[hobbit382]

okay I know the newer supras and rx7s had twin turbos but are sequential turbos. do you think we could make enough room to make them fit. if we could we could have say 9bs and a set of 399 and have the best of both worlds.


also would it be possible to have a superchager with the twin turbo, and have the supercharger disengage after the turbos spooled up. or even add boost after our 9b's started to cut off after 5 grand.

 

[hobbit382]

oh yeah another question. if we were getting boost from a sc at 3k and below would the turbos spool up a lot faster? because there would be increased air which would mean increased exhaust gases to spool up the turbo.

 

[TenshiVR-4]

It wouldn't really help the turbos spool, because they don't spool based on exhaust flow alone. You need to have engine load before the flow will be enough to build pressure. (you also need some heat transfer, but that's a little different.) Theoretically you could use a supercharged and twin turbo set up, however, you would probably be pushing too much boost into the engine. Also, I've seen a few first generation MR2's using a "twincharged" engine setup using a single turbo into a supercharger, however, I wouldn't try it with our engines. The only quad turbo charged engine I've ever even heard of is the Veyron which is a quad turbo W-16 (or is it W-12?) that pushes in excess of 1000hp (at the flywheel anyway). Personally, I wouldn't even think of adding a third or fourth turbo to our cars, as our engine is too small to even need that much more flow. If you get a set of turbos that will match the engines displacement, you really don't need the extra turbo(s) anyway. Heck, the IHI ball bearings will hold 25psi to redline (on the stock engine, thats around 530hp anyway).
(I know that some of the above information is missing small things/possibly incorrect, however, this is a basic explanation)

Also, the supra twin turbo (93-97) did not have a sequential turbo setup. The RX-7, however, did. Either way you look at it though, twin turbo cars are designed to decrease spool time using two smaller turbos to achieve the same amount of boost as a larger single turbo, just with less boost lag. The RX-7's sequential turbo system doesn't cause one to spool early, the other to spool later, with both pushing at the same time, it actually uses one for low end boost, and the other is used for high end boost while the first (and smaller) shuts down. In essence, it's a single turbo system that uses two different turbos, one for low end, the other for high end. Quite an intelligent system though. I could explain how it works (or atleast the most simplistic and probable way it would work) but I won't annoy everyone with my babbling.

 

[SPD4XTC]

must admit that this is an interesting thread though ..

 

[gte853y]

I personally like the idea. In fact there are a lot of race cars that have a quad turbo setup or a sc and tc. The reason they do this is to virtually eliminate lag. By using a combination of small and large turbines, you can maintain a very nice boost curve across the entire rpm range starting as low as 1500 rpms. Now remember that these turbos are custom built to maximize their efficiency so you are looking at some might big bucks just to tune and make the turbos. You can do the setup though and have it only boost 10 psi if you want, but if you were to put that much money into the car you might as well put in the extra and have your car race preped so that it can handle like 25 psi or something crazy like that.
P.S. who had their car running on a stock engine with ~27psi? I remember reading about that.

 

[4u2nv]

WOW...I had no idea the RX-7 was set up in that format. It is definatly interesting considering me and my friends were arguing about the topic last night...and why they actually call them Twin Turbo's.

 

[TenshiVR-4]

But keep this in mind, Ari Yallon runs around a 9.5 quarter mile with the stock sequential turbo set up on his 93 RX-7. Also, with all wheel drive you really don't have to worry about turbo lag, you just need to worry about launching right. When you get to higher horsepower levels, then you have to worry about breaking loose. Easiest way to correct that is perfecting your launch, or using something like the MSD DIS - 4.

Also, while we don't have a sequential turbo setup like the RX-7 (it uses exhaust gasses and the wastegates to control exhaust flow at different RPM ranges) our (and the Supras) setup is somewhat similar. In our cases, the rear turbo (closest to the firewall) begins spooling first because of more intake flow, then the second kicks in just after that. If you want to see what I'm talking about, pull off the Y-pipe and look at the intake pipe that splits to each turbo just after the mass. It's got a lopsided shape to allow more flow to the rear turbo. And ninety percent of the time, the rear turbo is the first one to blow. My front turbo is fine (I'm waiting for new turbos and in the middle of my own turbo swap) but the rear is just torn to shreds.

 

[nitroucf]

The Oshkosh Phoenix 8X8 fire control vehicle uses turbos as well as a supercharger....it produces 114 psi with a SOHC 16-valve 2stroke diesel v8 of 12.054L displacement. Its not exactly a sports car, but it does have all wheel drive.

 

[nytemyst]

Also, the supra twin turbo (93-97) did not have a sequential turbo setup. The RX-7, however, did. Either way you look at it though, twin turbo cars are designed to decrease spool time using two smaller turbos to achieve the same amount of boost as a larger single turbo, just with less boost lag. The RX-7's sequential turbo system doesn't cause one to spool early, the other to spool later, with both pushing at the same time, it actually uses one for low end boost, and the other is used for high end boost while the first (and smaller) shuts down. In essence, it's a single turbo system that uses two different turbos, one for low end, the other for high end. Quite an intelligent system though. I could explain how it works (or atleast the most simplistic and probable way it would work) but I won't annoy everyone with my babbling.

the 93-97 models supras were sequential turbo cars just like the rx-7. Only the 300zx and the GTO were the true twin turbo cars. Its possible to supercharge and twin turbo charge the car. but you would have limit your boost because you cant turn off your supercharger since its belt driven. Probably run the supercharger at like 4 lbs of boost and the turbos at around 15lbs and you have a total of 19 lbs and you would practically have no lag.

