Z06Vette.com - Corvette Z06 Forum

drpipes · 10-08-2002, 12:12 PM

I took my car to RP Motorsport in Marietta this week and they tried to dyno tune my setup with existing components and were only able to get 390 RWHP and 360 RW torque. They are in the process of checking for any mechanical failure (ie springs) since my graph was not very clean even with a smoothing factor of 3.
Next, I am going to swap my Belanger headers for the TPIS. Xtreme has been very helpful in this swap and have once again lived up to their reputation as a great vendor on this site. Thanks again Xtreme!!!
I am concerned about the massive amount of lift with the Katech cam and will probably swap for a different grind with 918 springs. Then we will dyno tune this MF and get it where it is supposed to be.

I will keep you updated on this project from hell. Anyone thinking about a head/cam swap can PM me and I will be glad to tell you where I went wrong. It was truely painful!!!

**MikesZ06** · 10-08-2002, 12:17 PM

Do they think it might be the 941's, Doc?
Could they be the trouble source?

drpipes · 10-08-2002, 12:24 PM

I don' think so but they are going to check anyway. I think I will be a little more comfortable with lower lift and the 918's. This tuner has some tried and true cam grinds that will be easy enough to change when they are checking the cam install. The car has actually not been running bad, just not making the power I thought it would. The spring change is more for my comfort.

**MikesZ06** · 10-08-2002, 12:39 PM

Keep me informed, bro. God knows you deserve some more ponies after your ordeal

JBsZ06 · 10-08-2002, 12:43 PM

This is just a suggestion..if your in there...why not go with dual springs ?

Good luck and sometimes thistype of situation is unfortunately part of the modding process..

I"m sure in the end...you'll be very satisfied ..

We're all routing for you.

drpipes · 10-08-2002, 12:50 PM

I thought about that but it seems that it would require some machining of the head to do that wouldn't it?

RandyN · 10-08-2002, 01:15 PM

I've been reading along with your dilema and have re-frained from posting since I have not did a head and cam change on my Z. I don't know where your at with the project, but I'm sure that something is wrong. If I had to guess it is the cam. It has to be something in the cam timing. I would try having a new cam installed and have it degreed in. Or degree the old one in. All of the motors that I know of that the cams were degreed when installed and all OFF!

Every one, Crane, Comp. and whatever else.

You have changed alot of things at one time to try to diagnose with certainty. I would think that the heads are not the problem since they were most likely ported by a CNC machine. Remember:
No two cams are the same. NEVER. thats why they all have cam cards. Do you still have yours. I know of instances where brand new Comp rollers were sent back because they were so far off!

This is what I would do!

1. Check for a broken spring.
2. Degree cam in.
3. If ok Pull cam and send it back to get checked!

Your charactristics: Uneven power out put and low out put point to one thing. Cam timing. It is either to advanced or retarded causing poor performance. Start back tracking and eliminating the variables. You will get it. Hopefully sooner than later. It is not the tuning. somerthing is physically off!

Randy

drpipes · 10-08-2002, 01:28 PM

Thanks for everyone's input on this one. I think that you are right about the cam timing. The cam is a224/228 duration .581/.588 lift grind with 114* LAS according to the cam card. The lift is a lot more than most grinds I have seen posted here.

JBsZ06 · 10-08-2002, 01:38 PM

I think your on the right path..the only reason I mentioned the possiblity of going with dual springs while you were in there was for 3 hundred dollars? (a guess on my part) was because..I would want you to never have another issue..I'm sure the advice you have recieved from your tech matching the right single springs with the new cam..is a good way to go..

I'm sure your first path of fixing this issue is the right one..

I personally decided that if and when I ever do heads and cam..I'll spend the 3 hundred? extra to go dual springs..but in sooooo many cases its definitely not necessary.. ( I just have low tolerance for maintaince issues as unfortunately I live by murhpy's law..)

I could be wrong on the 3 hundred dollars so please excuse me if I underestimated the cost.

RandyN · 10-08-2002, 01:40 PM

Now, look at the cam card. It has numbers that a skilled car crafter could degree the cam in. It should have several numbers indicating when the valve opens and closes at both BTDC and TDC and at what degrees. This is incredibly critical and should only apply to the cam YOU have. Not others with the same lift. Cam cards are specific to each grind. 5 cams could all have the same p/n # from the same vendor and all still each have thier own card. No two cams are ever the same. They are kind of like people. That is why they all should be degreed in!

Randy

PS That cam profile is pretty basic and should work just fine!(when properly installed)