91GranSport Posted August 21, 2003 Author Report Share Posted August 21, 2003 What you're talking about is a twin turbo set up with "sequentially timed" twin turbos, rather than "parallel" twin turbos. Yes, there are vehicles out there like that. Here are a few examples: Mitsubishi 3000GT VR-4 Nissan 300ZX Toyota Supra Twin Turbo How they work is the first turbo kicks in at a lower RPM while the other turbo simply "idles". The first turbo gives you decent low end power (over stock) until the second turbo has enough boost to build pressure. From that point on, both turbos work together like a "parallel" twin turbo system and you have lots of top end power. It's like getting minor turbo lag twice but at least you have decent power throughout most of your useable RPM range. For all you guys who know alot of shit about forced induction answer this. So far from what ive learned you can set turbos so the lag is where you want it. Why cant you get a twin turbo set up, set one turbo so there is no lag and have it die out around 4K, but set the other turbo to kick in around 2.5k-3k and have that last almost the rest of the power curve? That way you have forced induction throught the whole curve and nonstop slam back in ur seat power? Quote Link to comment Share on other sites More sharing options...
91GranSport Posted August 21, 2003 Author Report Share Posted August 21, 2003 Essentially you're correct, although the "sequentially timed" twin turbo set ups require individual plumbing for each turbo so that they don't fight each other off. For a better understanding about forced induction check out this awesome website that explains a lot of shit about cars in general. http://autozine.kyul.net/technical_school/tech_index.htm You could try to do a setup like that... Problem is how do you divide the system? The better TT setups will split the banks of the the motor and use a common plenum to build common boost in, more exotic setups will even completely divide the engine banks and have two "sealed" and completely separate systems each fed by one turbo. What you are proposing would require both turbos(of different sizes to account for spool time) to feed into a common plenum, but when the first is boosting and the bigger turbo is not you would simply be backfeeding the second turbo and venting your boost. This would be vice-versa in the high range when the first or smaller turbo dies off and can't supply the CFM demand. Essentially the impellers would be fighting each other at both ends of the rpm range. Now I'm not really good with T or TT setups but this is what occured to me. Although it's a ford, this a good read for turbo guys: http://www.hotrod.com/techarticles/42798/ Quote Link to comment Share on other sites More sharing options...
91GranSport Posted August 21, 2003 Author Report Share Posted August 21, 2003 Dude, I don't know who this Luke guy is I'm curious about his TGP. First off, is his car faster than yours? Also, is his car stock? Finally, is there anything you can do to a TGP that'll make it outperform the ever popular Gen2 W-Body with the L67? Now, seeing a TGP beat a GTP/GS would be wicked! problem. the supercharger wont just die off at 3500 tho, it will still be making boost. so now you have 6-7 max psi from the blower, and then 8-9 psi from the turbo. now i dont think you can just add, but 14-16psi is a fuk of a lot of boost, especially for an aged motor that isnt dependable as it is(3.4 DOHC). as for the 3.1, i think a well tuned turbo would do just fine. bigtime spool at 2k, but it will still pull to 6. if any of you have ever ridden in Lukes TGP, it is a monster off the line. mega torque and it carries it well to about 5-5.5k. so with this low of a redline, a well tuned turbo will do just fine. Quote Link to comment Share on other sites More sharing options...
Aaron Posted August 21, 2003 Report Share Posted August 21, 2003 i use luke as an example cuz i rode in his car, and saw him run at the track, and raced it. he has a 1990 TGP, converted to 5-speed, with 12psi of boost. mad tq. i can beat him, i did so at the track by about a half second 8) . his car is fast, just lacks in the high end, which is where my Z34 shines. now i can beat a stock-nearly stock GTP os GS. i just pull them on the high end. so it wouldnt take much for luke to be beating them. now when luke's car us up here in CO, it could walk away from me. thats cuz a N/A car is hurt twice as much by altitude than a turbo or SC car. so at 1000 ft, i walked him, at 7000 he beat me by about how much i beat him. which is why im so impressed that i can beat a GTP, even at a really high altitude. Quote Link to comment Share on other sites More sharing options...
brian89gp Posted August 21, 2003 Report Share Posted August 21, 2003 A parallel twin turbo (ie 3000GT) is for drivability purposes. You can have 2 small turbo's with little lag and both of them combined will compress enough air for the engine, a single turbo capable of the same airflow will have more lag. A sequential turbo (Toyota Supra) is basically a small turbo and a large turbo. Until a certain rpm the small turbo is being used, when that rpm is reached butterfly valves operate in bot the intake and exhaust to shut the small turbo down and start using the large one. The entire thing is a very complex system especially when you add in valves and pipes so that the large turbo gets pre-spooled, etc. This setup gets you both the good lag free low end and great airflow for the upper rpm's. Now believe it or not a single turbo is almost always more efficient then either twin turbo setups, note i said efficient and not drivable. Take a given engine, you have a turbo that is super efficient but the thing doesn't hit full power untill 6000rpm; now take 2 smaller turbos that combined are less efficient but now spool at 3000. Everything is a large balancing act when it comes to turbo's Quote Link to comment Share on other sites More sharing options...