 

[Deathsled]

all you gotta do is develop your own invention for turning the supercharger off, a simple little mechanism for disengaging it from the belt or whatver (does the A/C compressor work like that?) then we're cookin

 

[cooleyes007]

So you want no lag but turbos at the same time huh. I got an idea! NOS. hehe, Just spray 50 shot to the ic, you'll virtually have no lag, plus a safe coolant. cheaper than that whole supercharger deal. Just my .o2cents

 

[ILanda]

do superchargers come with wastegates???
and what rpm does the turbos spool up??

 

[brainfood]

If you want to see what I'm talking about, pull off the Y-pipe and look at the intake pipe that splits to each turbo just after the mass. It's got a lopsided shape to allow more flow to the rear turbo.

if this is true when i get my new ecu and it is speed density will both turbos spool equally becuase the intake will just be a pipe with a filter on it?

 

[mcvicker]

Also, while we don't have a sequential turbo setup like the RX-7 (it uses exhaust gasses and the wastegates to control exhaust flow at different RPM ranges) our (and the Supras) setup is somewhat similar. In our cases, the rear turbo (closest to the firewall) begins spooling first because of more intake flow, then the second kicks in just after that. If you want to see what I'm talking about, pull off the Y-pipe and look at the intake pipe that splits to each turbo just after the mass. It's got a lopsided shape to allow more flow to the rear turbo. And ninety percent of the time, the rear turbo is the first one to blow. My front turbo is fine (I'm waiting for new turbos and in the middle of my own turbo swap) but the rear is just torn to shreds.

I can vouch for that as well, when my turbos went it was my rear turbo. The front one was in great shape. But what a better time to upgrade turbos then when stock ones go!!!

 

[Vr4me]

Last week I was going to buy a supercharged 1995 Cobra and it didnt seem that fast. It was running 9psi boost, but I couldnt really tell it was supercharged until the I was in the upper rpm range, but with turbos the boost seems to work well in the low and high rmp range. So would there really be a benefit to running twin turbos and a blower.

 

[hobbit382]

I'm pretty sure you there are superchargers setup with a clutch type system so you can turn it off. so you could have it on before your turbos spool and then after you stock turbos start to die.

technically speaking it would be cheaper to have a supercharger that nos. how many times could you fill a nos bottle over the life of a supercharger. besides I heard its not good to get your engine to hit nitrous at anything below 3k. if nitrous is so cheap then why don't they put them on cars stock instead of turbos or superchargers. plus doesn't it eat the life of your engine?

If you got a used supercharger off of ebay for 200 bucks and called that guy that makes them for the dhoc I'm sure we could make one for less that 2 grand. and think about it how much is a turbo upgrade? and this would be better.

 

[omnip_1]

A huge single and a supercharger would be bad ass. Best of both worlds.

 

[TenshiVR-4]

That's what the first gen MR2's use, huge single turbo with the stock supercharger.
Nitrous only eats the life of your engine if you don't use it carefully. Nitrous basically adds liquid nitrogen and oxygen into your engine and makes you run lean. That is unless you make sure you don't run lean (larger injectors, fuel controller). That's why you see stuff melt (mostly cylinder heads and oil rings) when people use too much NOS. Also, Superchargers can eat the life of your engine as well. Though only a fraction of the amount that Nitrous does. It's one more belt the engine has to turn, adds weight on the crankshaft, and also, either way you look at it, pressurizing the intake charge on an engine will eat the life of the car. And in that sense, turbos eat it also.

 

[ajimbo]

do superchargers come with wastegates???

sorry.
I thought it was funny....

no offe. man.

 

[Feral]

Also, while we don't have a sequential turbo setup like the RX-7 (it uses exhaust gasses and the wastegates to control exhaust flow at different RPM ranges) our (and the Supras) setup is somewhat similar. In our cases, the rear turbo (closest to the firewall) begins spooling first because of more intake flow, then the second kicks in just after that. If you want to see what I'm talking about, pull off the Y-pipe and look at the intake pipe that splits to each turbo just after the mass. It's got a lopsided shape to allow more flow to the rear turbo. And ninety percent of the time, the rear turbo is the first one to blow.

Well this isn't true. What causes the turbo to spool up has very little to do with the intake shape (assuming there's enough intake volume), but rather the exhaust manifold design and pressure ratio. Both turbos get 3 cylinders, so unless the 3 cylinders for the rear turbo are different thant the front 3, or if our ECU controls the solenoid in a wierd way which would be gone the second we upgrade to an aftermarket boost controller, our turbos both spool up at the same time. We have a true dual system, nothing tricky like the supras or the RX7's.

Now on topic we could do a quad turbo but the starter turbo would have to be smaller than a 9b and the larger one would have to be 15G or bigger. Shoe horn that under your hood and I'll give you an award . When it comes to SC or nitrous I'd say go with the nitrous. Balancing a SC and a pair of turbos is tricky. I think you could do it but you'd have to run very low boost on the SC, and then run less high end boost on the turbo's. Plus your Y pipe would have to be reworked considerably and finally you' have to fit the SC somewhere. I love the idea, but it's VERY challenging.