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Twin screw/CTSC intake question

Joined
8 March 2006
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Location
Boston
Before I go spending more money on a fancy intake, can someone tell me this:

When a car has a twin screw, does intake restriction become more or less critical? Specifically, if there IS a slight bottleneck, does a twin screw type SC care more, or less? A part of me says more air is going in VS. NA, so the horsepower loss due to restriction would be greater. Another part says "it won't matter as much because the SC will suck it in with greater force than NA and compress it anyway".

There is a lot of talk now about BBTB's and air intakes, and some say the factory box and filter, and the factory throttle body are as good as anything aftermarket. What about on a CTSC engine?
 
Call Shad this has been discussed in great length.

In short don't wast your money on the 90mm Nissan intake or the 5mm gain modded on the stock one making it ~80mm.
 
Before I go spending more money on a fancy intake, can someone tell me this:

When a car has a twin screw, does intake restriction become more or less critical? Specifically, if there IS a slight bottleneck, does a twin screw type SC care more, or less? A part of me says more air is going in VS. NA, so the horsepower loss due to restriction would be greater. Another part says "it won't matter as much because the SC will suck it in with greater force than NA and compress it anyway".

There is a lot of talk now about BBTB's and air intakes, and some say the factory box and filter, and the factory throttle body are as good as anything aftermarket. What about on a CTSC engine?

Are you talking about the intake manifold, the throttle body or the intake into the blower housing?

Each has it's own issues and benefits. The real question is where you want to end up, HP and $? Once you decide, then it is time to make a plan. What works at 400HP, may not be enough for 700HP...etc. Once again, it really comes down to how much $ you want to throw around. There are better options out there than the stock set up, probably at any HP you desire. But is it worth $10K for a custom manifold when you can just push more boost pressure? There are trade offs in every set up, Honda did a good job making a set up which is very drivable and makes good power, can you do better for an all around driver? I doubt it. You can do better for a 'make lots of power' set up, if you are willing to accept the compromises.
 
I think Dave is asking about a simple intake like the cantrel or downforce scoop. The stock set up is a joke when you look at it. Ditch it for the big scoop. There are other benefits outside of shear power. I love mine. I'd tgen move to a uni filter, but you could keep the paper one if you wanted.
 
I was wondering how a CTSC affects the "bottleneck" at the actual air intake box/filter and then the throttle body. There is a lot of argument about the benefits of a big bore throttle body on NA... same arguments about the stock airbox versus aftermarket. Some say there is some gain and some say there is none. But with a CTSC you are moving A LOT more air. So I would think that changes things. I think Chris at SOS did a dyno test on a BBTB with a CTSC'd car and got 8 or 9 HP increase. I am just wondering (and I wish people would speak freely) about those results. A better airbox and BBTB are relatively small investments if they will make a difference on a CTSC'd motor. The intake manifold is a larger investment and not readily available, I was wondering about the smaller cheaper upgrades. I know this subject has been brought up before but I just didn't really get any sort of solid answer. Maybe no one really knows? I am intersted in hearing opinions as well.
 
I have the uni filter and the cantrell AIS on my car, I dont have any dyno proof that with the CTSC it gains any horsepower but for sure it does sound very nice!
 
Dave, your dyno isnt different from those of us who have the scoops. I would get a scoop, but I dont think that your SC is having a tough time getting the air through that rediculus snorkel the car comes stock with.
 
Already have the AIS/Uni Dave. No one other than SOS has done a direct dyno on a CTSC car to see if a BBTB makes any gains. Its $250.
 
Turbo,
I don't know why you keep posting for OPINIONS when you can call the Guy that designed your CTSC. I just talked with Shad an hour ago :confused:

If anybody else got to spend the millions of dollars from Acura/Honda for development I could point you to them but he's the man for your SC.

If you are still running an Autorotor on stock internals without addressing the boost spike problem.......YOU ARE AT THE LIMIT NOW.

We have an idea of how to limit your boost and any time now get a New product out but you must be pushing ~+8psi (W/ belt slip) and you want MORE air :eek:

Save up for some NEW pistons.
 
Say what Jeff - what boost spike issue. The only issue Ive heard about with the autorotor is running it too cold without high octane in it. Ive heard of zero issues with the charger as long as it is good and hot and timing is pulled back.

What are you speaking of?
 
.........Each has it's own issues and benefits. The real question is where you want to end up, HP and $? Once you decide, then it is time to make a plan. What works at 400HP, may not be enough for 700HP...etc..............There are trade offs in every set up, Honda did a good job making a set up which is very drivable and makes good power, can you do better for an all around driver? I doubt it. You can do better for a 'make lots of power' set up, if you are willing to accept the compromises.

He's talking about the use of a stock computer W/ piggy back fuel control or going all out.


YES, Many people are seeing 8+psi stock Autorotor setup and on a stock internal motor that's max for the compression and bottom end (also a debate).

But simply think of the overall picture. Your motor is a pump and air / fuel make it turn. Now add more fuel = runs like crap RICH. Now add more AIR but not more fuel = lean out and BANG rings/pistons or worse :eek:

I know this is simplifying things but Turbo (not picking on you man) has a nice '05 W/ open headers and exhaust running an Autorotor W/ stock computer. He wants MORE POWER and that's cool but remember Daves post about reliable DD it's just not going to happen.

