Dtownbrown

Yeah Iv decided to take the car to Kris @ KK performance in little rock. It's actually his old set up from a red c5 so he is familiar with it.

robert miller

I know Kris will get it worked out for you man. He put my new RHS build motor in my car, and did all the fab work on my fuel system and intercooler work, Plus rewired the car.

I will tell you this it will be done correct like it should be or he will not work on the car. It is hard to find someone like him and Shane.

BLOWNBLUEZ06

They're some real bad@sses for sure.
Especially for a pair Crackers!

robert miller

MVP'S ZO6

He had an 8.5" Balancer?

MVP'S ZO6

Nice Edit!!

Dtownbrown

Okay well. We got the boost issue figured out. It was the filter screen I had in front of the charger, I never would have thought that would cause the issue but lesson learned. But we came across another issue where the car stops gaining power after 5600rpms. It's making 19# @ 688rwhp 699 rwt. But after that it just falls off. Doesn't lose boost pressure and no belt slip. Fuel pressure is fine also. Kris suggested that it's more than likely is valve float , that maybe my springs are weak or the push rod length is off.

The engine I currently have is out of my twin turbo 99 c5 that made 722rwhp @ 13#. Only thing I have changed is the cam. And the cam was spec'd for my current set-up by Martin Smallwood.

I find it hard to believe the valves have gone week from the time the motor has sat in my garage until installing it in the c6. But I guess it is possible because the engine has also never seen 19# of boost.

But anyways, any other ideas of what could be the issue other than valve float?

BLOWNBLUEZ06@RKT Performance

Stock rockers?
Martin is a guy that chooses his cam lobes responsibly, with valvetrain stability in mind. It's not the cam profile.

Kris will figure it out. He's a smart cracker.

ajrothm

Didn't you just put a new cam in it? (239/255).. If so, surely you installed the correct matching springs to the required installed height.

Definitely sounds like valve float.

As for the filter, didn't I ask you on one of the several threads you had going about the air filter and air inlet pipe? I mentioned to you that F1Rs do not like anything in front of them..

I think a spring check and you'll be good to go. 239/255 is a lot of cam, combined with 20+ psi, its gonna need some spring pressure. I would say at a minimum, 160#s closed/450lbs open.. Hopefully you're using stock rocker arms and good/thick push rods.

Kris will get your ride pimped for sure.

Dtownbrown

Okay so we changed cam springs, it picked up like 50hp. So now we are making 728hp/725tq. This is at 5800rpms with 18# of boost. It again stops making power at around 6000rpms.

We are kinda dumb founded at what the issue could be. I called martin Smallwood and gave him the run down. His theory is that the blower is over spinning at lower rpms which isn't allowing the engine to "swallow" the forced air. He got pretty technical and I honestly couldn't keep up with his idea. I'm a dummy when it comes to all the details of forced induction etc... but he suggested gearing down the blowing and allowing the motor to spin faster which should allow the blower not to over spin so soon. Not sure how that works but since I already have a 4.13 pulley we will try that and see what happens.

Fingers crossed

ajrothm

I'd do a compression and leak down test on it before I went any further..

Something is definitely not right..

I have a 4.25" pulley on an F1r which is just past max impeller speed at 7k and my 402 with a baby cam eats the boost up fine down low... Not sure I'm following that theory. You're atleast 100hp off for 19 psi...

Sub'd for the resolution.

Dtownbrown

I done a compression test, all check out to 150/160- #7 was a little lower at 130.

Haven't done a leak down test yet but will get too it.

Dtownbrown

Here's the dyno graph.

ajrothm

HMMM... Something is still not right..

Kris will figure it out... Something in the combo is just off...

Mine is a relatively under achiever, I always thought it should have made more power then what it did...I chalked it up as having too small of a cam and the fact that the F1R is so hard to turn--eats up a lot of power.

So I would expect your combo to make atleast what mine makes as they are pretty close on the combo except you have WAY more cam... I was looking at a cam similar to your.... I think I'll hold up on that now...LOL..

Seriously though, I hope you figure it out...

BLOWNBLUEZ06@RKT Performance

Since you have boost and lots of it and a healthy cam, the only 3 remaining items I can think of are: the cam isn't degree'd right, the exhaust isn't allowing it to breathe or you have a cylinder dropping out under pressure. Kris doesn't think it's the third, so I would look at the other 2, starting with the easier one first.

95vettski

Your hp should be close to 825rwhp...something is not right. Are you sure the belt is not slipping? It's not getting any airflow up high...it's leaking somewhere.

Dtownbrown

I'm a little unsure of the cam degree, slid a cam out, slid a new cam in and make sure the timing marks are lined up. What else can you do other than that?

But that is one of the few things I did put my hands on so I'm not saying I didn't do something incorrect when installing the cam.

99vettski - we have already ruled out belt slip and boost leak, done a boost leak test and it check out. And no signs of belt slippage.

BLOWNBLUEZ06

I degree all cams in. What I've discovered is that the cams are usually right. What's wrong when it's not properly degreed with the marks aligned is the timing sets.
restrictive mufflers. Easy test. drop the midpipe down at the back and make a pull.
Last thing I can think of today: ring flutter or rings not set up right. Fat chance I'm sure, but easily checked. If your cylinders are losing pressure at high RPM, your crankcase pressure will jump drastically at WOT.

02402ramair

I talked with Martin and he assured me a bigger pulley will fix the issue. I have had blowers run out of air up top (6500) and start falling off but never at 5600. I don't see the bigger pulley giving us 200rw.

Looking at the log and the KPA trend it is NOT coming close to running out of air at 5800 or even 6500. Its still climbing at a good rate.

UPS dropped the pulley off yesterday afternoon so I will install it tonight and make a pull and post up the 900 plus rw graph. I hope.



The car was dynoed at another shop with a 5" upper. I would like to see that graph to see if it fell off at same rpm.

Dtownbrown

I will send you a photo of the other graph this evening.