Supercharged Turbo?

[snyper2727]

I know this is probably a ridiculous question full of complexities in the answer but here goes....

I am wondering if I could utilize a turbo in a addition my Comptech supercharger?

I like the CTSC for down low grunt and power, but would like some high rpm high power with no lag from a turbo. I have seen on the net a few supercharged turbo systems done on other cars. I am guessing that the CTSC would be the bottleneck during high boost from the turbo. Not to mention the fuel curve headaches...but I was simply wishing for a glimmer of hope, because I LOVE the zero lag and flat torque of the CTSC, and would be really cool to have turbo spool up in addition....I know...I know...just where the hell do you think you're going to find the room for this in the engine bay?....right?

 

[matteni]

Sell your CTSC and buy a turbo system from one of the vendors that will design one for your needs. Do some research but you can get gobs of power early from a turbo and as much top end as you can handle. You will be trading some possible attributes you like about your CTSC - but if you are honestly thinking about both - you might not mind to have a near limitless upgrade path.

Good luck.

 

[matteni]

One more thing - if you do like your CTSC and want more power - you can also contact CompTech for the 9lb upgrade kit or perhaps even more power that has been rumored to be had.

------------------
Nick M

91' Red/Black with Many Mods
99' Honda Odyssey with Many Kids

 

[snyper2727]

"9lb upgrade kit or perhaps even more power that has been rumored to be had."

What do you mean "more power that has been rumored to be had"? The 9lb or some other mod using the CTSC?

Thank you for the responses Matenni....

 

[matteni]

I heard second hand on this forum that there may be a 12lb kit - but it sounded very expensive and with no intercooler option - not very practical. That said - CompTech knows about what they can / can't do and I am sure they can fill you in. When / if you get the details - please come back here and post what you end up doing and you impressions.

------------------
Nick M

91' Red/Black with Many Mods
99' Honda Odyssey with Many Kids

 

[Ryanmcd2]

I think if you are going to spend the money and want good power like low end torque and HP Turbo is the way to go. I had a RX-7 Twin turbo and the power was SUPER SMOOTH and had a TON of power 400+ HP outa a 1.3 liter. I also like the low end it had. I think the high reving NSX would work well with a turbo. Twin maybe the best because you can have low end and top end. Anyone doing a sequential with pre-spooling the 2nd would be the way to go. I think that would be too much work so dono if that would ever happen.

 

[matteni]

Another possibility is running NOS with your CTSC. Some people have reported doing this with success and it might be a lot cheaper way to go depending on your needs and why you are doing this.

 

[McAttack]

This is what I have and it's worked fine for me (so far). 9 lb CTSC w/a "pre SC" 50 shot of NOS yielding about 63 hp. This setup along w/CT I/H/E dynoed at 423.1 RWHP.

 

[sjs]

As alluded to by matteni, low-end torque is the forte of a good turbo system far more so than your CTSC and can also improve the top end, although it is still somewhat of a balancing act between the two even with turbos. (Aerodynes further broaden the power range, but that’s another story.) I could go on at length about the myths and misconceptions about “turbo lag” in modern systems but the bottom line is that turbos typically deliver far more “area under the curve” (on a dyno chart) than SCs. You can read many opinions about that on this site but it can be difficult to separate fact from fiction.

But to address your actual question, it would be possible to do what you suggest, but I’m not so sure of the outcome. As it happens I was (only half seriously) toying with the idea of a little test myself. I have one each of a CTSC and Bell TT and will be consolidating to a single car in the future. I bought the CTSC car intending to dump the blower and replace it with the turbos from my other car, which I will then sell. Anyway, it occurred to me one day that in a weekend I could move the turbos onto the CTSC car and run a sequential system just for grins. However, the turbos are quite able to spin up quickly and lack only in that they are sized too small to exceed a certain boost level (CFM actually) without over spinning to death. The CTSC might have its top end extended by the turbos pre-pressurizing the air, but can it do more than just get in their way?

A specially designed system with each component complimenting the other might be possible, somewhat similar to the sequential turbo systems that have been done in the past, but I don’t see how the extra hardware and complexity to mix SC and turbo would be justified.

 

[Gerry Johnson]

A well designed turbo kit will not have any lag that you will be able to fill, and will give you a lot of torque down in the lower rpm's where the NSX needs it most.

 

[4AU4LIFE]

Originally posted by Gerry Johnson:
A well designed turbo kit will not have any lag that you will be able to fill, and will give you a lot of torque down in the lower rpm's where the NSX needs it most.

If anybody knows this, Gerry does.

