jeremym

iTrader: (3)

This is going on a TFS 235cc head 414ci motor. My old cam was a 244/248..612/615..112 or 114LSA. The new cam specs are 254/254..595/595..113+2 LSA. What do yall think? How much power should I gain up top and will I lose down low? My goal is 20+rwhp up top. My old cam peaked 5900-6000rpm and the new cam should peak out at 6300rpm. I have a SLP 85mm MAF in it now and was thinking about putting the stock MAF back in it. Should I or not? Which is better?

Stang's Bane

iTrader: (22)

Damn dude, can't you ever leave well enough alone???LOL

jeremym

iTrader: (3)

I will tell yall who speced the cam later because of all the internet haters and the internet nut swingers. Just want a honest opinion everybody.

WizeAss

iTrader: (5)

adjustable timing set... you will change the power curve by degreeing it properly... go ahead and get a 2 piece cover while you are at it too.... that way you can get it on spot.

Cam sounds good..... lift is a little low... wonder why? I dont see why not go to .620's or so lift... cant hurt... wont change anything other than taking better advantage of the peak head flow numbers.

Bigger is better on the cam for your setup. I am running a crappy cam in my setup for now..... til I spec a custom one down the road for the LS3 heads. I assume either Tooley or Chris spec'd it......

as long as you degree it right... the fact that it has ground advance should help make it more peaky.

Dragkid1917

iTrader: (2)

id go with a bigger lift my cam in my ls1 (though less duration) has a bigger lift than that... .62 or .63 would definitly make u the power wit that duration

racecar

IMO, needs more exhaust duration, like 248/254.

WizeAss

iTrader: (5)

why? single pattern cams work great. Those heads flow very stout on the exhaust..... think about things... you flow more air in... less air out. The air leaving the cylinder is no longer oxygen, heptane, nitrogen..... it is after the combustion .... it take up less space. why do you think folks go with reverse split cams.... like 254/242?? I think that a wider exhaust duration is only necessary when your intake to exhaust ratio is way off kilter, like when your exhaust flows significantly less than the intake.... as in the LS3 heads or LS7 heads.

racecar

It's amazing how many different cam combinations there are. The only way to know for sure is to dyno each one with the same engine and a good tune. The split that I see most people using with good results is 6 degrees more on exhaust. If you are making good power going the other direction, go for it.
Back to his original question about which MAf to use; take it off and go SD tune.

slow trap

iTrader: (22)

he has a great exhaust system and some believe it is overscavenging. 545rw is great numbers, especially peaking around 6000-6100.i'm interested to see the results and a graph to see the tq difference down low compared to the hp gain up top.good luck.

jeremym

iTrader: (3)

I will dyno it before the cam swap and after the cam swap the same day or the nxt day.

JL ws-6

iTrader: (50)

I understand the thoughts on the lift, the intake only flows xxx amount of air so pushing the valve past that point too much for too long will only cause more valvetrain wear, and possibly hamper the flow.

The cam sounds good to me, try it. I'm going ot be intrested to see the before and after results. Are you changing the heads first and testing them with the original 244/248 and then changing the cam and retesting, or are you testing the heads and the cam at the same time?

Please swap the heads, test with the 244/248 then put the new cam in and test that... the results will be MUCH more meaningful from that test.

WOTFMAN

iTrader: (3)

A reverse grind with that long intake runner would really suit it better IMO.. no advance straight up. Probably cut it on a 112 and install it on a 114. With the strong mid flow on those heads an XFI Com lobe would suit it well but you could still run a XE-R and really throw some duration at it to get it rocking.

jeremym

iTrader: (3)

I am not changing heads. Just the cam. The TFS are already in the car.

