New info on FP cam page

[Caithness]

Just noticed they've changed their spring recommendations for their cams, and are now much more specific about what the cams need. Big change for the FP2x-
"FPCam2x
Dual valve springs required. This cam needs 280lb of force over the nose of the cam. When using STDuals, you will find that an installed height of 1.470-1.490" is needed. This "x" version of the FPCam2 increases valve acceleration and valve dwell near max lift to increase torque and widen the power band. Similar to the FPCam3 but not specifically designed around the piston speed of 100mm stroke crankshafts."

Went from "dual springs recommended" to "you need to shim our dual springs that are stiff as hell to start with". Some of the other cams had changes in the requirements too, the 2x was just the biggest jump.
http://linux.forcedperformance.net/...de=FP&Product_Code=FPCamInt&Category_Code=DSM

 

[T9S1i]

Nice find! I bet a lot of people will be glad to know that at least they DEFINATELY need them now.
I wonder if FP has told the people that have already bought these that they are required.

 

[daren_p]

While that is what they recommend for the 2x's, its probably listed just to cover their asses. That way if someone does have an issue they can't come back saying they didn't know etc., etc., which is a smart thing to do. It seems there are more then a couple guys on here that run the 2x's with upgraded single springs and haven't had any issues. Some even rev past the stock 7500 redline...

 

[Caithness]

I've seen some of those posts. To me, it seems like they're too specific to simply be covering their ass. If they had said "Oh, you need our springs" then it might seem like they're just trying to get people to buy their springs, overdoing it on the spring to save themselves any trouble from marginal spring setups. But they list specific spring rates so you could use any capable spring, and specific installed heights for their springs, which makes me think this is a result of their testing or feedback from customers- maybe some sort of spring sackout or people floating valves. FP is a pretty trustworthy company. This is all just my opinion, interpret the data however you want.

 

[bigjdog84]

The reason why they went into such detail was because the supertech springs need to be shimmed in order to sit properly in most heads. There were a few people that were having problems with the seat rocking around, but did not want to shim the hell out of the spring in fear of excessive pressure.
I know in my case, without shims, the spring seat did not fit properly. Therefore they were shimmed as per FP's recommendation. Its a lot of pressure, but is needed to prevent valve float when reving to 9k.

Caithness, good points. If you find a spring that can produce that amount of pressure other than the ST's lemme know
You can only shim a spring so much before it stops increasing pressure.

 

[arash15]

FP2's and FP2x's have different specs. thus why one requires upgraded valvesprings and retainers and the original FP2's can be driven on stock valvetrain with no ill effects.

 

[bigjdog84]

FP2's and FP2x's have different specs. thus why one requires upgraded valvesprings and retainers and the original FP2's can be driven on stock valvetrain with no ill effects.

Very insightful post. Thank you for stating the obvious.

 

[CanadianTSi]

I've taken the 2x's to around 7700 probably 50+ times, hell i need to ride the limiter in 1st gear now at the track, without any problems and I'm running single Manley Springs.

 

[Caithness]

What's the spring rate of those things, seat and at full lift? Is it in the 80/230 range? I've been looking around and it seems that the extreme spring requirement might be tied to a 9000+ rpm rev limit. If the spring rates I guessed from blowing up the product image on slowboy's site are correct (wish they'd list them with all their springs) you're down around 45-50lbs over the nose if they're installed straight up. If FP is targeting their recommendations to people running to 9500 rpm then I could see the Manleys being ok around 7500 rpm. Above that, it's hard to know, and minor valve float can be hard to detect until you push it too far. I guess it's a judgement call you have to make. Personally I'd spend the extra hundred bucks on the duals over the singles to have less to worry about.