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For the record re: Comptech camshafts

L_RAO

L_RAO

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18 November 2010
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Pasadena, CA
1. They are discontinued.
2. They are hard-welds, not regrinds.
3. They spec out at:

Intake: 256 degrees duration, and peak lift of 0.450" (11.43 mm), vs. 230/0.402" (10.20 mm) OEM
Exhaust: 251 degrees duration, and peak lift of 0.430" (10.92 mm), vs. 225/0.354" (9.00 mm) OEM
 
L_RAO said:
1. They are discontinued.
2. They are hard-welds, not regrinds.
3. They spec out at:

Intake: 256 degrees duration, and peak lift of 0.450" (11.43 mm), vs. 230/0.402" (10.20 mm) OEM
Exhaust: 251 degrees duration, and peak lift of 0.430" (10.92 mm), vs. 225/0.354" (9.00 mm) OEM
Click to expand...

two questions!

what valvetrain will you be using?

will you be using adj. cam gears to degree the cams or just run standard cam angles?
 
Valvetrain will be stock for now...no one at CTE seems to know who the contact is at Eibach anymore, therefore, we don't know what springs to use (since Eibach doesn't have it listed in their catalog). For now we will keep factory redline and see what the dyno tells us.

No on the adjustable cam gears...I couldn't find anyone who could dyno tune with the engine in the car (everyone wanted to do it on an engine dyno with the engine out of the car - that was too much $$$). I had Nick at Applied Motorsports simply install them at 0 (straight up). I know the Comptech cams gears are also about 50% lighter than OEM, but $1100 is a lot of money to spend just to save a few grams.

d_prada1 said:
two questions!

what valvetrain will you be using?

will you be using adj. cam gears to degree the cams or just run standard cam angles?
Click to expand...
 
L_RAO said:
Valvetrain will be stock for now...no one at CTE seems to know who the contact is at Eibach anymore, therefore, we don't know what springs to use (since Eibach doesn't have it listed in their catalog). For now we will keep factory redline and see what the dyno tells us.

No on the adjustable cam gears...I couldn't find anyone who could dyno tune with the engine in the car (everyone wanted to do it on an engine dyno with the engine out of the car - that was too much $$$). I had Nick at Applied Motorsports simply install them at 0 (straight up). I know the Comptech cams gears are also about 50% lighter than OEM, but $1100 is a lot of money to spend just to save a few grams.
Click to expand...

1100 for cam gears!! are they made from diamonds sheesh. I would save the money too (I was just talking in regards of degreeing the cams)

I picked up the exhaust gear for my k24 for 50 bucks on craigslist haha. I wish we had VTC on the nsx, that would open up a WORLD of power on our engines. I gained about 20HP up top on stock cams when i kept my cam angles at around 40 degrees till redline.


As for the springs I think you should be alright using the stock valve springs at stock redline. I was always scared into using them but i just used the factory dual valve springs on my rsx, with some stage 2 cams and never had any problems @9100

I am really looking forward to how much power you make. I want to do a similar build when i get back home!
 
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Well, Nick and I had a long discussion...and he thought the most pragmatic route was to simply drop the cams in.

No matter what we did on the valvesprings, whether it was go to an aftermarket spring or simply take the OEM springs and have them WPC treated, a change would have required to pull the heads off altogether, and at that point we're opening up a giant can of worms (12+ more hours of labor, might as well WPC treat the rocker shafts, upgrade LMAs, etc., etc.).

I've been looking for used cam gears for about 3 years now. To say that they don't come up very often would be an understatement!

d_prada1 said:
1100 for cam gears!! are they made from diamonds sheesh. I would save the money too (I was just talking in regards of degreeing the cams)

I picked up the exhaust gear for my k24 for 50 bucks on craigslist haha. I wish we had VTC on the nsx, that would open up a WORLD of power on our engines. I gained about 20HP up top on stock cams when i kept my cam angles at around 40 degrees till redline.


As for the springs I think you should be alright using the stock valve springs at stock redline. I was always scared into using them but i just used the factory dual valve springs on my rsx, with some stage 2 cams and never had any problems @9100

I am really looking forward to how much power you make. I want to do a similar build when i get back home!
Click to expand...
 
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L_RAO said:
Well, Nick and I had a long discussion...and he thought the most pragmatic route was to simply drop the cams in.

No matter what we did on the valvesprings, whether it was go to an aftermarket spring or simply take the OEM springs and have them WPC treated, a change would have required to pull the heads off altogether, and at that point we're opening up a giant can of worms (12+ more hours of labor, might as well WPC treat the rocker shafts, upgrade LMAs, etc., etc.).

I've been looking for used cam gears for about 3 years now. To say that they don't come up very often would be an understatement!
Click to expand...

Why do you have to pull the heads off? no space?
 
L_RAO said:
I assume so; pulling off heads/changing valve springs is above my pay grade so I listened to what Nick had to say.
Click to expand...

Well it is easier to take the heads off. I have never tried on nsx valves but i have never pulled heads for a valve spring change. Just keep the cyclinder pressurized to keep the valves up and take it from there. It is a pain in the arse though.

Good Luck! ill be following!
 
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L_RAO said:
Valvetrain will be stock for now...no one at CTE seems to know who the contact is at Eibach anymore, therefore, we don't know what springs to use (since Eibach doesn't have it listed in their catalog). For now we will keep factory redline and see what the dyno tells us.
Click to expand...

