brian89gp Posted June 28, 2003 Report Share Posted June 28, 2003 How can you tell wether the exhaust impeller is needing to be trimmed (ie, doesn't flow enough for high rpm's and acts as a major restriction so you cut the fins to allow better flow). The motor feels quite torquey right at 2.4k but above 3.8k or so it just doesn't seem to pull as hard as stock n/a even at 2psi of boost. It still revs to 6k easily but it doesn't seem to pull very hard on its way up there, on the other hand cruising at 2.4k I can fell it pulling much much harder then stock. Its a turbo that originally came on a 3.0 DOHC Supra motor, the exhaust side is stock and the compressor side has a larger wheel. Its on the 3.4 DOHC now. Since trimming the exhaust wheel is permenant I want to make damn sure it needs it first. Quote Link to comment Share on other sites More sharing options...
Redfox340 Posted June 28, 2003 Report Share Posted June 28, 2003 The ONLY thing I could think off [for research & development] is to get it check out by some fluid mechanics guys. They'll throw numbers / information at you up the ying-yang after they get accurate testing done. - Erik Quote Link to comment Share on other sites More sharing options...
TurboGTU Posted June 29, 2003 Report Share Posted June 29, 2003 I am not too fimiliar with the 3.4DOHC. But is you intakemanafold a doual stage intake like the Ford Yamaha 3.0 SHO Taurus engine ones. By that I mean does it activate butterflies or open and closes ports for high rpm operation. If so your High rpm butterflies aren't openning up. Just a guess. A turbo feeding a DOHC 3 liter shouldn't have too much prob feeding a 3.4 liter motor, at 2 psi yea easly-- but at 14psi, efficiancy drops like a rock or is not even possible to feed it that much. So it might not even be the turbo. Try looking for ristrictions on your pipes (exhaust,intake). If posible check your fuel curve for richness or lean mixtures. Your fuel pump might not be supplying enough fuel. OR YOu might not be used to the new power band. The so called pull might have moved lower on the rpm range and the power is seemless after that. Try dynoing the engine to see for any unusual power spikes ,dives, and fuel mixtures. Quote Link to comment Share on other sites More sharing options...
brian89gp Posted June 29, 2003 Author Report Share Posted June 29, 2003 The 3.4 is single stage intake. The turbo could hold 14psi on the Supra motor and is good for 350-400hp, since I am only wanting to run 8psi on a 200hp stock motor I think/thought it would work. Fuel curve and fuel pump are fine. On a motor that the stock torque peak was at 4k and pulled hard to 6.5k, now it pulls real hard at 2.5k and seems to loose it all shortly after that. Hopefully it is just I am not used to the powerband and the peak at 2.5k overshadows the upper rpm's, I hadn't driven my car for 3 months as well so I have forgotten how it used to drive. Quote Link to comment Share on other sites More sharing options...
timg Posted July 6, 2003 Report Share Posted July 6, 2003 clipping is bad. It drastically reduces the efficiency and powerband of the turbo. Tim Quote Link to comment Share on other sites More sharing options...
brian89gp Posted July 6, 2003 Author Report Share Posted July 6, 2003 And in extreme cases it allows you to use a smaller turbo on a larger motor. Anyways its just I am pretty sure the torque peak is now in the high 2k to low 3k range, possibly it was just overshadowing the rest of the powerband. The diaphram in the wastegate gave out (i had partially messed it up before) and managed to hit 11psi @ 3400 rpm with only 40% throttle so I have no doubt that this turbo will work fine. Just kinda got scared there for a minute after all the work I had put into it. Quote Link to comment Share on other sites More sharing options...
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