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Discussion Starter #1
Well now that I have decided to run 15 psi, I can't get it to boost past 10 or 12. Running the old cartech wastegate on a very pitted rough exhaust manifold surface i could not get more than 8 psi. a hose got too hot and popped off giving me 12 psi with no connection to the turbo(scary, but lame). So new toys were in order. I bought and installed the Tial 38mm wastegate, I got about 10 psi, with very little diference with changes to the old Boost Controller. I decided to buy a DNA manual boost controler(cheap and well recommended). Upon installing it as the tial setup recommends(BC betweent two inlets on the wastegate) I got 15 solid on the first run, with steady decline after that to about 12. I heard lots more noise up front and the wastegate gasket had blown. Ok, so the tubine isn't getting enough exhaust to spool up big. After extensive search for new gasket, I cut up an old exhaust gasket to make new one for WG. Works great, much quieter, but still won't spool up past about 11, peaking at 13 in 4th gear(is this cause IC works better at 120 mph?). The max boost occurs with the BC turned all the way in(closed?) openning it up just lowered the boost down to abourt 6 psi at 9 turns out. This was wastegate set up as TIAL directs with the BC between the base inlet and the top inlet. I went with the recommendation of the BC and just went from the turbo hi side, to the bc to the WG base inlet. This gives TIal spring pressure (8psi) with it closed, back to about 11 with it open 1/4 turn and progessively less as i open it further. I lifted the car and looked over the whole boost side for leaks finding none. I'm not getting what I expected at all here. Is this boost controller bad?, or am I just missing the whole concept. Any suggestions?
 

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Discussion Starter #3
hmm, upon further research, I checked my stock BOV. passes air like it's not even there. Guess that is the next step, I have 2 others form other dead engines, all the same. ne1 having good luck with the sogi suggested bosch one?
 

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A Happy Dad
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I've got the Bosch, works great, was inexpensive.
you'll still experience some spiking and inconsistency with the mbc
 

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Discussion Starter #5
Thanx for the response. This is a very low budget project and as such things like new injectors won't be in the plan for a while. Prior owner ran 12.2 quarters with nitrous, but I didn't get the nitrous setup with the car. He had been running it with 19psi of boost for 12 years. He said the haltch will support 500 RWHP with 440 injectors.
Low budget supra? Well I bought the car with a blown engine for $1200 with the t04, 3"DP, Catech WG, Manual boost controller with solenoid(ie. dual range w/switch in cockpit),cartech IC w/HP, Haltech fuel comp, and Greddy cat back. While waiting for a JDM, my son's 89 was vandalized at the TOYOTA dealership, and totalled. I canceled my JDm order(hadn't shipped yet),
and bought his from the ins. co. for $300, it had a fresh JDM engine and new clutch put in by me about 6 months ago. So far, I had the turbo rebuilt for $300, had a crack in the ex. manifold welded, and bought the new WG and BC. Total investment so far < $2k. Lotta bang for the buck, if i just ddon't screw it up.

I would like a MHG, but the downtime and expense is too much to swallow right now, and I can always get another JDM for $900 in a panic. It seems It will cost nearly that much to do a MHG myself, and I have heard of some rather pricey shop jobs(like $2k or more). Maybe I will take one of the left over engine and re-build it myself with forged pistons and MHG, but it will be a while coming.
 
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Why would it cost that much to do a MHG yourself...

You buy one ~$200 and you install it.

It might take 3 days to do, but it should cost you anything but the price of a MHG and if you wanna run higher then stock boost its the BEST mod you can do
 

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Discussion Starter #7
Seems I priced the top end gasket set at about $250 from toyota, plus the MHG cost, and will have to have the head and deck lapped to get a good enough surface for MHG. Then of course I need to use arp bolts to be sure the consistency is there. If it can be done much cheaper I may reconsider it.
 
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