Guest Loose_Screws Posted August 10, 2005 Share Posted August 10, 2005 OK.. I have max'd out a T3 at 18psi, power falls off after 4.5K rpm. My question is, with my setup, what pressures should I be running, er rather what flow? With MSnS 'extra' controlling the boost controller, I can set it up to whatever boost at whatever rpm. So...I could run 15 psi at 3,500 rpm and 9 psi at 5,500 rpm, if so desired, I just don't know what to run. I really don't see myself upgrading turbos, so that is ruled out. Here's a look at my graph from the dyno. Mod's are big FMIC, 440 injectors, 'extra', T3, P90 head, turbo pistons, stock F54 block (or whatever comes in '77). Stock P90 cam, stock cam timing. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted August 10, 2005 Share Posted August 10, 2005 100HP = 10lb/min is what I usually use. T3 60trim max out at 30lb/min at 2.1bar with 65% efficiency so with 275WHP, I think you are about 30lb/min so you really can't move much more air. (unless you up the boost) It'll make more useful power if you do spike in lower rpm but you are more likey to detonate in the torque peak so if you want to stay safe, I would go with what you got, just shift early to stay in the powerband. basically, you are out of a hair dryer. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 10, 2005 Share Posted August 10, 2005 I think keeping the boost at a set level from onset to redline is the way to go. I agree with Yo2001 you dont want a much higher boost at low rpm, pressures get really high around peak torque and you risk detonation. Also, no point in lowering boost at higher rpm, as torque and cylinder pressures fall off dramatically as it is, so you want to keep boost up. Though it seems a lot of peoples setups do fall a couple psi by redline. I have set mine up to stay at 13psi all the way up. I say, turn it down a bit... 18psi is killer on a T3, you say you don't want to upgrade your turbo any time soon 18psi might not give you a choice in the matter. Remember, your MS tune is FAR from optimized, turn the boost down a bit and tweak that MS, you'll probably come away with about the same power, a much happier turbo, much cooler intake air, etc. etc. Quote Link to comment Share on other sites More sharing options...
Guest Loose_Screws Posted August 10, 2005 Share Posted August 10, 2005 Thanks for the info guys! Yosuke, we gotta go back to the dyno. I found out the IAT sensor was bad and was giving false air temps to the MegaSquirt. Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 10, 2005 Share Posted August 10, 2005 Seems like good power to me! Could be the stock cam is done at 4500 or the valve springs are a little weak. Maybe a some 0.020" thick valve springs shims under the outer springs and a tighter lash would give you a few hundred more rpms. Wow! 275hp at 18 psi of boost. Who would have guessed that? Quote Link to comment Share on other sites More sharing options...
Thumper Posted August 10, 2005 Share Posted August 10, 2005 Alittle while ago I played with my t3 turbo at 23psi. I compared it to 20psi and there was about 10hp and 10lb-tq different. The car did handle the 20psi at 2800rpm then dropping down to 18psi by 6k for about 2 months. I sold the engine and turbo after that so I am unsure on how much longer it would have lasted. I agree bastaad 18psi is just asking to replace the turbo. My recommendation would run 15psi. You would only loose 10hp or so but your power would be more smoother. Less torque but with almost same hp. Also there are people who have been running 15psi for a year or two on the stock t3. I would concentrate on cleaning up the a/f ratio alittle to get the more power you want. Good luck Quote Link to comment Share on other sites More sharing options...
yo2001 Posted August 10, 2005 Share Posted August 10, 2005 Thanks for the info guys! Yosuke' date=' we gotta go back to the dyno. I found out the IAT sensor was bad and was giving false air temps to the MegaSquirt.[/quote'] Offcourse the IAT was bad, it was reading lower than the ambiant temp. lol I would like to to add, the P90 mildly ported by me. Quote Link to comment Share on other sites More sharing options...
Guest SBD Posted August 11, 2005 Share Posted August 11, 2005 I say you go external combustion. Quote Link to comment Share on other sites More sharing options...
Guest Loose_Screws Posted August 21, 2005 Share Posted August 21, 2005 Woot Woot!!! SBD made a three pull tune for me at a dyno comp. tonight. Made 280rwhp on first pull and 292rwhp on my last, 14psi! I think the timing was like maybe 18 degrees? Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 21, 2005 Share Posted August 21, 2005 now THAT sounds just right See, told ya you could make same power with way less boost. Nearly 300whp at 14psi on stock T3... I'm extremely envious! And now you're not outright KILLING your turbo... I'd think it could live long and happy at 14... I've been running 13/14psi for almost two years now, and last I checked a couple months ago there was still no discernible shaft play, and no sign of oil seeping past the bearings. Anywho, that amount of power really speaks highly of the capabilities of MS, and your tuner! Post the new sheets if you get a chance Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted August 21, 2005 Share Posted August 21, 2005 Wow, great numbers! Can you post your timing map as well? Thanks, Mario Quote Link to comment Share on other sites More sharing options...
KTM-EXC Posted August 21, 2005 Share Posted August 21, 2005 Wow!! Those are some great numbers. Quote Link to comment Share on other sites More sharing options...
Guest SBD Posted August 22, 2005 Share Posted August 22, 2005 HAHA, post a new thread, I couldn't find this one at first. The car definitely responded well to leaner a/f (which I found out the first dyno trip). I think the car REALLY liked the timing. Quote Link to comment Share on other sites More sharing options...
Guest Loose_Screws Posted August 22, 2005 Share Posted August 22, 2005 HAHA' date=' post a new thread, I couldn't find this one at first. The car definitely responded well to leaner a/f (which I found out the first dyno trip). I think the car REALLY liked the timing. [/quote'] I will start another thread, start asking questions about timing again too. We also need to consider the comp. ratio is stock, which is 8.5:1? Somebody help me here. Stock bottom end, ZX turbo pistons, P90 head = what compression? Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted August 22, 2005 Share Posted August 22, 2005 If it's a stock (internallly) turbo motor, then 7.4:1 CR. If you use flat tops, its close to 8.5:1, with HIGH QUENCH. If I ever rebuild my motor, I'm probably going with this setup. Mario Quote Link to comment Share on other sites More sharing options...
Guest Loose_Screws Posted August 22, 2005 Share Posted August 22, 2005 If it's a stock (internallly) turbo motor' date=' then 7.4:1 CR. If you use flat tops, its close to 8.5:1, with HIGH QUENCH. If I ever rebuild my motor, I'm probably going with this setup. Mario[/quote'] It's a stock N/A motor that came in the car (1977) with P90 head, turbo pistons, and the rest unmodified. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted August 22, 2005 Share Posted August 22, 2005 It's a stock N/A motor that came in the car (1977) with P90 head, turbo pistons, and the rest unmodified. Pretty sure its 7.4:1. Mario Quote Link to comment Share on other sites More sharing options...
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