What is the Comptech Supercharger?
It is a Roots-type supercharger kit for the Acura RSX Type-S. The kit contains the compressor, manifold, pulleys, tensioners, assorted hardware and a k-100 upgrade to your ECU. Click here to see what the CTSC looks like.
Who is Comptech? Do they know what they're doing?
Comptech is probably as close to a factory-sponsored performance shop as Acura and Honda have. For over 20 years Comptech has been building and racing Honda performance products, including Indy 500 race cars. Comptech is located in El Dorado Hills, California. They make supercharger kits for many Honda and Acura lines.
How much does the kit cost?
US$3,595 for the base kit including the k-100 ECU upgrade and flash. Different pricing is available for those who already have the K-Pro.
What performance gains will I get?
The base CTSC kit will add between 40 and 50 wheel horsepower, depending whether your start from stock or already have some modifications. My car, which already had a street header, CAI, catback and K-Pro went from 192 to 232. Overall, people who install the base kit report anywhere between 225 and 235 whp. Click here to see dyno comparison stock NA to street CTSC.
Is the CTSC kit street legal?
The base kit has received CARB approval and is therefore completely street-legal anywhere. CARB generally requires that no emissions-related items have been changed, and that consumers cannot change settings. This is why the street CTSC kit uses the stock 310cc fuel injectors and the k-100 ECU upgrade (unlike the K-Pro, the k-100 cannot be tuned by users).
Will my gas mileage go down with the CTSC?
Very little. My car had a lifetime average of 26.5 miles per gallon (over 10,000 miles). With the base CTSC kit, mileage decreased by just over one mile per gallon to 25.5 mpg. As always, mileage varies depending on how often you're boosting.
Will there be additional stress on my car?
Any performance mod adds stress. However, the CTSC system has a bypass valve that cuts out the compressor when no boost is required, which means that 95-98% of the time you're not boosting and not adding stress to the engine. The compressor uses less than 1/3 of 1 hp when cruising at 60 mph.
How does this bypass valve work?
It is a butterfly valve like the one in the throttle body (see picture). The default is closed. When vacuum is high (idle-cruising) an actuator opens the bypass valve so that intake air bypasses the compressor. When accelerating, vacuum decreases and the bypass valve instantly closes. Intake air now goes through the compressor, building boost.
I thought a supercharger needs larger injectors.
More power means more fuel means larger injectors. However, in order to pass CARB, the base kit had to use the stock injectors. They run out of capacity at between 7100 and 7500 rpm. This is why the CTSC base kit has a 7900 rpm redline. Extensive datalogs have shown that even though the injectors are at 100% dutycycle, the air-fuel ratio remains within normal range even at redline.
What's the deal with larger injectors, anyway?
Unfortunately, almost every car company uses different injector plugs. The most common third party injectors for the K-Series, RC Engineering injectors, have a different plug and need adapter clips soldered on. Comptech does not want to cut the wires and solder on adapters. Power Enterprises makes 510cc injectors that fit, but they are expensive. Comptech has been experimenting with less expensive alternatives. They tested 470cc Marelli injectors that could be used with a small alteration to the connector. They also tested modified stock injectors and other modified Honda injectors that can flow up to 530cc (stock is 310cc). Bottomline: if you use K-Pro and install your own pulleys and injectors, you can use anything you want. If you want official upgrades from Comptech, they will likely have a solution that costs less and is plug-and-play.
Can I install the kit myself?
You can, but I do not recommend it and Comptech does not recommend it. There is very little room to work with, and it is crucial to get pulleys and tensioners done just right. It's better to pay a qualified installler. That way, if something goes wrong, you can go back and have it fixed.
What does the CTSC sound like?
It's pretty quiet. Much quieter, actually, than a NA card with a SRI or CAI. Even if you have a SRI or CAI, the compressor will muffle the sound. What you hear when you step on it is an urgent, mechanical whine as you accelerate.
How much boost does the CTSC make?
The base kit makes up to just under 5 psi of boost. The "Stage 2" upgrade increases boost by using a smaller compressor pulley to make the compressor turn faster. The base kit uses a 3.8-inch pulley. Stage 2 uses a 3.6-inch pulley which increases boost to about 6 psi. Comptech also has 3.3-inch (about 8 psi) and 3.1-inch pulleys (about 10 psi).
230 whp is nice, but I want more!
Then you need to get larger injectors and a smaller blower pulley. Comptech's "Stage 2" upgrade consists of a reflash, a 3.6-inch pulley, and a new set of injectors that flows about 530cc. In my car, that combination makes 258 whp, with the cat in place. Comptech does not want to solder or crimp injector wires and the Stage 2 injectors are drop-in replacements for the Honda stock injectors. Click here to see dyno comparison between CTSC base and Stage 2.
