t=472184
Oct 22nd - You had added an HKS Twinpower but still hadn't tuned the car (9.8:1 AFR's):
https://www.rx7club.com/forum/showthread.php?t=474632
Nov 3rd - Your car=RIP

So sometime between the 3rd of Oct and the 3rd of November you went from 109 mph & "a little over 300 rwhp" to running 117 mph with the only change being an HKS Twinpower? That's a hell of an ignition unit there...I wish mine gave me that much power.

I'm sure you can understand my skepticism. It doesn't take a slide rule to figure out things aren't quite adding up.