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View Full Version : RS3871 Wastegate adjustment?


Dolby109
02-13-2014, 08:17 AM
I have just installed a new Isis RS3871 Turbo (similar to 2871R) and it supposedy has an adjustable wastegate.
I need to adjust it to low boost until I get the car tuned.
I was told to adjust the boost down you lengthen the wastegate rod, which makes sense because it is easier to open. So I lengthened the rod about 6-7 full revolutions to where it's not hard at all to put the rod on the arm.

I go out and test and as soon as I punch it I see the car hit 15psi and I shut it down. Another brief test also showed it easily trying to go past 10psi.

So did I adjust it wrong, or what am I missing here? I thought the stock boost on these was 14psi.

codyace
02-13-2014, 08:24 AM
Make sure that the arm isn't binding as it opens, and make sure that the flapper is opening all the way too. The longer the rod is adjusted, the more open the flapper will be, so it vents of fmore exhaust. Some cars just have strange runaway boost issues, which is why I started modding the OEM manifold to a utilize and aftermarket wastegate like a tial MVS

Dolby109
02-13-2014, 12:01 PM
Everything with the rod and flapper arm appeared to hinge and work fine when it was off the car. I'm pretty sure the wastegate is opening at 15psi because it briefly caps there.

So is adjusting the rod out to lengthen it the only way to lower the boost, or is there something I am missing?

Dolby109
02-14-2014, 12:31 PM
Seriously, has nobody successfully adjusted an internal wastegate before???

Fuego
02-14-2014, 12:45 PM
Lengthen the rod so you don't have to pull it at all to put it on.

Dolby109
02-14-2014, 04:43 PM
I'll try it but that sound like it would make it take a lot longer to spool if the exhaust was leaking through it.
Is this what you did to get low boost?

Fuego
02-14-2014, 05:00 PM
Well let me amend that to just a mm of pull to get it on. I'm basing that advice off my HKS actuator. Every single bit of advice I found in the forums were flat wrong and I ended up a few rotations from no pull to fit for 12 lbs.

By the way, where are you pulling vac from for your actuator?

Dolby109
02-14-2014, 09:47 PM
The Turbo outlet on the 3871 has a fitting with a short vac line that goes straight to the wastegate.
Supposedly the stock boost on this is ~14psi, and I have adjusted the arm out to where it is barely tight.

I might try and do some testing with a compressor to see when the wastegate is actually opening. Every time it hit ~15psi while I was driving I shut it down fast, its possible it could have kept climbing.

fliprayzin240sx
02-15-2014, 02:30 AM
I've always had issues with GT2871R flapper hole being too small. I usually mill it out to almost the size of the flapper to eliminate boost spike, might be the same situation with these turbo. If lengtening the arm some more doesnt help, might have to mill the hole out.