If you have the K-Pro, you can do your own "Stage 2" (or better) by buying the 3.6 or 3.3-inch pulley and retuning the calibration. You'll need at least 500cc injectors, and you can use RC injectors if you don't mind soldering.
260 whp is nice, but I still want more.
The 3.3-inch pulley will make about 275+ whp (for that you either need injectors modified by Comptech, or RC 550 or 650 injectors if you don't mind cutting and crimping wires), and Comptech will release an aftercooler kit that will probably add another 15 whp or so. Also, special SC cams, race headers, etc., can push the performance level even higher.
Can I use the larger K24 crank pulley for more boost?
The k24 pulley will increase boost by one or two psi, but according to one tester, there is a danger that the groove in the crankshaft for the key is starting to wear to one side. We recommend against using the k24 pulley.
I want to break into the 12s. Can I do that with the CTSC?
Yes, OsideJimc ran a 12.96 in the quarter with a 9-psi CTSC on Hoosiers, and even faster with a 10-psi configuration that used race gas and IPS cams.
Can my engine handle high boost?
The k20 series is a strong engine, but experts suggest not to go past about 9.5 psi on stock pistons as the ring lands can't handle prolonged stress. Joe McCarthy at prototyperacing.com recommends CP and JE boost pistons and Carrillo, Cunningham or Crower rods. He says, "Don't use anything made in China, like Eagle, Scat, or Import Builders; it's false economy putting cheap rods into an engine."
How do I replace the blower pulley?
Remove the outer portion of the belt tensioner. Then move the power steering reservoir out of the way (remove two bolts). Use a 12-inch crescent wrench to hold the blower pulley and an 18-mm socket to remove the pulley nut.
If a belt breaks, how do I replace it? (thank you, OsideJim!)
1. Release tension using 12mm socket
2. Pop P/S resivoir out of bracket
3. Remove 2x 12mm bolts holding tensioner in place, remove tensioner
4. Using 14mm wrench remove bracket holding fixed idler
5. Jack up right front of car, remove tire, then remove 2 plastic clips holding splash guard in place.
6. Remove belt, feed new belt from above, then route around pulleys starting from below (see step 30 of install instructions for details Install Instructions ([url]http://www.comptechusa.com/instructions/RSX%20S%20Supercharger2005.pdf) ).
7. Re-install fixed idler, being careful to route belt properly.
8. Re-install tensioner arm but do not completely tighten bolts, make sure lip on brass thingie on the end of the tensioner is hooked on bottom of fixed idler barcket, adjust tension, then finish tightening tensioner mounting bolts.
9. Double check belt routing and installation then re-install splash guard and wheel.
10. Drive it 50 miles and re-adjust tension.
11. Repeat step 10
Click for belt routing picture
Have there been problems with the CTSC?
Comptech's initial tensioner design was prone to breaking, so Comptech designed a new one and sent a new tensioner/pulley kit, free of charge, to all owners (if you didn't get one, call Comptech with blower serial number). There have also been a number of cases where the pulley sheared off the blower assembly. Comptech redesigned the compressor snout and is replacing it on all units. Further, installation requires bending the powersteering line a bit, and that has caused some breaks.
I heard the CTSC, if installed by Acura, will not void my warranty.
Officially, Comptech's warranty only covers the base Comptech Supercharger kit, but no engine or other failures that might possibly have been caused by the CTSC. However, Comptech and Acura dealers have been known to be very accommodating in working with customers on such cases.
How does it feel to drive with the CTSC?
Wonderful. Around town a street CTSC car idles and drives just like stock. But when you step on it, there is much more power and torque. In fact, you can no longer floor the accelerator in 1st gear as you get wheel spin and hop, and there is enough power for wheel spin in second. Bottomline: a CTSC is much faster than stock, but launching it will require a new technique. Stickier tires might help a lot.
I don't see a CTSC calibration for the K-Pro.
Hondata created the k-100 calibration for the CTSC on Comptech's dyno. However, in order not to jeopardize the CARB approval process, Comptech cannot release that calibration. Those who already have the K-Pro and want the CTSC should simply use the JRSC calibration. The two systems are similar.
Can I buy the CTSC from ClubRSX?
Yes, on June 30, 2005, ClubRSX became an official Comptech dealer. When you make your purchasing decision, consider how much free support and information on the CTSC you get here on the ClubRSX forums.
Created: April 26, 2005 by conradb212
Last updated: September 15, 2005
Questions? Email me at conradb212@mac.com