RomeoZ34 Posted August 22, 2003 Report Share Posted August 22, 2003 Aaron, you can pull on a GTP?? Your kidding me!! I have NEVER EVER heard you say that before. Oh ya, I forgot about those 400 other times BEFORE you blew your motor Quote Link to comment Share on other sites More sharing options...
91GranSport Posted August 22, 2003 Author Report Share Posted August 22, 2003 You fuckers and your fast cars... Seriously though, that sounds great. You guys keep up the good work. Not that I would want to see any Gen1 vs. Gen2 competition, but that's great to see how our Gen1 cars are still kicking ass up to this day. I'd like to have my '91 Regal GS as quick as you or Luke, but before I star souping up my ride I have to replace the tires and shock, do some bodywork, repaint the body, etc... i use luke as an example cuz i rode in his car, and saw him run at the track, and raced it. he has a 1990 TGP, converted to 5-speed, with 12psi of boost. mad tq. i can beat him, i did so at the track by about a half second 8) . his car is fast, just lacks in the high end, which is where my Z34 shines. now i can beat a stock-nearly stock GTP os GS. i just pull them on the high end. so it wouldnt take much for luke to be beating them. now when luke's car us up here in CO, it could walk away from me. thats cuz a N/A car is hurt twice as much by altitude than a turbo or SC car. so at 1000 ft, i walked him, at 7000 he beat me by about how much i beat him. which is why im so impressed that i can beat a GTP, even at a really high altitude. Quote Link to comment Share on other sites More sharing options...
91GranSport Posted August 22, 2003 Author Report Share Posted August 22, 2003 Funny, I always thought the 3000GT VR-4 was a "sequentially timed" twin turbo set up. Also, I read that on a "sequentially timed" twin turbo set up, the smaller turbo remains active throughout the RPM range, it's just a matter of the larger turbo "idling" until a certain RPM. Either way, thanks for the info. By the end of the month I'll know enough to turbocharge every motor I have ranging from my Craftsman lawnmower to my KitchenAid blender. Dude, we should seriously take over GM. A parallel twin turbo (ie 3000GT) is for drivability purposes. You can have 2 small turbo's with little lag and both of them combined will compress enough air for the engine, a single turbo capable of the same airflow will have more lag. A sequential turbo (Toyota Supra) is basically a small turbo and a large turbo. Until a certain rpm the small turbo is being used, when that rpm is reached butterfly valves operate in bot the intake and exhaust to shut the small turbo down and start using the large one. The entire thing is a very complex system especially when you add in valves and pipes so that the large turbo gets pre-spooled, etc. This setup gets you both the good lag free low end and great airflow for the upper rpm's. Now believe it or not a single turbo is almost always more efficient then either twin turbo setups, note i said efficient and not drivable. Take a given engine, you have a turbo that is super efficient but the thing doesn't hit full power untill 6000rpm; now take 2 smaller turbos that combined are less efficient but now spool at 3000. Everything is a large balancing act when it comes to turbo's Quote Link to comment Share on other sites More sharing options...
topless94style Posted August 22, 2003 Report Share Posted August 22, 2003 So if you had enough money to turbo/SC an LT1 what would you do? get one baddass turbo, or the sequential TT or a damn good SC? Quote Link to comment Share on other sites More sharing options...
91GranSport Posted August 22, 2003 Author Report Share Posted August 22, 2003 I'd get a supercharger for the LT-1. They're less expensive than a twin turbo set up and they're a proven modification. There are lots of supercharged LT-1s around, but very few twin turbo set ups. I've only come across two companies that build twin turbo packages for the LT-1, and both those packages are well into the $10,000+ range. The superchargers don't provide the same power gain on the LT-1 as the twin turbos do, but they're less expensive and easier to install. On the LT-1, even simple maintenance like changing the spark plugs can take you 8 hours. So if you had enough money to turbo/SC an LT1 what would you do? get one baddass turbo, or the sequential TT or a damn good SC? Quote Link to comment Share on other sites More sharing options...
