328 Supercharger...I think it's time

Oooh, this looks like a thread to follow - good luck Mike!

All the best,
Andrew.

 

I've been debating this also (ITB's or SC). I contacted them 1 or 2 months ago and they confirmed that they still sell the kit for the 308/328.

It's my understanding you can, within limits, choose your power level increase based on pulley size. What are you plans? I was thinking 75hp would be a good "compromise" between value for money, reliability and the abilities of the standard suspension and brakes.

 

I asked the shop doing my engine conversion about going with the SC, since I was no longer stock, to say the least. I specifically asked about the 928 kit. The response I got was to consider the Forza kit as it was more complete / bolt on / more thought out. Just what one shop told me.

 

How long did you own your 328 before you thought it needed more power?

-DrC

 

My stock 328 seems fine. But after I drive other vehicles I have that are more powerful I start thinking the 328 needs more power. Drive a Prius before you get into your 328. Then it seems quite fast.

 

Sounds great Mike! Best of luck with the project.

And you will not be able to keep your foot out of it, that I can assure you.

 

Good update Mike.

On another note... I thought I had read at one time on FChat that if you supercharge a 328 (turbo or compressor) you should switch to copper head gaskets. They felt this was needed on the 328 (and I assume the QV) but not on the 308. I think someone from Norwood was being quoted. Maybe it was because of some smaller/weaker areas on the head gaskets for a 4V head vs. a 2V head??

Anyone know of this/remember this??

 

I know James at Norwood told me 328 head gaskets don't like ANY detonation. On my QV I had a couple injectors fail casuing the cylinder to go a bit lean and.....blow out the flame ring in the cylinder. The funny think is I didn;t realize exactly what had happened and jdrove it another 5 years before tearing it down for something else and discovering the problem.

 

Mike, will any changes have to be made in the fuel delivery system or does the Bosch system have enough extra capacity to deliver sufficient fuel for the 6 psi boost?

 

75hp added to what? To your current hp or to what the engine had when it left Maranello?

Last year I got an accelerometer and measured the hp on my QV for the first time and was shocked. I had lost more than 75hp and my engine is in good mechanical shape.

At some point I'd like to get a SC as well. But quite frankly I'd be already happy to get the car back to where it was in hp. Not that I mind some extra...

So adding 75hp probably won't bring it into 355 territory unless the 355 lost an equal amount.

 

Curious as the to the feasibility of going the turbo route versus SC route? I have seen turbo kits on ebay several times....not that I would ever consider it on my current car, but to me the turbo route on the surface of things seems like a more 'appropriate' upgrade with the tie in to the GTO and F40 lineage and could even potentially be an easier install. Is there a reason why it seems most folks here opt for the SC?

Now going way overboard here but has anybody ever built a TC 308 using the same setup as Ferrari did with the GTO and F40, with the IHI twin turbos and Weber Marelli injection? Not sure if any of this stuff is still available.

 

I haven't done either one, but the SC looks to be about 80% less work to install, as you won't need new headers, or have the hassle of fitting them, the turbos and the air plumbing from turbos to plenum.

Doug

 

Instant low-end "grunt" improvement vs. a turbo too. Smoother power delivery. Perhaps less overall heat increase in the engine bay??

 

Someone once told me that: superchargers are really good for low-to-mid rpm grunt, but become terribly inefficient at higher rpms, while turbos don't do much low down but keep improving the higher you rev.

^ We'll have to wait for someone with a mechanical mind to come explain either why that's the way it is or why that's nonsense. ​

Assuming for a minute that's true... Ferrari engines are quite high-revving, so presumably that favours a turbo installation?

All the best,
Andrew.

 

Yes, very true. A supercharger, being belt driven, builds up pressure immediately, therefore boost. Turbos work off of evacuated exhaust gas, so it takes some time to build up enough pressure to get the boost through the intake manifold. Since superchargers are belt driven they are going to sap a percentage of the overall power, just as an AC compressor does. Since the turbos work strictly off of exhaust pressure they don't rob any power, and once in full steam will make more peak power compared to a equivalent supercharger.

I don't see a supercharger installation being all that easy of a job either. You are going to have to add a pulley somewhere off the crank, then plumb the sucker into the intake manifold which seems like it would be just as difficult as plumbing the exhaust for a turbo. Also unsure as to how you guys get these thing to fit under the decklid. It seem like it would be a tight squeeze. Now, as Rob pointed out and what it could all come down to as to which scenario would be easier, is the FI. I believe you have to run a different FI setup with the turbos.....is the case with the SC as well?

 

Or perhaps an SC for better low end torque?

Depends on your app, city streets or Daytona, I guess.

Doug

 

In the 80s the supercharger option was a roots type blower and they had some problems.....and turbo's were all the rage so they were being forced on to apps they didn't really fit.

Today, things have changed a bit. Both turbos and superchargers have come a long way but the fundimental strengths are that same. Superchargers are better at going from low power to high power and product a flatter, smoother torque curve making them a better choice for most street applications. Turbos have a higher system efficiency making them a better choice for anyhting that spends a good portion of it's time under a heavy load particularly is low/high power changes are smooth like road race and trucks. All that said either can be made to work pretty well in street or track apps but supercharge for the street, turbo for the track is to take the best advantage of the strengths

 

Lancia utilized the best of both worlds (compressor and turbo) in the mid-80's to build one of the most bad-azzzz cars of all time (the Lancia Delta S4).

http://www.youtube.com/watch?v=XPkjxENPdAY

http://www.youtube.com/watch?v=LTIKUYMlhoo&feature=related

http://en.wikipedia.org/wiki/Lancia_Delta_S4