Upgrade: Comptech Supercharger Pulley

[Scott Howard]

I have heard from Comptech and a few others that you can use an AP2 pulley to get a few more lb's of boost or you can go up so far (boost wise) with a new pulley on the factory fuel system.

If I get a wideband (to monitor) and get a pulley that's 2-3Psi higher via AP2 pulley or after market, how safe is that? (even though being boosted is not safe to begin with) :)

Or, what's the highest Psi I can go with the stock fuel system and what came with kit?

-Stock Comptech Kit
-I have the after-cooler too

I still don't have a header or Test Pipe yet, I just want to add some more pep to the S2000. lol

[repiv]

AP1 Comptechs have been commonly run with AP2 pulleys. This was the first "trick" that was done when Comptech came out with their aftercooler. The smaller pulley more than compensated for the loss of boost pressure as a result of the cooler.
I think you can go as high as 8 to 9 psi on the stock fuel system. As you approach 9 and above, you will need more than what Comptech gives you. You'll need a way to change timing a bit for safety and you need to be able to adjust fuel better.
Going from the stock AP1 pulley to the AP2 will net you about 1.5 psi. You are probably running about 6 to 6.5 psi stock now (with intercooler). The one example I personally witnessed where the smaller pulley was put on, the Comptech fuel management unit had to be turned up 3 full turns to bump up the fuel pressure. Before that, it started to run a bit lean. This was as the Comptech factory near Sacramento.
Each car is different and you need to monitor the A/F throughout the rev band and adjust the fuel pressure accordingly. Remember that the adjustment can only go so far. It has a very limited range of affect on the fuel pressure.

[Stratocaster]

Scott

You really should get your car tuned by something that knows how to tune it. On a Dyno, testing A/F. Huy at Inline performance did a great job on my car. He is on the Betlway and Clay rd.

[hecash]

Before the AP2 came out, I got a smaller impeller drive pulley made by ASP. They did the calculations for the new design from my measurements and pressure readings on my Comptech kit. I wanted 7.75 psi at 8,000 rpm and that's what they gave me. I added water injection aftercooling, boosted the rising rate fuel pressure regulator to cap out at 70 psi to further overdrive the stock injectors and drove it that way for about 40,000 miles and 30-40 track days.

I think drop-in 440 cc injectors are available from Kehin. Using those would allow you to leave the fuel pressure regulator cap at 62 psi which was the way Comptech shipped it.

[Scott Howard]

Scott

You really should get your car tuned by something that knows how to tune it. On a Dyno, testing A/F. Huy at Inline performance did a great job on my car. He is on the Betlway and Clay rd.

Huy is the one who tuned my car initially :rolleyes:
-and that's when he decided to pick up his phone.....

[Stratocaster]

Huy is the one who tuned my car initially :rolleyes:
-and that's when he decided to pick up his phone.....

Explain, pick up the phone?

[Doctor Mugen]

Explain, pick up the phone?

He's a little hard to reach on the phone sometimes. I just swing by his shop when I had questions (of course, I was working in La Porte at the time and his shop was nearby in Channelview).

[Stratocaster]

I called on Wednesday, and I got a call back within an hour. We scheduled a time on Saturday. We trailered the car there. He called me as I was looking in his shops windows ( he said after 2, and we got there at 2:45). I called him back, and he showed up 10 mins later.

All in all the event was painless and he clearly knew how to tune my AEM EMS.

[Jerome]

After a few months, I had the AP2 pulley installed on my AP1 (Comptech S/C & A/C) and what is said above is true. A/F mix needed to be enriched and I get 6.5 psi (at intake manifold) at 8,800 rpm. I understand the reason that Comptech did not recommend (or continue warranty) with the AP2 pulley on AP1 is that they did not get smog approval for that application on that engine. With the AP2 pulley, the boost starts at lower rpm and improves performance across the power band.

Jerome
NW Arkansas

[repiv]

I get 6.5 psi (at intake manifold) at 8,800 rpm.
Jerome, that seems a bit on the low side. I would have expected perhaps 7.5 psi or thereabouts. My friend's set-up with A/C and AP2 pulley dynoed about 280 whp at Comptech's facility.

[Scott Howard]

Ordered AEM Wideband

[repiv]

Ordered AEM Wideband
Then you might find this useful:
http://forums.s2kca.com/showthread.php?t=15947

[Scott Howard]

Then you might find this useful:
http://forums.s2kca.com/showthread.php?t=15947

Awesome, Thanks! :thumbsup:

[Jerome]

Dave, My '02 S was dyno tested and tuned two times. Once with AP1 pulley and once with AP2 pulley. Both dyno tests (on same dyno) were at about 100 feet elevation (NW Houston, TX) with air temps in high 80's. Both tests were done with completely stock exhaust system (no test pipe) and using 93 octane gas. The AP2 pulley gave 295 rwhp at 8,800 rpm. I have since removed the stock cat and installed a new Berk HFC. I believe (seat of pants) that the car now has 305-307 rwhp. I hope to get new dyno numbers before spring.

Jerome
NW Arkansas

[repiv]

Dave, My '02 S was dyno tested and tuned two times. Once with AP1 pulley and once with AP2 pulley. Both dyno tests (on same dyno) were at about 100 feet elevation (NW Houston, TX) with air temps in high 80's. Both tests were done with completely stock exhaust system (no test pipe) and using 93 octane gas. The AP2 pulley gave 295 rwhp at 8,800 rpm. I have since removed the stock cat and installed a new Berk HFC. I believe (seat of pants) that the car now has 305-307 rwhp. I hope to get new dyno numbers before spring.

Jerome
NW Arkansas
That's quite good for most Comptechs I've seen. Some pre-aftercooler kits could only pump out about 260 whp. These were back in the days when people really didn't know the limits of safe running for the kit and they erred on the side of caution. Plus, it was so new that they didn't know exactly what they needed to do to ensure a good, solid installation.

[darkside]

Huy is the one who tuned my car initially :rolleyes:
-and that's when he decided to pick up his phone.....


He does run a shop so is a little busy... and the easiest is to leave a message or just go to the shop. New location so its not far from you sir.

Oh and new dyno.:D