New to 2.7 > have questions

[farleyd]

Hi guys, i just bought a rebuild 2.7 and have some questions. If you could help, id appreciate. Ok lets go. I have these options. Can someone gives the pro/cons/faisability of each?

A) stock CIS cams/pistons with Webers and headers. Good for 180Hp or so.

B) stock CIS cams with high comp pistons (9.5:1 JEs) along CIS injection. What should that give?

C) stock CIS pistons with CIS cams reground to 964-specs with Webers? What should that give?

D) high comp 9.5:1 JEs CIS pistons with CIS cams reground to 964-specs with stock CIS induction? What should that give?

Thanks!

[Randy Webb]

If you're gonna do all that, why are you keeping the CIS cams or pistons? Kill both and go with JE pistons and an S cam. No CIS.

[bigchillcar]

I'm investigating the same thing, basically, for my 2.7L. I'm keeping my CIS (good driveability), but am considering the 20/21 grind cam from Web-Cam and 9.5:1 pistons/rings. With my 7:31 r/p tranny, I'm betting it will be a monster! 150 hp right now, maybe 200 later? It would be awesome! This engine would pull all the way to redline and have a fatter torque curve.
Ryan

[farleyd]

Why keeping the CIS? Already have an engine 2.2E with S-cams that has a power curve similar to what a 2.7RS clone would have. Too peaky for the kinda drive i am doing. I prefer the broad power curve of the 2.7CIS or Webers. Keeping the engine over 5K RPM to make it alive doent appeal to me. Plus, that goes onto a 914/6 conversion. Such a light car will have enough with the 180HP+ i am aiming at, event qith some CIS component. Later!

[Halm]

I tend to agree with Randy. If you are going to tear the motor down anyway, use the high comp pistons, an E cam and webbers. According to BA, that combo is one of his favorite motors. . . And it's what I am doing!

[farleyd]

As i said, i had everything to do such a beast, RS p/cs, E-cams and Webers. Plus i know a guy who owns one. He clearly mentionned that the engine is tough to ride below 4.5K. After that mark, goes straight to 11 on a scale of 10.... Not what i wanted. I am driving my car, not racing. And want a much broader power curve.

[si2t3m]

''Such a light car will have enough with the 180HP+'' You'll never have enough... MOUHAHAHAHA!!!!

I'd slap it in there as it is now (CIS pistons/cams) with the webers from the 2.2 (re-jetted) and beat the ***** out of it.



Marc-André

[TerryBPP]

I wish I had webers. CIS sucks if you get a leak!

[farleyd]

''Such a light car will have enough with the 180HP+'' You'll never have enough... MOUHAHAHAHA!!!!

Mmmmm... guess ill have to desinflate his tires at the next xcross.....

Youll see MA, youll see. If my 914 cant beat you, ill buy a Camaro....

[Halm]

Originally posted by farleyd
... Plus i know a guy who owns one. He clearly mentionned that the engine is tough to ride below 4.5K. After that mark, goes straight to 11 on a scale of 10....

Wow! It would seem to me that a motor with 8.5 compression and E cams would need something extra to rev to 11K. Additionally I have read either here or in BA's book that as displacement goes up, the "peakyness" of cams diminishes thus making even S cams easier to drive at low RPM.

I went and re-read BA's chapter and he described it as "a wonderful, fun to drive engine."

I am looking for the samething you are so I really hope your friend didn't give you the whole story on his motor.

[farleyd]

Halm, ive read Anderson too, many times believe me. But my friend (JP Stein in fact) mentionned that while not as pesky as 2.2S or 2.4S, 2.7RS set-up is better in high RPM. It was a question of money too. I just regained the 1.3K the RS p/cs cost me. Dont forget my starting point, a 2.2E w/Webers and S-cams. Fun to drive, but i have to push it over 4K to have it behave. Just want a broader curve and more torque. Thats why i ditched the 3.0L option in favor of a 2.7. Believe me, a 3.0L is a nice engine in a 914, right Marc-André??? The rebuild with all upgrades 2.7 i found is a good compromise.

- - -

Back to the topic. Am i getting in a land of confusion going CIS???? I mean, i can sell the Webers for 1K, your CIS is 500US$. Gain 500US$ for less power. To have equivalent power, add 350US$ for 964 cams. Thats leaves 150US$ gain for a comparable engine. I am not 150US$ short, so does it really worth it???? Whats the advantage?

- - -

IYO, will just slapping Webers and headers onto an otherwise 2.7 CIS block will make a better engine than:

> a stock CIS - p/c’s - cams? (cost less money)
> a stock CIS - p/c’s with 964 cams? (equal cost to keep Webers)
> a stock CIS w/964 cams and JEs 9.5:1 pistons? (more money than keeping the Webers)

Thanks for taking me out of darkness and chronical indecision....

[Halm]

Hoping the HP Junkies will jump in here. . . I don’t see how a stock 2.7 with CIS making 150 HP can be modified to generate 200+ HP without some combination of decreasing MPG, poorer drivability and an upward moving torque band. If the biggest difference was simply throttle response, why don’t we see more motors like Noah’s and fewer RS clones?

Also, is a 2.7 with RS p&c’s, an E cam and Webbers even capable of routinely hitting 11,000 rpm as a redline without significant head and bottom end work?

Inquiring minds want to know!

[farleyd]

[bold] hitting 11,000 rpm as a redline without significant head and bottom end work?

[/bold]
I wasnt referring to RPM, but to the sound of a Marschall electric guitar amp.... that only has a10-scale sound level, but seems that guitarists always finds a way to make it sound louder...

About Noah’s engine - keeping everything CIS with high. comp. pistons and 964-cams, i believe that theres a somehow -macho- effect sporting carbs over CIS, even if its known that carbs are producing more power, but HOW MUCH MORE isnt that clear. Most gain will be using less restrictive exhaust system.

My CIS system starts at 165HP. Add 10-15 for the headers plus some more for the Webers and youre close to 190HP, not 200HP for sure.

[Halm]

LOL I completely agree with your numbers. I am just not a believer in a "free lunch". That was why I asked why don't we see more CIS hotrods. Or is it as simple as a "period correct" issue?