For that power add an AEM ECU, larger injectors, bigger intake, smaller pulley, Daves CTSC block (for a non slipping belt), and tune.

Now it's a slippery slope..........I want more.......forged low comp. pistons, big cams, valves, and tune.

I WANT MORE
Shads 3.5L build, my billet mains, screw the SC and go turbo, BIGGER INJECTORS, and a bad ass tune. WOW... I'M at 700+HP :eek:

BTW: that last build just SHEDDED your clutch and now you have NO teeth on 2nd gear...............so add a rebuild on the trans W/ an OS Giken LSD.......and ON IT GOES :biggrin:
 
Max boost on my car on all dyno runs has been under 7 PSI. 6.7 something I am pretty sure. I don't have this mysterious "boost spike". My AF ratios have been perfect, a little on the rich (safe) side. I talked to Shad at length on the phone and he felt everything was in fine working order.

Still, I am considering the aftercooler, pump, injectors and AEM FIC. But that does add some level of complexity. I am actually very happy with the power of the car. I am not enough driver for what this car can do already, and I don't drag race (which I find extremely boring compared to road racing). I just was wondering if there is some bottlenecking now that could be easily relieved with a BBTB or different intake.

I am not saying if you gave me a Comptech 3.5L with the big whipple I would say no. :biggrin: I am completely sold on a twin screw SC for track use, their behavior is so much better FOR ME than any centrifugal SC or turbo car I have ever driven. My car ran flawless at Watkins Glen. The fact that on the straights I was staying right on a 997TT's tail was fantastic. I wish I had a video.
 
Sorry to interject. No spikes? :confused:

If you're only driving in the same temperatures and conditions I'd buy that.

A drop in temperature from early morning to mid-day in most US climates will cause you a spike one way or the other.

So how does the CTSC keep IAT steady under all weather conditions given it's placement and design? You've got my brain tickled.
 
Still, I am considering the aftercooler, pump, injectors and AEM FIC. But that does add some level of complexity. I am actually very happy with the power of the car. I am not enough driver for what this car can do already, and I don't drag race (which I find extremely boring compared to road racing). I just was wondering if there is some bottlenecking now that could be easily relieved with a BBTB or different intake.

This quote is like you are talking it over with yourself.

Look "I am considering the aftercooler, pump, injectors and AEM FIC" add the lines, water tank, and tune" that's a bunch of weight and work + $$$$.

Than "I am actually very happy with the power of the car." cool drive it maybe if you plan to Track the car more spend the money on suspension/breaks.

And "wondering if there is some bottlenecking now that could be easily relieved with a BBTB or different intake" adding all the complex parts and tune for the extra air won't matter as "I am not enough driver for what this car can do already" so to me your car runs great with little to no major maintenance/problems.

Time to go drive it and be happy. You have reached your goal :smile:
 
Dave just likes stuff. It has been a couple weeks since he bought something for the car

Dave, unless your objectives have changed from what they have been for a couple years, i would turn your attention to other parts of the car and away from the engine. Anything more there adds a massive PITA. You need TiDaves super stopping expensive brakes.

If you went to a faster speed, you would find that that 997tt would start to pull away. I'm right with them, new z06s, f430s until about 130mph at which point they start to pull. At 150mph theyre pulling nicely away.
 
Max boost on my car on all dyno runs has been under 7 PSI. 6.7 something I am pretty sure. I don't have this mysterious "boost spike".........

That's NOT possible unless this is true.

Sorry to interject. No spikes? :confused:

If you're only driving in the same temperatures and conditions.......

The CTSC or any boost will change W/ intake air temp. Your belt IS slipping at high RPM. You can get more consistent boost using TiDaves CT block (Ask Shad).

After you get your belt to stop slipping most have recorded ~8psi. You will pick up some HP by doing this but I would recommend getting the A/F checked to see if you NEED to up your fuel pressure (Shad can help you with this) to run safe.

The NEWER Autorotor you have now runs cooler and why CT NEVER recommended a different pulley for a Hi-BOOST KIT. Also W/ the new SC running on a stock motor I don't see any benefit adding a complex aftercooler, front mount IC, pump, tank, lines, and switch.

Running TiDaves car at THill W/ the big SC in 95+ degree heat only turning it on about half the time seeing little difference (but the car was running like crap than lost the front head on I5 but that's another story). I would think overkill on a street car unless you like having more crap to deal with... a independent cooling system W/ water, lines, switches, and now twice the maintenance......leaks :eek:
 
Dave just likes stuff. It has been a couple weeks since he bought something for the car


BINGO!!!


That's NOT possible unless this is true.

The CTSC or any boost will change W/ intake air temp. Your belt IS slipping at high RPM. You can get more consistent boost using TiDaves CT block (Ask Shad).

Well I pretty much drive the car when it is warm out. The car sits in the winter. The belt is probably slipping a bit. I bought titanium daves little block but didn't install it. I just have NEVER seen boost higher than 7 PSI on the car, cold or hot. For having no aftermarket engine management, I am really surprised at how consistent the AF ratios have been. Good advice however, thanks for the input.
 
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