WizeAss

iTrader: (5)

seat timing.... intake close is 58 ABDC.... the cam has 2 degrees advance and 28 degrees of overlap. your old cam had 20 degrees of overlap and a sooner Intake Valve Closing point. You seemed to of lost some dynamic compression with a later intake valve closing point. A 58 degree should help you make more power up top and move the powerband higher up in the rpms.... if what I have read is accurate. Seems to be a more peaky cam with less power under the curve. Now if only I could find out what cam changes and seat timing points are good for a short runner intake with less cross sectional area overall? :help:


Bore - 4.060 inches
Stroke - 4.00 inches
Rod c-c length - 57 inches
With a static compression ratio of 11.8:1.
Your camshaft specifications call for an inlet valve closing of 58 degrees ABDC (after bottom dead center).
Your chamber volume is 78.57 cc's. With this camshaft your dynamic, or effective stroke is 3.09 inches.
Your dynamic compression ratio is 8.94 :1 corrected for cam timing, altitude, and rod length.
Your dynamic cranking pressure, corrected for cam timing, rod length and altitude is 183.47 PSI.
Your dynamic boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 0.00 PSI is 8.94 :1.



the cam I have (that was very similiar to your old cam) is:

244/248 .612/.615" 113LSA +2
Cam Valve Events 0.050
Intake Duration - ID 244
Exhaust Duration - ED 248
Lobe Center Angle - LSA 113
Intake Centerline - ICL 111

Intake Valve opens - IVO 11
Intake Valve closes - IVC 53
Exhaust Valve Opens - EVO 59
Exhaust Valve Closes - EVC 9
Exhaust Centerline - ECL 115
Overlap................ 20
Timing Advance..............+2

Your new cam:
254/254 .595/.595" 113LSA +2
Cam Valve Events 0.050
Intake Duration - ID 254
Exhaust Duration - ED 254
Lobe Center Angle - LSA 113
Intake Centerline - ICL 111
Overlap................ 28
Timing Advance................+2


Intake Valve opens - IVO 16
Intake Valve closes - IVC 58
Exhaust Valve Opens - EVO 62
Exhaust Valve Closes - EVC 12
Overlap................ 28
Timing Advance................+2


Why is the intake valve closing point so late? That seems like it will chalk up the idle and create a bit of reversion.

WizeAss

iTrader: (5)

For my L92 408 setup.... something around these numbers??:

Your engine summary is as follows:
Bore - 4.030 inches
Stroke - 4.00 inches
Rod c-c length - 57 inches
With a static compression ratio of 11.25:1.
Your camshaft specifications call for an inlet valve closing of 53 degrees ABDC (after bottom dead center).
Your chamber volume is 81.57 cc's. With this camshaft your dynamic, or effective stroke is 3.23 inches.
Your dynamic compression ratio is 8.88 :1 corrected for cam timing, altitude, and rod length.
Your dynamic cranking pressure, corrected for cam timing, rod length and altitude is 181.89 PSI.
Your dynamic boost compression ratio, reflecting static c.r., cam timing, altitude, and boost of 0.00 PSI is 8.88 :1.

WizeAss

iTrader: (5)

I am attempting to learn more about cams...

What are the following effects of the swap?

Reversion: more or less :::: I assume More?
Peak HP: higher or lower from 5252rpm :::: I assume Higher?
Vaccuum: more or less (would he need a canister?) :::: I assume less due to more overlap?
Idle Quality: Better or Worse ::::: I assume not really effected or worse due to overlap
Nitrous friendly: Less or more ::::: I assume Less due to increase overlap at TDC and less exhaust duration over intake duration?


I am still reading on how changing cams seat timing changes all the above. Any expert insight is appreciated.

WizeAss

iTrader: (5)

I believe that cam is on XER Lobes..... he has it cut on a 113 with a plus 2 advance..... a reverse grind.... like a 254/244 that would be better with a long runner? I would assume that would work if the exhaust was up to par. Considering the exhaust does not need the same amount of duration to move air as intake (thanks to compression of the spent gasses) it makes sense to me to do a 254/254? Where as in my case with heads that flow like a bitch on the intake and not so great on exhaust the split would be needed to help the exhaust... also the intake valve close would need to be at 49 or 50 degrees (especially considering the carb short runner intake) hmmmmm figuring out a cam for a single plane and L92's will be a bigger challenge than I originally thought. From what I can tell.... single plane's do well with really low LSA's.....



So for me... how about 244/258 111 +3

that would have a IVC around 50 and exhaust at around 15? Centerline is what.... a 108? Wouldnt this work with a single plane? 29 degrees of overlap..... that should work well with a single plane right? How do you cam this bitch right w/o having to guinea pig 100 cams?!!!!