Single or twin turbo?

[Dimer]

Since the NSX has a V6, I would think a twin turbo setup would be the best turbo option for our cars. But when I look at all the serious race cars (FXMD, Driving Ambition, LoveFab, Coz), they use a single turbo.

For track use, what is the best? If you had carte blanche, what would you build?

 

[RYU]

For a race car, single. For a street car, twin.

Yet, i'm finally pretty happy with the CTSC so i'll be on the blower for the foreseeable future.

You might want to PM Coz. He's been tracking a single turbo for a few years now and last I spoke with him, he's switching to SC.

 

[toomanymodz]

My 87 Grand National is a stroker 4.0L V6 and I run a single turbo. It runs high 10's on straight pump gas. Having an automatic is the way to go with a turbo setup. With a 5 or 6 speed NSX, I would recommend going with a SC instead. Turbos always have a lag, and with a manual transmission, you'll have the 'rubber band' effect.

 

[TURBO2GO]

Dimer is already supercharged and his post isn't asking to go into the big SC/Turbo debate that prime is littered with. The question is single or twin. Dimer check your facebook PM.

 

[GSV NSX]

If you want to have power and a strong turbo go single. It also looks better. EVERYONE who has lots of power knows to go single. The rush feels so good. How do I know ? Ask the T51r spl Supra in my driveway She makes 790 wheel on pump gas. But listen power aside , since it has a little more lag you're not always wasting lots of gas of you're driving around town. Small twins will kill you. Plus turbo lag in racing doesn't exist , there's anti lag. And I don't know of anyone who races with their car under 3500 rpms

 

[Dimer]

Dimer is already supercharged and his post isn't asking to go into the big SC/Turbo debate that prime is littered with. The question is single or twin. Dimer check your facebook PM.

Checked my FB, nothing new in my inbox

 

[RYU]

oh, one more thing I like about SC. Overboosting is virtually impossible.

Agree on the above comments from GSV.

Let us know what decide to go with Dimer.

 

[BATMANs]

When I spoke to Coz on why he is going from Turbo to Supercharger is that when the boost on the Turbo suddenly kicks in it shocks his tranny and breaks it.

 

[TURBO2GO]

When I spoke to Coz on why he is going from Turbo to Supercharger is that when the boost on the Turbo suddenly kicks in it shocks his tranny and breaks it.

That sounds more like a turbo sizing and tuning issue to me.

 

[RYU]

That sounds more like a turbo sizing and tuning issue to me.

its the sound of 500+ whp. anything over 400 and shit just starts breaking.

- - - Updated - - -

When I spoke to Coz on why he is going from Turbo to Supercharger is that when the boost on the Turbo suddenly kicks in it shocks his tranny and breaks it.

and SC is just easier to drive at the higher power levels. at our last track event he also mentioned to me that I would be able to get on the gas out of a turn and accelerate faster and pull away before his boost kicks in and he'd catch up. then again, I don't know if he was just trying to make me feel better because Coz is FAST.

(sorry for the OT Dimer. Back on topic!)

 

[Valhalla]

Once you get north of 400+ rwhp, things start to break. A single turbo that will produce that much added horsepower will have an inherent boost lag. The trick is to size the turbo and boost levels so that a) your boost comes at a level that is predictable and b) is linear in delivery.

 

[RYU]

Once you get north of 400+ rwhp, things start to break. A single turbo that will produce that much added horsepower will have an inherent boost lag. The trick is to size the turbo and boost levels so that a) your boost comes at a level that is predictable and b) is linear in delivery.

or get variable vane turbos, which is just cheating!

 

[TURBO2GO]

PM'ed you Dimer.

 

[RYU]

^^ He PM'ed you about DDozier's twin turbo setup. Which is pretty cool! haha

 

[NetViper]

Having been in several turbo NSX, I don't see a need for twin turbo if you use a properly sized turbo and are looking for 400-500HP.

 

[illwillem]

For track? NA all the way!

 

[DDozier]

There are many things to consider when tracking a car but one of the main things to think about is power delivery. Anyone utilizing 400whp on the track in a NSX will have the potential to be very fast. Much more than 400whp and you now have the power to go very quick in the corners and defend against the 600hp vetts and vipers in the straights.

