WOW! Big performance gain!!!

[Twin_Turbo]

The stock stamped rockers are actually only about 1,48:1 .

If you use 1,6 rockers the valve lift increases and if you have a high lift cam you might have problems with either valve to piston clearance of the valve springs binding (which will result in wibed lopes, broken springs, bent pushrods.. .not good )

If you have the stock L82 cam you can run the 1,6 rockers, no problem. Just watch the geometry and the motion of the (roller) tip over the valve stem and make sure that in all it's travel the roller never goes on or over the side. It's all in correct pushrod size. Normally this won't give any problems.

 

[Glensgages]

WOW! Big performance gain!!!

Zector, my 17,000 original mile '82 is perfect, flawless, and running as-delivered from Bowling Green, Ky. (i.e. not up to Corvette-standards!). I am considering modifications like you've done, and am told that "TurboCity", in California, has a 'Cross-Fire Injection' up-grade kit available (re-machining the TBI's, modifying the computer, etc.) This may/may not allow more agressive camshaft, timing, etc., in the Cross-Fire system. I'm told the main culprit is the intake manifold, limiting RPM to under 4500. This being the case, I'm considering building a 383"-406" motor w/ aluminum heads, an RV-type (truck/motor-home) cam, etc., tomaximize low-end torque. If I proceed, I'm hoping for an 'honest' 300 HP or more, and with a small nitrous kit (50-75 HP), I hope to get my '82 into the 13-second range in the 1/4 mile, maybe run with the C4s & C5s, while STILL running the Cross-Fire. If anybody in Cross-Fire (Cease-Fire, Miss-Fire; I've heard them ALL!) Land has any advice, I'm sure Zector and others would appreciate the input! P.S. I think the cam in L83's (Cross-Fire motor) was spec'd at .390" intake/.410" exhaust lift, like my '79 Z28. If I'm correct, going to 1.6 ratio rockers will yield lift #s of .416"I/.437"E. Long ago, a .450"/.450" lift cam was placed in my other-wise stock Z28 motor, and NO piston-valve problem arose. If memory serves, I think up to .500" lift, depending on duration, was OK w/ OEM having 'notched' pistons from GM. Good luck w/ the '82!!!!!

 

[Twin_Turbo]

The turbo city manifold IS bone stock, it's a plain crossfire. The throttle bodies are slightly under 2"and expensive too. On the crossfire forum there's a guy (lionsden) who bores TB's for a fraction of the cost and you can go much bigger with sleeved units.

The turbo city ECM is just a simple 1227747 Truck TBI ECM. You can get them dirt cheap. The proms you have to burn yourself but the turbo city prom isn't a tuned item either, it's just a one size fits all type deal. A couple of guys are working on the 7747 ECM with some add on boards so it will plug directly in the original harness (you have to cut the harness with the turbo city stuff.. crimped stuff makes for great electronic problems) Also, they're developing flash rom so you can tune on the fly like the later models w/ power programmer.
300 Hp is easy, you won't need a 383 for that. A 220@.50/112LCA cam, a pair of worked on L98 heads, headers and good exhaust will get you there, along with some minor work on the intake. No need for TB's larger than 2".

The L83 has forged 464664 L82 TRW manufactured pistons with a single 3"cc valve relief.

Don't waste your money on what the mags say, they only print that stuff because turbo city pays them to print it. There's enough guys out there that have done this stuff before you. Learn from their experiences.

The crossfire injection vault: http://www.crossfire.homeip.net

Marck

 

[cruzer99]

Glensgages,
I have had several friends use the "RV CAM" in there small blocks and everyone of them were very unhappy with the performance. They all have replaced them with a real cam.
Chevy's get there HP/performance with RPM's. They like the high rev's so to me it's not smart to put in a cam that dies at 4500-5000 RPM when that is when a SBC is waking up. My understanding of the RV CAM is high torque at low revs.
Just my .02.......

 

[Glensgages]

I agree on Chevys like RPMs, but if the intake 'chokes' the airflow, does it matter HOW big a cam, cylinder head, injector, etc., we put with it? if the intake acts as a 'restrictor-plate' on a CFI, I'd think we have to build 'WITH-IN' the parameter. I may be wrong; in fact, I've BEEN wrong before, but... SHOULD we match a 6500 RPM camshaft with a restrictive intake? Any help is invaluable. Glen

 

[cruzer99]

O'BOY.......this is going to open up a can of worms.
I don't disagree with what you say but why put a limited cam on top of the limited intake.
I think the sernaro goes:
1. Put in the cam............not happy
2. Redo the intake.........still not happy
3. Redo the heads.........now the cam is killing you
4. Put in the cam that should have been there in the first place.
5. Happy
I have seen this happen several times.

 

[Twin_Turbo]

;stupid

do it all at once and do it right or don't do it at all.

 

[Glensgages]

Cruzer82, I 'agree' w/ you entirely on a 'combination' of parts working in unison. BUT, if intent on using the original, un-modified or mildly-modified CFI intake, all the cam and/or cylinder head in the WORLD won't help air-flow, correct? I'm 'new' to this 'EFI/CFI' type stuff, but I've raced enough the last 2 decades to know that one 'inferior' piece of a puzzle will ruin ANY chance at the best 'possible' combination. I am interseted in running as strong as the '82 can go, WHILE 'appearing' to use the 'basic' CFI set-up as much as possible, if for NO other reason than to maintain what value this 17,000 miler-has. To run 'close' to the LT1/LS1/LS6 crowd, with the lowly CFI, would open many eyes, I'd think. In closing, I agree, if not intent on using as much 'OEM' pieces, by all means, go with a .500" lift, 240 degree @ .050" lift cam, good heads, etc. If, in my 'CFI education', I realize the modified-CFI intake will flow upwards of 5500-6000 RPM, I'll plop for a more aggressive profile. I value any, and all input on this subject. Glen.....

