okay heres the situation,

crane 22's with dialing out the over lap with cam gears,

or 16's or 18's

looking for the best combo:
Getting a custom grind is not outa the question but having some good numbers to send to brian crower would be nice,

if custom i think going with the lift of 22's and the duration and overlap setup for a turbo car would be good but could i acheive the same numbers with a dialed in 22 ??


this is going to be ona turbo 2.4 with boost ranges from 15(pump gas)-28psi on avgas
usging a large t40e turbo
8.5:1 compression,
ported Head,
Greddy E Manage with e01 boost controller,
all the sensor hookups etc...

valve springs will be upgraded with rockers and retainers
probably new valves too,

Go big, make it a beast.


22's IMO
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Car Sold


http://hometown.aol.com/ohshootuhh/
www.Fast420A.com

Its gonna be a beast but the question is which would make more power?
(anything above 20psi ona 2.4 is jsut plain SICK:7 )
1)22's with the over lap dialed out

2) 18's tuned properly?

3)Custom grind with the lift of the 22's and the duration and over lap setup for a turbo car

of course gonna cost more $$$ for #3 then 1 or 2


these are the factors im playing with, as long as the car idles its good for me on the street i can always turn down the boost =)))))))))))

Bill

20psi? I'd stick with the #14s.


95 Eclipse RS : 5 speed
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

metal jim explain,
why 14's?

all the big neon guys run a minimum of 18's

Bill

Talk to Brian see what he says, he's a good gu, I've dealt with him a lot.



15.9 @ 86.7mph

Injen CAI, 55mm TB, P&P Intake, Crower Cams, Hooker Header, ERT/Catco Cat, GS-T Muffler, AFX UDP, Crane Ign Amp, S-AFC

Well, mostly because you haven't said anything about whats really important about running big boost on big cams - CR, turbo specs, and to some extent other head work. 14s have a nice low overlap which should prevent alot of reversion regardless of displacement.

Reversion is bad because it causes detonation. With a street turbo, exhaust pressure is usually higher than the intake pressure. When all your ports are open(at overlap) the exhaust gas will force it's way back into the cylinder. As the overlap and pressure differential(between exhaust and intake) increases, more and more exhaust gas will be present in the combustion charge, raising heat and lowering efficiency. If it's bad enough(big overlap - high pressure differential) then it will also start finding it's way into the intake manifold, which raises heat even more. Basically, reversion causes heat and heat causes detonation.

Is anyone running the 18s at 20psi on the Lotus head or a ported Neon head? What CR are they running? What turbo are they using? Is the turbine ported/clipped to increase exhaust flow?

The main reason I suggested the 14s is that 14s are safer than 18s. Reversion is something you can "tune" out - like the a/f ratio. Changing cams is alot more difficult than turning a screw on the fpr, but it is most definately a tuning aspect - even moreso than a/f because it changes your VE.

I'd hate to build up a engine with a target set for 20psi and be limited to 12 because of detonation...but I might run 16s if I had a 25g or ported/clipped 20g feeding a low CR 2.4L through our head.


95 Eclipse RS : 5 speed
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

the turbo is a t40e 60trim,
.60 a/r exhuast housing

for the time being and break in and trouble shooting of the turbo system it will have a internal 39mm flapper until i get a tial 35 or 40mm i havent decided what will be needed yet,

the compresion ratio is 8.5:1 it has some chumbuston chamber work so it very well might be .1 or so lower per cylinder,

fully ported head, with bowl work, ive yet to decide on OS valves or not,


now would 14's have enough lift to suffice my beast?

if u had a choice of a custom cam build what kind of lift would u choose ??



most of the neon guys are running a medium to large t4 most non clipped, on 8.5:1/8.8:1

>the turbo is a t40e 60trim,
>.60 a/r exhuast housing
>
Wow, that's a BIGun!

>for the time being and break in and trouble shooting of the
>turbo system it will have a internal 39mm flapper until i get
>a tial 35 or 40mm i havent decided what will be needed yet,
>
>the compresion ratio is 8.5:1 it has some chumbuston chamber
>work so it very well might be .1 or so lower per cylinder,
>
>fully ported head, with bowl work, ive yet to decide on OS
>valves or not,
>
Sounds good.

>now would 14's have enough lift to suffice my beast?
>
Absolutely. It doesn't nessicarily mean that the cams need to be bigger just because the displacement is bigger. In this case especially, where the only thing that's really changed is the stroke. Duration is measured in crank angle. Think of it this way, 180 degrees is the full stroke - on a 2.0 it's worth .5L of swept volume per cyl whereas on the 2.4 the SAME EXACT duration sweeps .6L per cyl.

I suppose another proof for the 14s being enough is that Crane thinks so. Compare their PT 2.4L specs with the Mitsu 2.0L specs. They are EXACTLY the same.
http://www.cranecams.com/import/mitsubishi.htm
http://www.cranecams.com/import/pt.htm

>if u had a choice of a custom cam build what kind of lift
>would u choose ??
>
Any upgrade is better than stock. My gude regrinds have a .376 lift with 237 duration. I don't know if I would choose them or not but that's what I have. I have to get some boost on them to see how they do. The 14s look like a nice upgrade(for a turbocharged engine). Off the top of my head, for a custom setup I'd stick with Crane but I'd rather use a 16 intake and a 14 exhaust cam - 374/345 lift, 250/238 duration. I think that would be nice - even for your setup. Then again, you should probably vew my choice with a grain of salt, cause I would rather be on the safe side...as opposed to the race side.

>most of the neon guys are running a medium to large t4 most
>non clipped, on 8.5:1/8.8:1
>
Sounds like your setup. Are they able to hit 20psi with 18s, 20s, 22s? I mean if they've already done it then there you go.



95 Eclipse RS : 5 speed
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

well a few have done it ive yet to speak specifically with them about their expirences ive had a few people rcomend straight 18's and dial out the overlap,

armond told be go huge on the lift a while back and as long as it idles its streetable...

i just want to hear opinions and thoughts on the idea, metal jim u do a good job on the cam shaft info, just like to see couple different sides ive got a thread at neons.org going too seeing what they say, darrel cox (phat ridz) is a odd one he likes crane 24's on their turbo neons,(2.4)

On our 2.0L, once you build up the bottom end, you can run enough boost with the stock cams to make mroe power than most people would ever drive in a street car.

I'd imagine with the 2.4Ls extra displacement combined with some boost, you'd be in even better shape. I'd stick with the #14s if you are going to turbo that thing. It is certainly easier tuning with boost and fuel than replacing cams :)

14's would be easy to tune but if im going to all this trouble to make this motor run in the 500-700hp range why not squeeze the msot out of it, i still have a couple weeks before cam decision needs to be determined,

ina turbo application does lift make too much ofa difference vers how long they are open?

You sound like you are already convinced on the 18's. People are telling you 14's and you are defending the 18's, Just go with those or the 22's ;-)
________________________________________________________________________________________
Car Sold

http://hometown.aol.com/ohshootuhh/
www.Fast420A.com

I have the crane #14 grind cams in my car, i will soon be turbo, am i going to run into problems with this cam...its not a huge cam but deffinatly bigger than the #12s....currently i have them tuned so i have no overlap...will that be good enough?

im not convinvced on anything yet i do like a little bit of constructive argument though it helps the info and learning process,

at this point im still unsure as what to run,

Bill