Power delivery in a Positive Displacement SC is very linear, they are easier to tune, and are very predictable on varying throttle inputs. Those are the PROs the CONs are well noted on this site but the biggy is heat, and lots of it, with very few options for getting it out of the system. If you plan on tracking your car a lot heat is the biggest factor in power and reliability you are going to face. You need to take steps to cool the IAT's, ECT, Oil temp

Power delivery in a single turbo is less linear, it will make higher peak HP and most likely higher TQ at almost every RPM once spooled. The main challenge is to make sure the turbo can spool quick enough to be at peak boost and stable before VTec. Big single turbos in general are more of a challenge to tune as well over the SC, but smaller twins act much more like an SC in lower and mid RPM range, for this reason alone I chose to go twin. You will spend much less time in transitions between boost and no boost due to the quick spooling ability of twins, factor in Variable Vane Turbos and in my mind there is no advantage at all in the SC. Turbos are easier to cool the IATs, this is key to keeping the car cooler and helping to keep ECTs low and OIL temps low. Turbos place the added system weight at or below the cars center of gravity, they have less or equal maintenance, and are much easier to change power levels to suit any given track or track condition. What are you going to do in your 500whp SC when it rains, with a turbo you can flip a switch or turn a knob and be at 300whp or what if you can not get around that guy in the vette on every lap driving around with you front bumper attached to his rear bumper for 80% of a lap, then on the long main straight he opens up 5+ car lengths on you. Wouldn’t it be cool to have a car that will increase boost based on the gear your in, or a button on the wheel you can push to pass. All of this is not only possible with a turbo it is easy to implement, it can be very complicated to do with an SC.

The Turbo for me was the logical choice, Twin Variable Vane Turbos was the best choice. I have been tracking my Twin Turbo setup for two years and 25+ track days. I have had three NSX and tracked them all, in NA, SC and now Turbos. I can tell you my twins are as linear as the CTSC are much easier to maintain and service then the CTSC car, are really the best compromise between track and street driving. I could not be happier and I would guess that many of these same characteristics would hold true for just about any properly sized and tuned Twin Turbo system on a NSX.

Lots to think about and cost is another factor in the single vs twin designs. All twins are going to cost more than a single and Variable Vane twins is going to be the most expensive of all the systems.

Dave

 

[RYU]

Just a small tid bit to add. I was ready to ditch my CTSC all together because of the heatsoak. It would easily get into 90-100C at the track. I then added Water Injection and it was amazing at the last track event. Temps ever got above 55C. Still aiming for sub 40C and will get there if it's below 100F ambient. Also trying a new phenolic insulation spacer I helped Adnan develop for the CTSC.

With a turbo it's much easier to plumb the cooling and Dave's intercooler setup is super super trick. I love that setup Dave!

 

[DDozier]

With a turbo it's much easier to plumb the cooling and Dave's intercooler setup is super super trick. I love that setup Dave!

Testing will be complete after this track season, then it is time to sell these parts I have developed and retire my baby back to the mean streets. I am seriously looking at the Superlite SL-C, if I do not go with a Sportsracer as a full time track car.

Dave

 

[Coz]

With a 35R it's not the size of the turbo or the HP, it's the torq that break gearboxes.
I'm sitting at 601 rwhp with 488 lbs of torq @ 17lbs of boost, the NSX gearbox was not made to handle such torq.
My second map is 565 rwhp and 423 lbs of torq at 14 lbs of boost, while a little easier on the gearbox, I still have broken 2nd gear once, 3rd gear twice and shaved all the teeth of my ring and pinion gear.
All times it was on track when the gearbox let go under full power coming off an apex.

What I find with the turbo and the HP/Torq I run on track is it's a guessing game how soon you can go to full throttle coming to and off the apex's trying to time the lag out. Too soon the rear end wants to come around and it becomes a major handful, too late, your slow off the apex. Time it right and it's a rocket and things start to break. It can be a very inconsistent situation depending on the track and layouts. Short tight tracks are even tougher to time things correctly with a turbo. Now if your running less boost and less HP/Torq, then it would probably not be as big an issue.

What I have always liked about SC's is the fact the power delivery is very linear all the way through the power band. Its consistent, put your foot to the gas and go, no wait time or timing involved. Much easier to modulate the throttle and throttle steer as well.

The start of next years season, I am going to be running a SC that Nick at Applied Motorsports has developed and we've been testing. I will run somewhere between 525 and 550 rwhp, but the torq will be considerable less and easier on the gearbox, and I know from experience it will be easier to drive, easier to control and easier to predict under go fast track competition.