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92 RED/BLACK 5-SPEED

 

[snyper2727]

Awesome info guys, thanks for your time. I would prefer to stay away from NOS entirely. Something about the inconvience of having to fill the bottle, pay for it, and use it sparingly. You guys have to enjoy not taking the cheap route and saving money in the long run because there is generally no additional expense as associated with the NOS. Appears as if I had better save my pennies, get the block decked and sleeved, and go turbo. I don't mind a little lag as long as it is not as bad as the pain in the ass Supra I used to have, HKS GT2835 turbos, no power until 4800 RPM then, WHAM pure power, but little RPM left to play. Damn, I am glad I got rid of that car, nothing but probs, and no matter how much power a Supra can have, it will NEVER be or compare to the exquisite NSX. They all talk about G skidpad tests with the Supra, but we all know you can't do the same things in a Supra that you can do in an NSX. All the guys (and gals) here are great people with great attitudes and generally a more mature crowd. ( iam am 31) It is so much nicer to chat with you people than on the Supraforums.(YUCK)

As I continue to ramble and get off the topic I started, I just wanted to mention that I am currently on my second NSX. I began nosing around everywhere looking for a car comparable in price to the NSX I own, just for a change of car. Everything else pales in comparision to the NSX for the price, quality, balance, power(CTSC), rarity, and just straight out fun. (not to mention the excellent gas mileage while putting around town. Apparently, I have been completely spoiled by the NSX, and nothing else will cut it(for the price). I have $61K in my car. CTSC, shortgears, and 4.55R&P. I bought the car at 15K miles. So there you go another hopeless NSX addict.

 

[Mark911]

One good thing about a positive displacement FI system is that it is very linear, making boost at low RPM and high load very smooth and predictable. This is where cylinder pressures and subsequent internal component stresses are at the maximum. The Comptech system has proven reliable because IMO it does not impose high "spike" loads at low RPM like some turbo systems can generate if not very carefully controlled. These "spikes" loads lead to engine damage. However, a compound system using a turbo to feed a positive displacement pump could be a win-win. If sized properly to produce boost only at higher RPMs, the turbo would take over when the supercharger starts to level out, providing more boost when the engine's internal components can handle it. IMO, that's why the BSSC system works well (from a stress standpoint) as it puts little demand on the engine until well into RPM range. A turbo of course could produce boost much faster than the BSSC system and the supercharger would probably smooth out it's delivery which would be desirable to reduce spikey loads. Maybe a combo roots type supercharger (intercooled) combined with a BSSC type system (intercooled) with a larger pump would be the ticket (actually, you might not need a bigger pump as I don't know how much they are bleeding off to get the boost to come in eariler). This system would suffer from a lot of mechanical losses, but it won't have to worry about overcoming exhaust backpressure to fill the cylinders. On the other hand, since the turbo's turbine would be sized on the large side to delay onset of boost, you might not get much back presssure losses anyway. So maybe a combo turbo/roots system is the way to go. Anyway, food for thought. Mark

 

[Attitude Adjuster]

One good thing about a positive displacement FI system is that it is very linear, making boost at low RPM and high load very smooth and predictable. This is where cylinder pressures and subsequent internal component stresses are at the maximum. The Comptech system has proven reliable because IMO it does not impose high "spike" loads at low RPM like some turbo systems can generate if not very carefully controlled. These "spikes" loads lead to engine damage. However, a compound system using a turbo to feed a positive displacement pump could be a win-win. If sized properly to produce boost only at higher RPMs, the turbo would take over when the supercharger starts to level out, providing more boost when the engine's internal components can handle it. IMO, that's why the BSSC system works well (from a stress standpoint) as it puts little demand on the engine until well into RPM range. A turbo of course could produce boost much faster than the BSSC system and the supercharger would probably smooth out it's delivery which would be desirable to reduce spikey loads. Maybe a combo roots type supercharger (intercooled) combined with a BSSC type system (intercooled) with a larger pump would be the ticket (actually, you might not need a bigger pump as I don't know how much they are bleeding off to get the boost to come in eariler). This system would suffer from a lot of mechanical losses, but it won't have to worry about overcoming exhaust backpressure to fill the cylinders. On the other hand, since the turbo's turbine would be sized on the large side to delay onset of boost, you might not get much back presssure losses anyway. So maybe a combo turbo/roots system is the way to go. Anyway, food for thought. Mark

I don't know if you were refering to the comptech as the roots type. If you were, a Comptech Unit is not a roots style, it's a screw type.

 

[sjs]

One good thing about a positive displacement FI system is that it is very linear, making boost at low RPM and high load very smooth and predictable. This is where cylinder pressures and subsequent internal component stresses are at the maximum. The Comptech system has proven reliable because IMO it does not impose high "spike" loads at low RPM like some turbo systems can generate if not very carefully controlled... Mark

I'm not sure I buy that, in fact I'm pretty sure I don't except to the extent that without a proper stand-alone ECU most forced induction systems aren't well tuned over the full range of loads/RPM that are possible with a turbo. As you said, an SC is much more predictable in that respect. If the fuel map were represented as a spreadsheet with RPM on one axis and manifold pressure on the other, an SC would always operate through a relatively narrow band, but a turbo can hit a far broader range of cells. Add ignition timing vs. RPM & boost and a crude turbo system can get in danger far more easily than an SC. Other than that I don't see that "spike" loads are relevant.

If sized properly to produce boost only at higher RPMs, the turbo would take over when the supercharger starts to level out, providing more boost when the engine's internal components can handle it.

Somehow I just can't bring myself to define more power at lower RPM as a negative, so I consider your combination reversed. The BBSC can produce plenty of top end power, so if anything I'd have a very small turbo to fill in the bottom. However, I think that with a properly sized turbo you can get adequate response at low RPM and still be large enough to power the top end as seen on several current systems. (VTEC surely helps) I'm sure there's room for improvement but IMO not enough to justify such a complex and heavy hybrid.