turbo v6 vn sluggish down low

[krawczuk]

hi, i went to get me turbo vn v6 tuned yesterday, but the guy said that the cam shaft is out , or needs degreeing in ? cause its pretty sluggish till it hits about 5000 rpm , then after that it runs really well .

the cam is hydraulic , has 240 duration @ 50 thou , and inlet lobe lift is .073 " at tdc.
lift at lobe on ex and in is .326"
eo 84 degrees
ec 36 degrees
io 38 degrees
ic 82 degrees
vacuum at idle is about 10 inches.....

rollmaster single row chain

has 70 mm throttle body , 86 lb injectors , ported heads and inlet manifold 3 inch exhaust system , microtech.

now the cam was installed at zero , ( normal cam timing ) and wasnt degreed in , could this be the cause of the low vacuum and sluggish down low ?
i presume the differance between std cam timing and dialling it in , is VERY little , would it make that much of a differance ? if that isnt the prob , what else could it be ?
thanks,
mark k

 

[VPioneer]

I know that not dialing in a cam after doing those sort of mods can cause a bit of hastle. But im pretty sure that the reason you've got no power is that your cam is way to big. Im maxing out a buick V6 myself, its N/A, race pistons...porting.... and the cam i have chosen is 216 @50 thou, now thats pretty lumpy for a V6 and the furthest i would go until the idle gets to bad for me (im not even putting my counter balance shaft in). Turbo cams are hell smaller than N/A cams because N/A cams have overlap whereas turbo cams dont, because if they did all your boost goes straight out the other end...

I dont know very much but i meen where did you get your information from to do get this far? Has the motor been built professionally?

Is the low vaccum because of your turbo setup? Maybe your turbo is not big enough or too big? Are those the camshaft manufacturers specs?

 

[hispeedvp]

any aftermarket cam must be dialled in. you need the cam card, and a degree wheel. the cam card will stipulate how many degrees before or after tdc the cam should be set at. the only problem you may have now is with the cam gears. you may need to buy an adjustabe set depending on the cam. take it to someone who knows what there doing, its not good to run a car with a cam thats not dialled in correctly.

 

[14secvp]

Turbo cams will tend to have a larger intake duration and lift compared to the exhaust side.

 

[greenfoam]

I think your only problem is that the cam is too big for a turbo, way too big, it's never going to make power like that

 

[hispeedvp]

could be the lobe seperation is to close, esp in a turbo, woulb be blowing straight out the intake into the exhaust, either way id get it looked at if your sure before you kill something

 

[greenfoam]

It's the overlap that's the problem on that cam, it has way too much, a little bit of research before the engine build would have been good because it's going to need a new cam to be drivable and make boost in a decent rev range

 

[hispeedvp]

whats type of cam is it and whats the part number?

 

[VT-565]

It is a big cam, but just to add on the topic of turbo cams, you have to watch exhaust gas reversion which will send cylinder temps through the roof and cause all sorts of trouble.

 

[cracker]

Turbo cams will tend to have a larger intake duration and lift compared to the exhaust side.

other way around dude, its getting helped with the intake but not the exhuast