 

[TURBO2GO]

I've looked closely at the dyno sheets posted by Dave and compared it to various supercharger systems. I've compared IAT's, boost, and torque numbers. Dave is building THE most power, with the highest torque, with the least boost, and the lowest IAT's. That simply is saying that his setup is the most efficient, and is turning more gasoline into power and less into heat. I think this is the kind of thing you want to look for rather than just the highest numbers. His engine is producing more power with less stress. That adds longevity. Something to keep in mind.

 

[cptnsx]

Superchargers are the best option for a stock engine since you can't go far over 400rwhp and most turbos really show there efficiency above 8 psi (and then far above 400rwhp). Most of the muscle car guys are running superchargers with many of them PD superchargers. They have figured out many of the problems that we are having especially with heat soak (which is the only real negative to the PDs).

Upgraded heat exchangers with many of them in dual pass configuration with small fans and bigger pumps. There is space to run a bigger heat exchangers for the intercooled superchargers as well as some slim fans. The super chiller which taps the A/C to cool the intercooler water is also an option. The muscle car guys are running these things on the street, the drag strip, and the track. They have the data to back it up plus the number of installs to show repeatability We don't need to reinvent the wheel here just a vendor to step up to the plate.

 

[TURBO2GO]

Superchargers are the best option for a stock engine since you can't go far over 400rwhp and most turbos really show there efficiency above 8 psi (and then far above 400rwhp). Most of the muscle car guys are running superchargers with many of them PD superchargers. They have figured out many of the problems that we are having especially with heat soak (which is the only real negative to the PDs).

Upgraded heat exchangers with many of them in dual pass configuration with small fans and bigger pumps. There is space to run a bigger heat exchangers for the intercooled superchargers as well as some slim fans. The super chiller which taps the A/C to cool the intercooler water is also an option. The muscle car guys are running these things on the street, the drag strip, and the track. They have the data to back it up plus the number of installs to show repeatability We don't need to reinvent the wheel here just a vendor to step up to the plate.

I have to disagree with you somewhat. The muscle car guys drag race. That is very different than road racing as it is a 10 second run not a 20-30 minute outing. The super chiller for example seems to be ineffective for any prolonged period of time. There is room for bigger heat exchangers but the heat exchanger is not the problem on heat soak. Fanning it more also will not help because that is not where the problem lies.

I think I have spent maybe 1000 hours and read 1000 posts on this subject. My personal opinion remains:

1) on a stock motor for someone that wants a mild upgrade in power without the extra headaches and cost of going that next step (which is huge), the basic Comptech (CT Engineering) supercharger is absolutely the best solution. Mild, safe, cost effective, 50 state legal. And on the street, heat soak is not an issue with it.

2) The next step beyond is immediately what Dave Dozier has going. It is the most efficient, most well designed turbo kit I have seen. There are some limits with this kit if you want to go to the MEGA power territory. Well above 600 HP. Up to that point, between the 330-350 of a CTSC and say 700HP, I do not know of a better system.

 

[Coz]

So when are you going to install Dave's system and what Competition/Club Series will you be racing in ?

I have to disagree with you somewhat. The muscle car guys drag race. That is very different than road racing as it is a 10 second run not a 20-30 minute outing. The super chiller for example seems to be ineffective for any prolonged period of time. There is room for bigger heat exchangers but the heat exchanger is not the problem on heat soak. Fanning it more also will not help because that is not where the problem lies.

I think I have spent maybe 1000 hours and read 1000 posts on this subject. My personal opinion remains:

1) on a stock motor for someone that wants a mild upgrade in power without the extra headaches and cost of going that next step (which is huge), the basic Comptech (CT Engineering) supercharger is absolutely the best solution. Mild, safe, cost effective, 50 state legal. And on the street, heat soak is not an issue with it.

2) The next step beyond is immediately what Dave Dozier has going. It is the most efficient, most well designed turbo kit I have seen. There are some limits with this kit if you want to go to the MEGA power territory. Well above 600 HP. Up to that point, between the 330-350 of a CTSC and say 700HP, I do not know of a better system.

 

[TURBO2GO]

So when are you going to install Dave's system and what Competition/Club Series will you be racing in ?

Dave's system is in development and still not exactly for sale. But I have been setting some funds aside for it for a while, if that is the direction I decide to go. I don't have an interest in wheel to wheel racing. Jim it's hard to tell over the internet but if you are being sarcastic because I said I think that is the best system when you clearly feel you want to go supercharged, I don't want you to take offense to what I have said. You are building a race motor that suits you, and every individual has separate needs. I am saying from an engineering standpoint, in between the readily available kits (not something custom), this system is the most well thought-out that I have seen.