Performance Improvements

rdrr · 03-19-2006, 03:31 PM

I'm going to be doing a top-end rebuild on my Carrera 3.2 in the near(ish) future and would like to find out what performance upgrades can be carried out at the same time. My car is primarily a street car with regular use on the track (once a month). I would like to end up with some performance improvements, but the engine should still be easy to drive everyday and hopefully last as long as a stock engine before the next rebuild. I'm not looking to build a race engine.
What upgrades are recommended? What sort of HP increase can be expected? And of course what will it cost?

kenikh · 03-19-2006, 05:09 PM

If you have the heads off, you have a lot of options. Using Search would be easiest as this topic has been covered over and over. What is your budget? That will tell all.

If it were me, I'd go w/ 10.5:1 CR pistons, twin plugs and Mod-S cams (I think these will still work on a common plenum). Of course that will cost you US$3000 in parts. That said, the car will scare you witless with the increase in power. This combo has over 270 HP of potential.

Jeff Alton · 03-19-2006, 07:42 PM

The factory intake and motronic will not like that Mod-S cam at all. The common plenum intakes need a cam with much less overlap. There are some good choices out there that will fit your needs. So, if you want the big cam, factor in carbs or ITB's and an ECU. $$$$.

I am building a 3.4 right now from my 3.2.

It specs out like this.
3.4
10.5 CR
Twin plugs
DC44 cams
1 5/8 headers w/heat
ARP hardware everywhere
46 PMO carbs

I am hoping for 27o + at the wheels.

Cheers

911-32 · 911-32's Garage

You are basically limited to 964 or 993 Supercup cams if you stick with the common plenum intake manifold. The Supercup cams push the powerband up about 400rpm and the power above 6000rpm doesn't tail off so quickly. My euro car with SSIs and Supercup cams was making 260hp before being remapped, so 260hp is a very attainable goal, possibly as high as 270hp (flywheel hp). The downside is that the idle is rough and very cammy and the emissions are not so good - if you have those restrictions in your area. Accordingly, many people chose 964 cams that give a little lift in performance and still pass emissions.

Costs? If you are doing a top-end, then its the cost of the cams plus whatever you choose to improve for high rpm reliability, so valve springs, retainers and rod-bolts. Add SSIs or even better B&B headers plus a muffler. If you extrude hone the intake you can get a little more hp again. In the UK, one tuner particularly likes the late 964 plastic intake as a replacement for the 3.2 intake. The resonance flap can be made to work correctly with a separate rpm driven controller and the tuner swears the intake is good for 10hp at least - but I have not seen a definitive dyno plot to confirm. It needs adaptors to fit the 3.2 heads.

After that you are looking at new Ps & Cs for a 3.4/3.5 and/or more radical cams. You can do a lot more but you asked in the context of a top-end rebuild

kenikh · 03-20-2006, 06:14 AM

Quote:

Originally posted by catca
So, if you want the big cam, factor in carbs or ITB's and an ECU. $$$$.

Cheers

Individual throttle bodies will certainly wake up a 3.2 for another $1000. Well worth it.

Why can't ITBs be used with the Motronic ECU? They have accomodations for the requisite sensors. They have attachments for TPS and MAP. Is there somthing missing?

JeremyD · JeremyD's Garage

Depends on the fuel too - if you have access to good quality fuel you can get away with 9.8 to one 3.4 single plug - 993 Super Sport Cams - extrude hone - decent headers

I'm pretty happy with my 244.3 at the wheels, hopefully a little more on the dyno with my software revision. Dynojet 248c

Jeff Alton · 03-20-2006, 05:11 PM

Quote:

Originally posted by kenikh
Individual throttle bodies will certainly wake up a 3.2 for another $1000. Well worth it.

Why can't ITBs be used with the Motronic ECU? They have accomodations for the requisite sensors. They have attachments for TPS and MAP. Is there somthing missing?

Not sure where the 1000 dollar ITB's can be found!

You could probably use the Motronic but tunning and programming it would be difficult. That is where the new ECU comes in. Infinite tunning potential......

Cheers

JeremyD · JeremyD's Garage

Damn Jeff - 270 = you go boy!

ChrisBennet · ChrisBennet's Garage

Quote:

Originally posted by kenikh
Individual throttle bodies will certainly wake up a 3.2 for another $1000. Well worth it.

Why can't ITBs be used with the Motronic ECU? They have accomodations for the requisite sensors. They have attachments for TPS and MAP. Is there something missing?

The 3.2L don't use a TPS ( it looks like one but it isn't) or MAP sensor and I don't see any pins on the DME for it. (Though it could be there in the guise of something else.)

I think Protomotive offers a MAP conversion to support their turbo conversions. Do you know any more about this?

As much as I like playing with these motors, I don't think that it is cost effective to do much to the internals of a 3.2 to make more horsepower. Fun? Yes. Cost effective? Not IMO.

A cat test pipe and a chip is a pretty good bang for the buck but more than that and you're getting into 3.6 conversion money. What I mean is that you should consider buying a 3.6 and selling your old motor.

-Chris

kenikh · 03-20-2006, 07:22 PM

Quote:

Originally posted by catca
Not sure where the 1000 dollar ITB's can be found! You could probably use the Motronic but tunning and programming it would be difficult. That is where the new ECU comes in. Infinite tunning potential......

Cheers

I thought TWM ITBs were about a grand...

Jeff Alton · 03-20-2006, 08:25 PM

Ahhhhhhhhh yes, if you already have the manifolds and linkage etc from your webers. Basically if you buy the whole lot from TWM you are looking at only a couple hundred less than the Jenvey's, which IMHO are quite a superior product. I have held the Jenvey's in my hand but never actually set up a motor with them. However, I think the number will start with a "2". I am a chicken when it comes to tunning a car with a computer, hence my choice to go with the PMO's even though I can get the Jenvey stuff at cost!

Cheers

Porschekid962 · Porschekid962's Garage

Jeff if tuning an efi motor scares you, you need to checkout the Autronics website. Their upper end ECU's have an autotune feature, you plug in a goal AF/R and the brain programs the motor accordingly, assuming you have done fuel and ignition which I am along with the Jenvey's.

You have your 3.2 intake, dme, all that, sounds like a turbo setup is in order! For na, I have seen a nice little 3.4 litre in a 914 running the stock intake with 993supercup cams, chip, higher cr and it ran great. No idea on the power hike though. Best of luck