dj paul Posted January 6, 2006 Share Posted January 6, 2006 Hey guys, ive looked around and read up on this but i want to get a little bit more specific. My friend is not fabricating a TT exhaust manifold for me out of a stock turbo manifold (he a machinist) and im just wondering about doing a sequential turbo setup. It has intrigued me. Ive ridden in my friends sequential turbo rx-7 and i know rotarys are diff but it was an awesome *** car quick spool up at the biggening and then around 4k maybe less it started to sound and feel like a space ship or something. My plans for this car Are AutoX/street use. I have a daily driver so reliability is not too big of a problem but i would like it if possible. I know the plumbing to this is going to be hard, but what would be the best two turbos to use with a 280ZX motor running 9:1 CR with plenty of fuel, to utilize the sequential turbo setup. Quote Link to comment Share on other sites More sharing options...
EZ-E Posted January 6, 2006 Share Posted January 6, 2006 Goto http://www.speedshopthagard.com, you can see some the the pics of James Thagards setup with twin turbos. Im sure he would help you out with some ideas as well, this man is amazing with his knowledge and workmanship. Quote Link to comment Share on other sites More sharing options...
dj paul Posted January 6, 2006 Author Share Posted January 6, 2006 thanks man that looks great. i see he is running 2 mitsu turbos. hmmm... i wonder if he can help me out with my sequential turbo idea. Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted January 6, 2006 Share Posted January 6, 2006 thanks man that looks great. i see he is running 2 mitsu turbos. hmmm... i wonder if he can help me out with my sequential turbo idea. :)Not with fabrication:) Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted January 6, 2006 Share Posted January 6, 2006 Actually, sequential turbo are very non-linear in their power curve, and difficult to control in racing (curves). Had a friend that has owned ttRX7's, Supras - he's got a Z06 now... Quote Link to comment Share on other sites More sharing options...
dj paul Posted January 6, 2006 Author Share Posted January 6, 2006 :)Not with fabrication:) lol i know man, im just wondering about ideas and some more pictures of your setup if possible. im pretty good at fabbin up stuff. ive basically built my car from the ground up. ive had to make new frame rails floor rails and floors. and its completely gutted right now. you dont happen to sell custom intakes do you? ive found one like yours but i might not be able to buy it yet (buyin fiberglass rear quarters). and Q45man they arent linear? i thought the small one would help spool up the larger one. ive read numerous places that they would be great for autox but you know how the internet is. do you all think a TT setup like 240turbos would be better for AutoX or a sequential turbo setup? (sized correctly of course) Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted January 8, 2006 Share Posted January 8, 2006 There are actually 2 humps in the torque curve as you are accelerating - corresponding with the efficiencies of each turbo. Think like a 2 hump camel vs a 1 hump. The 2 hump camel will have its' second hump higher in the rev range and of course will have a higher amount of torque. If racing, you'd be better off with a single curve/hump for controlability reasons. Not only that, but even the TT RX7's and Supras go to Single turbos for POWER. For street and autocross, where instant acceleration is needed, two matched smaller turbos will spool quicker and still be linear - best of both worlds, though more expensive and involved. The real reason the ttRX7 went sequential is that wankels are notoriously dismal at providing low end torque - and sequential turbos do a good job of providing that on the street, but once again, what works on the track ain't neccessarily the same... Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 8, 2006 Share Posted January 8, 2006 You will notice most of the serious tuner shops in Japan convert the sequential twins to a single turbo when going for linearity. HKS came out with a single turbo cas t manifold for both the Supra and RX7 almost immediately. This is different when they are dual turbos operating in parallel--many times they keep twins then, and only occaasionally go with a larger single. Depends on how mig you want to go---dual 500HP turbos may be more difficult to package in a tight engine bay than a single 1000hp capable turbo mounted in a different location. Sequentials seem to be more of an advertising gimmick, than practical application, when dealing with serious horsepower. With the advent of the VNT GT35 series turbos, the best of both worlds is becoming more and more accessible. Now to find one with an A/R of .82 or .63 instead of the 1.06 that is everywhere... Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted January 8, 2006 Share Posted January 8, 2006 Here is an initial dyno graph from the twinturbo setup before the fuel was leaned out. This was 28psi and no nitrous. Car was running balls rich, but pulled well to 7K RPM even though it was only street tuned. I later leaned out the fuel based on the dyno graph, but never had the opportunity to dyno the car again. With the AFR set correctly the power should continue to climb to redline. 28psi and no nitrous felt much faster than 17psi and the 125shot which netted me consistent 133-134mph in the 1/4. Based on calculations this said the car was putting down ~490hp@wheels, which would be consistent with tuning changes. I thought the car would probably make ~480-490hp@wheels without nitrous. This was also pusing through an automatic. Quote Link to comment Share on other sites More sharing options...
