View Full Version : Tomei SR7960 Overboosting?
Engmus
04-15-2018, 06:19 PM
Looking for some help.
91 240sx
SR20det
Yellow STi 550 cc injectors
Z32 maf
RSenthalpy tune
Powermaxx downpipe
Isr blast pipes (temporary)
Aem boost gauge
Walbro 255lph pump
300zx fuel filter etc.
Under full acceleration the boost gauge is saying 20 to 24 psi and I have the plumbing of vacuum directly into wastegate actuator on the tomei.
I did not adjust the actuator myself.
I can get pictures of anything requested but all I can think to do at this time is pull my exhaust side and go externally gated. Unless someone else knows something that I'm missing.
Much appreciated I don't want to boost spike my sr20 into a scrap bin
e30gangsta
04-15-2018, 07:14 PM
Happens with that setup. Weld the flapper and go external gate setup so you don't have to deal with boost creep anymore.
Was your target psi 20? Is there a mbc or anything else on your setup? Are you getting the signal from the hotpipe?
Jtuned_andy
04-15-2018, 08:03 PM
People complain of boost creep on Tomei units but apparently if you radius the wastegate hole larger a few MM like DSM guys do, you can possibly minimize this problem.
Engmus
04-16-2018, 05:59 AM
Happens with that setup. Weld the flapper and go external gate setup so you don't have to deal with boost creep anymore.
Was your target psi 20? Is there a mbc or anything else on your setup? Are you getting the signal from the hotpipe?
Target was 17-18 PSI, the longblock is stock, and I think with that setup i'd be at a solid 300 whp happy all day.
Edit: Signal is coming off the FPR line. Something like this from memory and not looking at the car.
(FPR to T-Splitter, T-Split runs to Manifold port near Throttle body and Boost Gauge line)
I have a Hallman MBC, but its currently disconnected as I tried to sort out the overboost issues.
Engmus
04-16-2018, 06:00 AM
People complain of boost creep on Tomei units but apparently if you radius the wastegate hole larger a few MM like DSM guys do, you can possibly minimize this problem.
Ugh lame, i'll probably just save the coin and go External at that point.
Thanks
koukimonst3r
04-16-2018, 06:18 AM
Had this same issue, got rid of my internal and went external wastegate. Never had a problem since.
Engmus
04-16-2018, 06:41 AM
Had this same issue, got rid of my internal and went external wastegate. Never had a problem since.
Thanks, thats lame.
What external did you opt for?
Psychomoongoose
04-16-2018, 10:31 AM
TIAL MV-S on an OEM manifold is a great option, hanzbrady here can modify your mani to accomodate your WG.
hanzbrady
04-16-2018, 11:54 AM
TIAL MV-S on an OEM manifold is a great option, hanzbrady here can modify your mani to accomodate your WG.
Thanks for the shoutout! Feel free to DM me with any needs :)
koukimonst3r
04-16-2018, 12:29 PM
Thanks, thats lame.
What external did you opt for?
Went with the turbosmart 40mm ewg, that was the only thing in stock that day so I ordered it right away, would've gone with Tial to match my BOV but oh well. You'd have to pick a spring rate as well for the ewg to match your boost.
Engmus
04-16-2018, 06:14 PM
Thanks everyone for the help.
I'm going to grandpa the car for now, and save up some pennies to figure out what happens next.
I'll follow up long term with what happens.
Off topic: what latency numbers do you use for your sti injectors?
Engmus
04-17-2018, 08:05 AM
Off topic: what latency numbers do you use for your sti injectors?
I'd have to ask RS Enthalpy I don't have those numbers in front of me.
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