brian89gp Posted August 22, 2003 Report Share Posted August 22, 2003 Funny, I always thought the 3000GT VR-4 was a "sequentially timed" twin turbo set up. Also, I read that on a "sequentially timed" twin turbo set up, the smaller turbo remains active throughout the RPM range, it's just a matter of the larger turbo "idling" until a certain RPM. Either way, thanks for the info. By the end of the month I'll know enough to turbocharge every motor I have ranging from my Craftsman lawnmower to my KitchenAid blender. Dude, we should seriously take over GM. The 3000GT is a true parallel setup, there is a turbo for each bank of cylinders. Some sequentially turbos keep the small one spooled, but the Toyota setup (Supra and MR2) prespool the large one at a certain rpm and shut the small one down shortly afterwards. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted August 22, 2003 Report Share Posted August 22, 2003 Dude, I don't know who this Luke guy is I'm curious about his TGP. First off, is his car faster than yours? Also, is his car stock? Finally, is there anything you can do to a TGP that'll make it outperform the ever popular Gen2 W-Body with the L67? Now, seeing a TGP beat a GTP/GS would be wicked! i think so, altho i also think that the 3.1 pushrod engine with it's 6000 RPM redline isn't suitable for a BIG turbo - you'd have major lag and when boost came on you'd be close to redline. i think it would take at least a 3" exhaust, bigger turbo (T3 or?) & custom crossover pipe, bigger injectors, BOV, manual boost control, alcohol injection, Getrag 5-speed, and a WELL tuned chip. and then you have to worry about traction. i think a TGP modified like this would kick a stock GTP's ass. of course you can modify the s/c 3800 too, but it's got more cubes and probably more of an aftermarket to make things easier. joshua Quote Link to comment Share on other sites More sharing options...
Aaron Posted August 23, 2003 Report Share Posted August 23, 2003 the TGP, with 12 psi and a 5-speed, is wicked with the turbo its got. spools at like 2000(instantly), but it does shut down a lot 500 below redline. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted August 23, 2003 Report Share Posted August 23, 2003 yeah, the 3.1 MPFI's low end torque together with the T25 make for great off the line performance, ecspecially with a 5-speed if you know how to launch it really good. makes for a fun car to drive. man i wish i could drive Luke's TGP, or win the lottery and finish my turbo 3.1/5-speed CS project..... :? i got the TGP engine sitting in my garage, and have located one Getrag 284, and a few other 282's for replacement, so i guess i'm making some progress. anywayz, i'm close to having my GTS done soon and CAN'T WAIT to drive one of my own cars again. i'm hoping for high 14's with it. i plan on dyno'ing it in Ft. Collins soon and maybe even get some time slips next summer (i've never drag raced). later down the road i think i can easily get the GTS in the high 13's, mostly because there is much more of an aftermarket for the turbo dodge and practically none for the TGP. anyone in the CO area want to race my GTS when i get it done? (tim you don't count cuz you'll obviously kill me - but hey it would be fun anyway) after the Cutlass is turbocharged and i get another 5-speed, i'm not going expect more than low 15's/high 14's until i get a bigger exhuast, grainger valve, BOV, and new slightly bigger injectors. joshua Quote Link to comment Share on other sites More sharing options...
Aaron Posted August 23, 2003 Report Share Posted August 23, 2003 anyone in the CO area want to race my GTS when i get it done? ill take ya up on that offer i pretty much took Luke out at the track. a half second is a HUGE difference. and ill agree he still couldnt drive the car to its true potential, but he had tons of runs to get it right. its just that 3.1 couldnt keep up with the high end 7000rpm of the TDC V6 Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted August 24, 2003 Report Share Posted August 24, 2003 Aaron. you are going down. hehe joshua Quote Link to comment Share on other sites More sharing options...
Redfox340 Posted August 24, 2003 Report Share Posted August 24, 2003 Aaron. you are going down. hehejoshua Joshua, count me in sometime... my VR6 needs to be broken in! Love to see how many car-lengths I'm behind agaist your GTS. - Erik Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted August 24, 2003 Report Share Posted August 24, 2003 anyone in the CO area want to race my GTS when i get it done? ill take ya up on that offer i pretty much took Luke out at the track. a half second is a HUGE difference. and ill agree he still couldnt drive the car to its true potential, but he had tons of runs to get it right. its just that 3.1 couldnt keep up with the high end 7000rpm of the TDC V6 i'm not talking about my Cutlass, i'm saying my Turbo II GTS will take your Z34 (i admit i have around a 400lb weight advantage but i also have a smaller engine 4 cylinder engine). my turbo 3.1/5-speed Cutlass will probably need a few minor mods to take your Z34. and that is MINOR mods like grainger valve, BOV, bigger exhaust etc. but hey, we'll see if we actually race, it's all in good fun - i'm not a sore loser. joshua Quote Link to comment Share on other sites More sharing options...
Aaron Posted August 25, 2003 Report Share Posted August 25, 2003 im not either, i know my car pulls like hell, and i respect the people who beat it. and most the time, they get done and have a worried look like, damn, that lumina almost beat me. so it still makes me feel good. Quote Link to comment Share on other sites More sharing options...
kadoi Posted August 28, 2003 Report Share Posted August 28, 2003 my tgp will take your lumina right here right now...now questions asked lol Quote Link to comment Share on other sites More sharing options...
Aaron Posted August 28, 2003 Report Share Posted August 28, 2003 you wont run anywhere near me when i get it put back together, then ill be running 14s again instead of half hours. Quote Link to comment Share on other sites More sharing options...
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