Lance J

Calling All CIS OB's tuners goal for 2009 is 375rwhp
1979 CIS 4.5. USA model
1) Supercharger or Turbo -with a Variable Meth/water Injection system
2)Supercharger or Turbo-LPG conversion
3)Supercharger or Turbo-propane injection w/turbo or supercharger
4)Supercharger or Turbo-euro goodies swap
6)NOS

What seems to be the best way to add 375RWHP to a CIS 4.5 liter Shark
Cost, Simplicity, Reliability

Goal: To get the quote out of my head "Sell the OB and Buy a S4"

RicerSchnitzzle

$1000 and you have a great N2O set up and can easily reach your goal. On my Euro S before the 5.0L bottom I was over 450RWHP with a progressive 200HP shot. Now running a 250 shot and hoping for over 600RWHP when she's back together.

That being said, N2O has lots of limitations. If you're just looking for dyno bragging rights, go for it. If you just want to toast the Ricer next to you, light to light, go for it. If you want to go fast throguh the twisties under giggle gas..forget it. When the budget allows, I will go boost, most likely turbo.

Nitrous is all or nothing. That being said, it's cheap to install, simple to install and actually safer on your engine than boost, if done correctly. Long term cost of N2O will rise each year as you refill bottles. Boost is pretty much a one time investment. Then again, $6K buys a lot of bottle refills.

Final benefit of giggle gas is you can take your set up to your next car.

karl ruiter

I am building a 4.5l motor for my convertable. I have:
-4.5 l bottom end
-Euro S heads, cams, intake, CIS, and throttle body
-Vortech blower
-FAST bracket
-Supermodel pulley
-928 Motorsports intercooler
-Porken's 16v'r (with updated square tooth pullies and belt)
-Porken's porkensionser

The project is going slowly right now, and it looks like I won't have time to pull the block the rest of the way apart until next month. Then I'll have the scratches on one hole machined out and the assembly will start in ernest. I'm not sure it there is a local dyno here or not. But I think 375rwhp may not be out of the question

Thought about swapping a S4 motor in there, but this is so much more my style.

PorKen

The force is strong with this one.

ddarnell

Lance,
I'm building a boosted M28/11 for my wife's 78 5sd USA. An Eaton M112 on a custom CF intake with an air/water intercooler. Shooting for around 9psi. Will NOT be using the CIS, however. I just can't see tuning max power with CIS. Will probably go with an MS-II and EDIS. I'm gonna want to control timing and of course A/F. 375rwhp should be easy with this combo. If you want to keep your CIS I'd start with as much power as you can get ie: the Euro S motors. If you start at 300hp (at the crank) it would be easy to get to 375rwhp. I would think that a centrifugal supercharger with intercooling, blowing through the CIS with a relatively low boost would get you there. Fuel enrichment may be accomplished with one of Carl's WURs or perhaps a rising rate pressure regulator. Mine won't be done in 2009 so I won't meet the goal.

"Who needs an S4?" (quote for 2009)

IcemanG17

The ??? you need to ask yourself is how much $$$ you are willing to pay for a certain level of HP?? The bottom line is a S3-4 928 can make 300+whp ease....which is not so easy with a 16V 928...even a euro 4.7L...by the time you add boost...it cost more than a S3-4.... My track shark has 100% stock internals and is over 300whp with only easy to replicate exhaust mods?

RicerSchnitzzle

A 4.7L Euro with cam and headers will make more than an S4 for thousands less $$$. Even going 5.0L bottom with flycutting and you're still less than an S4 with more power before you even think of boost. Cost difference almost pays for a SC kit.

There are CIS cars going over 200mph... Folks need to get over the "CIS Limitation" You may not be able to fine tune every last HP or MPG but it holds it's own with a much simpler system. Check out the unwired tools electronic WUR. You can plot A/F over vacuum vs rpm. Basically you now have a programable CIS. It works well with boost too. Increase system pressure and you increase flow to the cylinders, it's that simple. Control pressure is regulated seperate and with the unwired tools you can keep it in balance with the new system pressure.

Carl's getting over 450RWHP with his lightly modified CIS. Plenty more room.

It may be easier to get HP from an S4, but for the cost difference the Euro S can still get there with change to spare. That buys a lot of Taco Bell.

IcemanG17

Ricer
I'm not saying that CIS is bad...after all Porsche used it on the turbo 911's for years after the 928 dumped it.....

When it comes to "value" for HP gained.....sure the 16 V's are "cheap"....but when you mention 16V's over 200mph......are you serious? I can name two 32V's normally aspirated at over 200MPH....Tim & Cheryl Day + Marc & Susan Thomas....well documented in ORR....George Sunnen will be in that club this year too....but with 32V.................

Honestly I don't know of 1 16V boosted-nitrous-whatever that has broken 200mph.........

RicerSchnitzzle

Sorry, not clear enough. Didn't mean a 928 16v over 200mph..yet. Just a CIS vehicle over 200mph.

IcemanG17

Okay this makes sense since I believe (doubtful since I've been drinking ALOT) that the yellow bird had CIS and went 211 mph?

toofast928

375 RWHP on a 4.5 with OEM internals is too much to wish for.
300-350 flywheel HP is all the pistons are going to withstand. Believe me I know these things.

Now if you want to be in the 400HP range with the OEM look of the spider, (saving money keeping the fuel system). The 5.0L Hybrid is the way to go.
Or look at the S4 conversion thread Kevin did.

Tony

dprantl

You are kidding yourself if you think there is a better value 928 than a US '85. You can find one for $5k in good condition these days. It has the 5.0 bottom end and for a couple hundred bucks you can add the S4 intake and get S4 numbers. Or just supercharge it and you are at 400rwhp. Total investment ~$12k. It's also the easiest and fastest way to get to 400rwhp.

Dan
'91 928GT S/C 475hp/460lb.ft

shmark

I'm with you, and I happen to prefer the 16v engines for their sound, durability and simplicity. I also like the sound of a single exhaust too. Carl is totally right, higher hp is very possible with the early engines. There are 2.5l 951s running well in excess of 400hp and I know of a couple 1.8l NA 914s making north of 160hp. So a 4.5 or 4.7l V8 should easily cross that mark with the right development. Personally, as soon as my fun fund recovers a little cash, I'm installing a full euro top end (intake, throttle body, cams, heads), along with my existing Y-pipe and a nice catless-back. That should be good for 250+ on a low-compression 4.7l bottom end and will sound incredible. And it's a great basis for higher boost application.

Dennis Wilson

Porsche got 375 HP out of the 2.0 liter 924 turbo with the following mods.
1. moved the fuel dist and sensor plate to the filter side of the turbo.
2. installed forged low compression pistons (no change to bottom end or cam).
3. went with one bar wastegate
4. installed a 928 fuel distributor and had two injectors per cylinder
5. installed a large hood mount IC

A 4.5 928 CIS with .7 bar (10 psi), water alcohol injection and programable WUR should achieve about 374 HP. An intercooler would let you increase the boost and achieve even more HP.

Dennis

CAShark

programable WUR? Does this really make a difference? If so, how? Just curious.