 

[cruzer99]

In reading what Zektor did (roller cam), sounds like a no-brainer path to get a big HP gain without doing your heads, intake etc. I think I will be going in that direction with my stock 82.
My impression is that Zekor did not open up his engine except to do the cam and just doing that got a great performance gain.
I think this is a great discussion to have, it might change my mind.

 

[Glensgages]

cruzer82, not trying to chage minds; I'm trying to educate my OWN. As I said, I'm new at this EFI/CFI stuff. My 3800 pound '79 Z28 runs easy 12.70's @ 106 MPH on SUNOCO 94 w/ a carb, but this EFI-stuff..... this conversation will enlighten SOMEBODY I hope, including me! Although I've owned it 3 years now, I just got involved with my '82 Corvette's performance recently; I didn't KNOW there is/was alternative intakes (the 'X-RAM'?) for CFI's. In many ways, I'm starting school all over again. Where's the 'lil boys room?

 

[Redbob]

Sounds good. $175. Spring time. Its to friggin cold now.

Sorry to be the one to break this, but I think he said "pounds sterling" (or that funny 'L' abbreviation therefor) not "$".

At current exhange rates, that's $284!

 

[Redbob]

The stock fan never freewheels but it has a visco clutch. If the temps get higher the viscous fluid gets thicker and the fan will have less slippage.

Marck

That's not exactly how a viscous drive fan clutch works.
In fact, there's almost no change in fluid viscosity over the entire operating range of the clutch.
In the "low-torque" (cool) mode, there's only enough fluid in the drive section of the clutch to reach a certain maximum torque, so fan speed will increase with engine speed until it reaches a maximum, then it will more or less hold that speed constant as engine speed increases further. This maximum fan speed might be no more than 1200 - 1800 (fan!) RPM or so, depending on the clutch.

There's a coiled bi-metal strip in the front of the clutch, at the center, which senses air temperature coming through the radiator. When that temperature exceeds a preset value, the bimetal thermostat uncovers a port inside the clutch, allowing more fluid into the drive section, developing more torque and driving the fan to a higher speed. So now the fan will track engine speed up to a much higher engine RPM, up to perhaps 3500 engine RPM or so, at which point fan speed will once again level off, remain constant, as engine RPM increases further.

When air temp behind the radiator drops back down, the thermostat closes the fluid port, the drive action of the clutch pumps the fluid back into the reservoir section, and fan clutch torque drops once again to its' low-torque mode.

Regards,
- R

 

[Zektor]

Redbob,
Actually, It's probably still about $175 in the states. Because I live in "Rip off Britain", they tend to convert the dollars into pounds. Where it really should of cost me about £125. They say this is to cover the cost of shipping etc. But I think it's a load of crap... it's just a way of making more money out of the punters.

Cheers
Dazza

 

[Redbob]

Just think of it as a tax, like on tea...

 

[skeetimer]

I didn't KNOW there is/was alternative intakes (the 'X-RAM'?) for CFI's.

What is X-RAM? Where can I find out more info on it?

 

[page62]

I made a guess and I was right:

www.x-ram.com

BTW: In reading the last few posts, I think there's been some confusion. Correct me if I'm wrong, but all Zektor did was install a set of self-guiding, steel roller tip rockers. About $190 bucks (not Pounds Sterling) from Jegs or Summit.

 

[Twin_Turbo]

The X-ram is a weiand x-celerator manifold milled down and with a plenum on top that accepts the stock TB's AND fits under the hood. It gives a performance gain over a bone stock manifold but dyno runs have shown that there's only a 25Hp gain when only swapping the X-ram. You can also get that with some work on the stock manifold.

The first thing to say would be, what if I add heads, cam, exhaust. Well, sure you will gain more but there's also a couple of stock crossfires (manifolds modified) that have that and some are putting out way over 325Hp.

The X-ram is NOT a crossram manifold like the stock. It's a 360deg manifold.

Theré are other options besides the X-ram (which is non emissions legal like these others) The only thing is you need to fabricate a top plate for them (not that hard)

The Offenhauser crossram, may give wiper motor problems on 84 Corvette, has been solved with different motor.

The Edelbrock STR-10, discontinued, similar to offy, no wiper problems. Will appear on ebay every now & then

Edelbrock SY-1, Smokey Ram. Discontinued, but best solution, possibly highest performance potential because of the somewhat shorter runners and design with center plenum devider. These are the most expensive manifolds (used) of the 3.

For pics and info go to http://www.crossfire.homeip.net

Marck

 

[skeetimer]

What can I do to my stock CF manifold to give me more performance? Can I do this myself? Where can I get it done? About how much does it cost to modify the stock manifold?

 

[Twin_Turbo]

go to the above mentioned site and look in the tech articles. There you will find an article on modding the manifold and the swirl plates in the lid. You can do it yourself, you'll need a die grinder to do the work.

 

[80RedL82]

I am intrested in installing the roller rockers on my 80 L82. Will these rockers fit under the stock L82 Valve covers? They are the aluminum finned ones, which if I remember correctly are not a "boxy" as the L48 stamped ones. Thanks in advance for any input. BTW I am new to the forum..... great info! Semer Fi Bob