Wednesday, September 23, 2009 - 09:53 pm, by: Tim Hutchings(One_jay_zed)
Some of you longer standing members may remember a few topics of mine involving epic ruggedness (but always seem to turn out well), classic being my FMIC fitted with factory piping. Worked like a charm.
So last week I was lucky enough to score myself a heavily modified JZZ30. Among other things, it came with a T3T4 turbo and external wastegate. Pretty good? It was only boosting 7 pounds, it was reasonably quick (faster than a stock TT by far) but I wasn't really getting that kick that I was after. After hunting around the workshop for some kind of bleed valve, I tried a couple and got sick of the spiking! I'm yet to get a FCD so trying to set my boost to 14psi was nigh impossible, it would spike to 15, boost cut, then drop to 13 and that was about as good as I could get it. So I decided to try something new (having lots of spare actuator hose) and got out a drill and a 1mm drill bit.
I started by carefully drilling one small hole into my actuator hose, the boost rose to a very stable 9psi. Repeat - 11psi, and one last time, reached a perfect 14psi. Rough much? Some may think so, but after trialing this method I'll never bother with boost controllers again under 15psi, it's worked perfectly for my single turbo but I wouldn't recommend it on twins unless the actuators were bridged.
Wednesday, September 23, 2009 - 10:13 pm, by: Walter Gillmore(Cl33pa)
good enough but watch those holes as they may split(unlikely in the short term) and spike your boost. reading this just gave me a mad flashback of when we used to do our own re-jetting of dirtbike carbies solder plug holes to lean out bottom end fuel and drill larger holes to give the top end a tiny bit of richness so they could hold powerband longer without burning the rings out
i have done a backyard job on an old vg20et u11 maxima bluebird lol. worked quite well, brass t piece off wastegate line. length of hose to inside the cab and a clamping block to bleed the air. that was a while ago when i started playing with turbo cars, bout 10 years or so now. lol. it held the boost quite steadily until it was opened past the 1/4 mark then it spiked hard. lol. held a steady 12 psi.
ps ive enlarged my text browser settings lol and read your post thrice. hahaha
great to know someone is thinking outside the square. a rough guide perhaps to boost control.. lol 1mm hole = 3psi on a single turbo.
Wednesday, September 23, 2009 - 10:27 pm, by: Tim Hutchings(One_jay_zed)
Hmmm in my experience nothing is certain when dealing with turbos. It was surging like a bastard when I first got it, had to remove the turbo/mani etc and mani-seal the lot. Fixed it a wee bit and raised the boost from 5 to 7. Now that the boost is higher it is MUCH less laggy (it was pretty much nothin, nothing, nothing, BOOST) so it's more enjoyable to drive. The wee bit of lag on bottom end is great for traction also
If anybody wants to try this method out themselves, rest assured that if you do it a little at a time it isn't unsafe BUT do it bit by bit and keep an eye on your boost gauge!
Wednesday, September 23, 2009 - 10:52 pm, by: Walter Gillmore(Cl33pa)
yes also noticed that with the maxima turbo. boost came on a couple of hundred rpm earlier and hit a bit harder and stayed stronger longer, the vg20et was a very smooth high rpm engine. redline at 7800 i think it was. something ridiculous for a stock car.
here are a couple of pics i dug up of the maxima about 5 years ago when i did some more work on it for a mate. custom mounted turbo, relocated to have the compressor outlet facing underneath the front headlight. direct to intercooler off an evo4, re worked stock front bank cast manifold (turbo was mounted here behind the radiator, stock, so i jigged up the other flange that mates the other bank to the exh system. chopped off the turbo mounting flange and welded it all up together using mild steel pipe sections to bridge the gap left behind), fabricated custom high mount 'joiner manifold', fabricated the custom dump pipe with wastegate seperator.
a couple of tantalizing foot pics for those sarah jessica parker fans out there
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solder plug holes to lean out bottom end fuel and drill larger holes to give the top end a tiny bit of richness so they could hold powerband longer without burning the rings out 