Post #313 has the Eibach valve spring part number:
http://www.nsxprime.com/forum/showthread.php/154927-Semi-DIY-Mild-Engine-Build-for-FI/page13?p=1569375&viewfull=1#post1569375


I went through all of this when I was looking for aftermarket valvetrain on my build. For my OEM camshafts it just didn't make sense for the OEM lift and the mild pressure I'd have to overcome for FI.

Dave


EDIT: Thanks for posting the Comptech specs!

- - - Updated - - -

Page #5 of: http://performance-suspension.eibach.com/sites/devperformance-suspension.eibach.com/files/catalogs/evs-catalog.pdf
 
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Thanks - that is very useful information.

I'm having a hard time finding out spring rates for the H22 Type S...the Eibachs seem a little stiff, I'm wondering if the Type S springs would be an adequate substitute.

Mac Attack said:
Post #313 has the Eibach valve spring part number:
http://www.nsxprime.com/forum/showt...or-FI/page13?p=1569375&viewfull=1#post1569375


I went through all of this when I was looking for aftermarket valvetrain on my build. For my OEM camshafts it just didn't make sense for the OEM lift and the mild pressure I'd have to overcome for FI.

Dave


EDIT: Thanks for posting the Comptech specs!

- - - Updated - - -

Page #5 of: http://performance-suspension.eibac...ion.eibach.com/files/catalogs/evs-catalog.pdf
Click to expand...
 
Not sure if this would qualify to make it into the Wiki, but here's the "cam card" from Comptech/CTE.
 

Attachments

  • NSX Cam Timing Card.pdf
    84.2 KB · Views: 66
If you haven't installed the camshafts yet, could you measure the VTEC / non-VTEC intake and exhaust cam lobes along the two axes in the picture?



With those eight measurements, we could confirm the lift specs Comptech published for the VTEC lobes and that the non-VTEC lobes still have the stock lift.
 
I won't have the cams out for a while, but I'll be sure to measure it when I do.

I had a question for you: How high do you rev your car to? Also, when you dyno'd your car, when (what RPM) did it make peak power at?

greenberet said:
If you haven't installed the camshafts yet, could you measure the VTEC / non-VTEC intake and exhaust cam lobes along the two axes in the picture?



With those eight measurements, we could confirm the lift specs Comptech published for the VTEC lobes and that the non-VTEC lobes still have the stock lift.
Click to expand...
 
When I had Autothority custom-program a chip for my PGM-FI, I asked them to leave the rev limit stock for the sake of engine longevity. With their chip, the fuel cutoff is just past an indicated 8000 rpm on the tachometer.

I haven’t had my NSX on a dyno for a while but the last time I did, it seems to have produced peak hp at about 7500 rpm and the power barely fell from there up to the fuel cutoff.
 
Thanks.

I'm in a little bit of a quandary here: on one hand my car recently made peak power at 8000 (because that's what the limiter was set to) and it kept climbing. So, there's probably more power with more RPMs.

However, I have 2 areas of concern at this point: the valvesprings and the oil pump gear.

For now I'm just going to enjoy the car as is.
 
When Comptech worked on my cylinder heads, they increased the depth of the valve spring pockets a bit so that the OEM springs wouldn't bind when used with their high-lift camshafts. Later, they started selling valve springs themselves and stopped offering that modification. Just something to keep in mind if you want to use Comptech camshafts with OEM valve springs.
 
That is interesting that they used to do that, because I have a hard time imagining that the OEM valvesprings would bind at 0.290" lift (at the cam, x 1.55 rocker ratio to get 0.450" at the valve).

I asked CTE about the oil pump gear issue and life above 8000 RPM, here was their reply:

Loc,

I spoke to Doug about oil pump gears and he said that it’s not so much RPM related. He contends it’s more continual high RPM or hard driving.

Please let me know if you have any further questions.

Thank you,

Nate Haines
CT Engineering
 
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If they don't bind, maybe Comptech didn't want the OEM valve springs to compress too far for stress reasons or something like that. When Comptech started selling valve springs I called them up to ask whether I should buy a set. They said no, there was no need. They started selling those springs so that they could stop modifying the pockets in the cylinder heads. It's a lot easier to install new springs rather than remove the cylinder heads and ship them to Sacramento for modification.

Edit:
L_RAO said:
That is interesting that they used to do that, because I have a hard time imagining that the OEM valvesprings would bind at 0.290" lift (at the cam, x 1.55 rocker ratio to get 0.450" at the valve).
Click to expand...
Maybe Science of Speed could shed some light on the issue. They state that their camshafts, which have even less lift than Comptech's, also require the use of non-OEM valve springs.
 
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What was your torque doing at 8000? Still relatively flat, or was it starting to fall off?

L_RAO said:
Thanks.

I'm in a little bit of a quandary here: on one hand my car recently made peak power at 8000 (because that's what the limiter was set to) and it kept climbing. So, there's probably more power with more RPMs.

However, I have 2 areas of concern at this point: the valvesprings and the oil pump gear.

For now I'm just going to enjoy the car as is.
Click to expand...
 
Has anyone tried the TODA valve springs, they say they are designed to work with their cams which do 12.0mm of lift. They are pricey but if they are designed around that 12.0mm lift number is it a safer bet than buying a new set of OEM springs?
 

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