Comp 280xfi and boost

[tleed]

Has anybody use a comp 280xfi with a procharger d1

Cam specs
Camshaft, Hydraulic Roller Tappet, Advertised Duration 280/288, Lift .576/.570 duration at .050 230/236

[SwampWS6]

I have seen a couple people do so. But I was advised to go custom grind to get the most outta a boosted car. And usually if you go through a vendor like LE or LJMS , its usually no more expensive to get a cam specd out. I had that cam at one point until i spoke with LE and explained why its better to go custom rather than off the shelf.

NA is a little different, its common to run off the shelf grinds hence why HotCam, CC503 and CC306 are so common. Those are the standards for bolt on and stock headed LT setups.

What is the LSA of the cam?

Just my opinion.

[tleed]

Yeah that's what I thought think I broke a inner valve spring the other day and trying to decide to spend the extra coin while the motor is out. It's some much easier just to pull it than try and mess with it in the car guess I need to get with LE thanks

Lsa is 113 btw

[SwampWS6]

The XFI lobe profile is kinda agressive. But it can work. You would also have to get damn near some of the best springs if you want it to last with a XFI cam. When I sent my TFS heads to LE fully assembled he said that the springs that came with my heads were crap and wouldnt last long with his custom cam. So I broke down and went with a better set.

You are only strong as your weakest link. And with boost, springs are very important. So I would buy better ones for sure. Nothing feels worse than have to fix a problem you always worried about

[tleed]

Yeah that's what I have now tfs with the 1.46 springs that came with them they lasted about 30k then I thought a rocker came loose but when I pulled the valve cover they looked ok but I can't see the inner spring I have been getting ready for my d1 install for a while gathering parts just trying to decide to change the cam now that I will be in the motor this weekend but if I change the cam that will include lifter, springs, push rods, valve seals, probably rockers, injectors, intake and a few other things that will make it about a 2k bill plus tune

[NightTrain66]

Those XFI lobes seem to like 145+ lbs of seat pressure to remain stablke at high RPM and if you add 15 psi of boost, you will need 30-40 lbs more and that will require a GOOD spring and GOOD lifters.

Better off using a less aggressive intake lobe that can be controlled easier.

You would want a lil more split also (more exhaust duration).

If you have enough gear and stall and are running enough boost and spinning anough RPM to need a cam around that size, a 231/243 .581/.597 114 LSA cam would be a better choice.

You could run $230 lifters, Comp 977 dbl springs set up at 170-175 lbs on seat and be stable to 7000 RPM.

FWIW, the springs that come on the 23 degree LT1 haeds are really CRUMMY and I would not even run that XFI cam with those springs and NO BOOST.


Lloyd

[SwampWS6]

Thats who I was hoping I would chime in ^^^^^ He was the whole reason I changed my springs

[tleed]

@NightTrain66
That sounds like a good cam it will be going in a 9.5:1 383 with trick flow 195 23° heads with 1.6 rockers do you think I should use a billet cam and what lifters should I use and how much for everything cam lifters and springs and retainers

[NightTrain66]

if its a uto with 4000-4400 stall and 3.42/3.73 gears with 26" tire (or 3.73/4.11 gears with 28" tires) or 6 speed with 4..33-4.56 gears and want power from 4000-6800 RPM, that cam is a good choice.

This is a pretty "long legged" cam for a street car. I just thru those specs out in regards to the cam specs that you posted and what changes i would do to that cam to have a "similat duration" but be better for boost. I as not really saying "that cam" would be the best for your or anyones set up, just showing the changes I would do and wanted to make sure you was THIS part of my post above . . . . . .
'
If you have enough gear and stall and are running enough boost and spinning anough RPM to need a cam around that size, a 231/243 .581/.597 114 LSA cam would be a better choice.

Less gear and/or less stall and/or wanting more low/mid range power, I would use a 226/239 .565/.587 112 LSA cam. This will allow much less gear/stall and make alot more low/mid range power and the same power in the 550-5800 RPM range as the 231/243 cam. The 231/243 cam will start making a lil more power above that and can be 15 HP better at 6800 RPM on a 12-15 PSI boosted set up.

How much boost are you running?

Auto or 6 speed?

If auto, what stall?

What gears in rear?

What tires on rear?

I like the billet cam better when running boost since the open spring pressure can get pretty high.

Typical parts for a typical build would be

Lunati 72438-16 lifters ($220 shipped thru me)
Lunati 74777-16 springs, 75740-16 retainers, Lunati 77111-16 locks ($200 shipped thru me)
$400 billet cam shipped to you.

set up springs at 1.825-1.830 and this valve trane will be stable to 7000 RPM (with proper rocker adjustment and PR length) with the 226/239 cam I mentioned.

"Better" parts would be Manley Nextek or Isky Tool Room springs (add $225-325) Tool steel or Ti retainers, (add $130-300), Link bar lifters (add $300-450). There is really no "over kill" on valve trane part and it seems that you can always buy something better for more $$$ just like bottom end parts (cranks, rods, pistons) but at 15 psi, 6800 RPM and the 226/239 cam I mentioned, you can use the $200 springs and $220 lifters I mentioned.

Lloyd

[tleed]

@NightTrain66
6speed
373 may switch to 410
26" tire
Acording to trick flow my valves are set at 1.78 so I may need +.050 retainers or locks waiting on a valve mic to confirm