3.2 to ???

[Rtrorkt]

have a perfectly good bone stock 3.2 in my 69 tub. No reason to do anything to it except to do something to it. Have talked with some who have converted to a 3.5. What are the suggestions and if you provide a suggestion a budget. Most likely i will have a professional shop do the work.

[Buechsen Gustl]

I think it would be cheaper and more reliable to put a 964 or 993 engine in it, if available...

[ur2ez2tz]

I'll be going from 3.2 to 3.5l at some point. Most likely with the LN Engineering cylinders and other usual upgraded components.

[darrin]

Originally Posted by Buechsen Gustl

I think it would be cheaper and more reliable to put a 964 or 993 engine in it, if available...

Not sure I'd agree with the "cheaper and more reliable" part any more - with 3.6l engines getting older and more $$$, I'd be concerned with the reliability of a non-rebuilt 3.6. Once you open up the 3.6 to address valve guides, etc., you've effectively "eaten" the $$ advantage of going with a 3.6. OTOH, sticking with a known quality 3.2 and addressing issues (valve guides and bearings and ??) during the rebuild to a 3.5 would leave you with a known good, rebuilt engine . . .

At least this is what I'm thinking while weighing what to do with my 3.2 . . .

[jeffbottman]

The other obvious idea is low boost turbo, anyone have comments on this approach; whether parts and expertise exist anymore to do this. Assuming owner is not an expert mechanic and the work is done by a good shop.

[patz]

open wallet or buy a bigger engine.

[Ferrino]

Keep the 3.2 and make it sing with an ITB setup, like the Jenveys below!

[gtc]

Just sell the car as it sits and buy something faster and already sorted.

[Trackrash]

An exhaust upgrade with a matched chip will bring a reported 250HP from an otherwise stock 3,2.

After that the sky is the limit, depending on your budget.

Do a search in the engine rebuilding forum as there are a couple of threads dealing with upgraded 3,2s.

[Slanski62]

I've researched this question lately and gotten opinions from a lot of learned people. My conclusion is that the bang for the buck stops at a dual plugged 3.4 and picks up again with a 3.6 swap. A 3.5 isn't cost effective compared to either a 3.4 or 3.6.

[jeffbottman]

Again my question ... couldn't a low boost turbo increase power to north of 300 HP while costing much less that the NA alternative??

[darrin]

Originally Posted by Slanski62

I've researched this question lately and gotten opinions from a lot of learned people. My conclusion is that the bang for the buck stops at a dual plugged 3.4 and picks up again with a 3.6 swap. A 3.5 isn't cost effective compared to either a 3.4 or 3.6.

Interesting observation -- what causes the 3.5 to no longer be cost effective?

In my case, my 3.2 now has 180k on it, with a top end overhaul @ 80k -- it's running just fine, but I'm getting the itch for more. While I understand that the 3.5 conversion requires machine work (and attendant case splitting) that's not needed for a 3.4 conversion, seems that given the miles on my 3.2, splitting the case to inspect bearing, bottom end, etc. should be done either way. I don't think the extra machine work needed to fit the 3.5l cylinders would be that much of an added $$$? (but what do I know?)

[Slanski62]

A 3.4 conversion would allow you to bore and re-plate your existing cylinders. This saves about $1500. If your heads were fly cut before, you might need to open up your domes to accommodate the bigger pistons. So the $1500 plus the cost of more machining and you're getting to the point where a 3.6 starts to make sense.

[darrin]

thanks, that makes a lot of sense --

[jeffbottman]

3.4 vs 3.5 is less than 3% expected power increase; so what's the point??

[Rodsrsr]

Originally Posted by jeffbottman

Again my question ... couldn't a low boost turbo increase power to north of 300 HP while costing much less that the NA alternative??

YES... I've gone over this scenario many times and simply couldn't justify the cost for either upgrading the 3.2 or moving to the 3.6. The HP gain just isnt worth the dollars spent. After doing a top end rebuild on my 3.2 with a pair of 20/21 web cams I decided to go turbo. For half the cost of a 3.6 I now have a mostly fresh 3.2 with modern Precision turbo, web cams, headers, intercooler, Hooligan muffler, and MAF I'm close to the 400 hp range, still fully streetable. Just take the dollars spent on the total build and divide by the horsepower and you'll quickly see how much you are paying per horsepower on a na engine.

[jeffbottman]

That's an impressive engine, Rodsrsr. Did you buy a kit or pull the parts together yourself? Sure wish I had your great expertise. How do you deal with the knocking problem with stock high compression pistons/cylinders?

Originally Posted by Rodsrsr

YES... I've gone over this scenario many times and simply couldn't justify the cost for either upgrading the 3.2 or moving to the 3.6. The HP gain just isnt worth the dollars spent. After doing a top end rebuild on my 3.2 with a pair of 20/21 web cams I decided to go turbo. For half the cost of a 3.6 I now have a mostly fresh 3.2 with modern Precision turbo, web cams, headers, intercooler, Hooligan muffler, and MAF I'm close to the 400 hp range, still fully streetable. Just take the dollars spent on the total build and divide by the horsepower and you'll quickly see how much you are paying per horsepower on a na engine.

[Tippy]

Originally Posted by jeffbottman

Again my question ... couldn't a low boost turbo increase power to north of 300 HP while costing much less that the NA alternative??

350-375 intercooled at 0.5 bar.

On a 3.2, you can use a BEGI rising rate FPR to handle fuel and MSD BTM to retard timing under boost.

Add turbo, wastegate, IC, and headers of your choice.

[darrin]

Originally Posted by jeffbottman

3.4 vs 3.5 is less than 3% expected power increase; so what's the point??

not sure it's that straightforward -- understand the actual size of a 3.4 to be a bit under 3.4l and a 3.5 to be a bit over 3.5l -- if already planning to replace (rather than rebore) cylinders anyway, why not get all the displacement increase that's available?

As to turboing, see this as a personal preference issue -- love the immediacy of power delivery in a N/A engine and not a fan of the turbo lag I've felt on factory turbo engines. Would be concerned that a self-engineered turbo solution would have more lag than I'd want (along with the potential detonation issues you pointed out if n/a compression was retained).

[Rodsrsr]

Thanks jeffbottman..... what Tippy says in regards to fuel and ign retard. I sourced the parts which is relatively straightforward. Lag is non existent on a turbo 32. The reason for the lag on the old 930's was an antiquated turbo and extremely low compression. I run a Precision ball bearing turbo with the normal compression of the 3.2, there is zero lag. Additionally I wouldn't say these are self engineered, as now many companies offer components that are basically bolt on to form a complete system. I didn't have to engineer anything. These are parts that are tried and known to preform for this application, which is why Tippy knew the exact answer to the fuel and ign retard question. Its the solution that has been used for years on these low boost systems. Nothing new.