Alexander Startsev

I m still at my custom build i started last summer, unfortunate events delayed project but now it s getting together. I m doing some street tune and it looks like I ll be getting in 15 psi range around 4.5-4.8k on 4th and 4k on 6th, with spool time on 6th at 5k about 1sec, maybe slightly faster (on lower gears quicker because it gains rpm fast).
Is it good? is it bad? Is it average?
Can definitely feel lag at anything below 5-5.5k...
Thing is I m running 7670 but I abandoned idea to go anywhere near 600hp original target and now looking at 450-500 range for which 7670 is sort of on the large side.
Maybe I should go 7163, i ve heard it spools crazy fast, 500-1000 rpm earlier than 7670 depending on circumstances.
What fo you guys think?

spdracerut

Yes, without a doubt, do the 7163. It makes nearly the same power as the 7670 but it will spool up much faster. They use different turbine wheel designs and the turbine wheel on the on 7163 is much more efficient which allows the 7163 to make similar power to the 7670.

Alexander Startsev

Won't T25 be a limiter factor for 500 hp? I m now T3 and can't go T4 TS, only T25 SS.

ninetysixyenko

How fast do you want the turbo to build boost? my 7670 is at 15+ PSI at 4,000 without any sort of anti-lag type of tuning. I had to keep my VTEC engagement high (4800) to avoid low end boost spikes, we were originally getting 20+ PSI spikes as early as ~3000 when we had VTEC engagement that low. If I am rolling in 4th or 5th at 4,000+ and nail it, it's literally almost instantaneous, I've surprised a few local kraftwerks guys. I have a very long & wide runner custom manifold as well, so I would expect mine to be "laggier" than most EFR setups.

Also, where are you for power currently? I've been contemplating upgrading to the 8374 due to the 7670 running out of breath above 8,000. I'm sitting right at ~500WHP, but I don't think I'd be able to squeeze any more out of it without going e85 or getting a 8374. I start to get pretty severe boost droop right around 7,500. I couldn't imagine stepping down to a 7163.

Alexander Startsev

20psi @ 3000 am I reading it right? I've been to "power chart" thread and haven't seen nothing spooling past 10 before 4k. That of cause applies to normal dyno/4th gear run, if I run it on 6th it will spool before that but who gonna sit at 6th for the sake of "early" spool?

Alexander Startsev

Also what egt do you run?

ninetysixyenko

Yes, you read that right, but they were spikes, they didn't last more than ~300 RPM. The small Internal Waste Gate couldn't act fast enough with VTEC engagement that low and a quick spooling turbo and was undesirable and we worked around it. The point being there was that you can make the 7670 spool plenty fast enough.

No EGT, I don't run an EGT sensor, it's about the only sensor I don't have.

Alexander Startsev

I asked for EGT because it seems to be the only way for me to get it spooling faster, but I'm at 1650 and I don't think I'm supposed to go any further.
I'm only tuning my car and occasionally running 12-13 psi, power satisfies, I'll do 15 and maybe a bit more but only a bit. My target is 0-100 in 10 s.

ninetysixyenko

I can't help with the EGT, but I can tell you I am at 10.9-11.1 AFR and I believe 12* of timing. It ramps up to 14* once I'm on high cam. I will try to double check the timing tomorrow.
Are you using the BorgWarner Wastegate actuator or a Turbosmart/Forge? Are you using the boost controller?

Alexander Startsev

11 afr sounds conservative I was trying to adjust it anywhere from that to 13.5 and spool is definitely fastest at 13.5 (I'm not keeping that...)
I'm using standard BW canister.
Tried plugging to intake mani/turbo outlet/through boost controller - doesn't make any significant difference in spool time, only max boost. I even tried to block it completely (watched closely on boost to disengage throttle once boost hit 15) - same result: it spools to 12-15 at 5k on 3rd, 4.5k on 4th and 3.8k at 6th.

My header is small volume, tubular type but not equal length.