dj paul Posted January 9, 2006 Author Share Posted January 9, 2006 after seeing what you guys are talking about. id rather go two small turbos. this makes most sense to me after seeing actual results, and the some info behind it. ive had a little more time to think and read and im going this route. now to the turbo sizing. im not going to need one for a little bit (as you can see from my web page) but you think 2 mitsu turbos would be best suited? im trying to stay under 300 for each turbo. Oh and you all will be happy to know that the front right frame rail is completely done right now, suspension mounts and all. I will update pictures on my site tonight or tomorrow. i actually put my drivers seat brackets in last night and got to sit in the car! i was so excited. the rail isnt that pretty yet but its 100 times stronger than stock. but to stay on topic (lol) what size turbos? thanks paul Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted January 10, 2006 Share Posted January 10, 2006 I would probably opt not to use the same 16G turbo's that I used. Was a bit laggy for the average guy. I don't know what you can expect for $300/turbo as you get what you pay for. I can sell you new Garrett units sized for your pleasure. Quote Link to comment Share on other sites More sharing options...
dj paul Posted January 10, 2006 Author Share Posted January 10, 2006 well im just trying to find some that i maybe could pick up out of a junkyard car or someone upgrading. how much would a TT setup cost with new garretts sized to hit boost in a range that would be good for AutoX. im not exactly sure. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted January 10, 2006 Share Posted January 10, 2006 Not sure about the US but we can get Subaru STI turbochargers VF22(?) for around USD300 each here in Aus. Roller bearing, minimal shaft play. Unsure how two would spool on a 2.8L, one spools like this on a 1.8L golf engine: http://www.msprotege.com/vbb222/attachment.php?attachmentid=36063 They're also probably a tad big for autoX being around a 350hp(ea) turbo. Maybe something else? WRX turbo? CA18DET turbo? You should be able to nick something new and little for $300/ea. Dave Quote Link to comment Share on other sites More sharing options...
dj paul Posted January 11, 2006 Author Share Posted January 11, 2006 sounds good man, ill have to look for those. any more suggestions? http://cgi.ebay.com/ebaymotors/Mitsubishi-3000GT-VR4-STEALTH-twin-turbo-turbos-NR-TD04_W0QQcmdZViewItemQQcategoryZ33742QQitemZ8029206360QQrdZ1QQsspagenameZWDVW possibly these? im going to try and find some more info on these. Quote Link to comment Share on other sites More sharing options...
dj paul Posted January 11, 2006 Author Share Posted January 11, 2006 im thinking t25 turbos off an sr20det. looks like you can get these all day for cheap. what about a t25/t28 hybrid. suppossedly t25s are a bit small, so would a hybrid be better giving a higher boost potential with the quick spool up of a t25? im decent at reading compressor maps but have no clue as to how to figure twin setups. do you just cut your airflow in half or something? Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted January 11, 2006 Share Posted January 11, 2006 well im just trying to find some that i maybe could pick up out of a junkyard car. You know what they say...if you go to the junk yard you get junk. Quote Link to comment Share on other sites More sharing options...
dj paul Posted January 12, 2006 Author Share Posted January 12, 2006 well you know what i mean, pick em up off of a stock car. im kind of on a budget, but the turbos will be the most expensive for me because i do all the other stuff myself. what do you think about the t25s i mentioned. possibly the t25/t28 hybrid? Quote Link to comment Share on other sites More sharing options...
Challenger Posted April 28, 2008 Share Posted April 28, 2008 Any info on the t25/t28, theres one for sale locally... Werent they on the 87-89 zxt? Quote Link to comment Share on other sites More sharing options...
Pellius Posted May 7, 2008 Share Posted May 7, 2008 I would probably opt not to use the same 16G turbo's that I used. Was a bit laggy for the average guy. I don't know what you can expect for $300/turbo as you get what you pay for. I can sell you new Garrett units sized for your pleasure. Me being an average guy and just out of idle curiosity, what turbos would you use? Quote Link to comment Share on other sites More sharing options...
evildky Posted May 8, 2008 Share Posted May 8, 2008 the 88-89 Z31 turbo's came with a single T25, the 90-96 Z32TT came with a pair of T25's Quote Link to comment Share on other sites More sharing options...
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