3.5 N/a vs. 3.6

[Randy Webb]

Bill, my engine has 993 intake valves (larger, and about 24 g. lighter than stock, about the same as the CS intake valves) according to the machinist. I didn't build the heads, but have no reason to disbelieve him. I had suggested the CS valves but he showed me a trick tool he has to allow use of the 993 ones. A tool for a Bridgeport that is.

[Carrera3.5L]

Well I guess I should have read the opening post with a keener eye. If he doesn't have an engine at all and needs to either buy a core 3.2L to then make a 3.4L or 3.5L or buy a 3.6L then I think the answer is simple: buy the 3.6L.

I think the costs will end up about the same once you figure in the 3.2L core purchase. But, tearing down the 3.6L to the case and updating the problem areas would be the smartest idea.

Good luck with whatever you decide!

Ralph

[drummer323]

Well from the posts, the 3.6 seems to have a strong majority. What is the best year to look at for this motor? What trouble areas should be updated? Who makes the best and most complete kit for the install? Finally, what year of 915 should be looked at for the best all around results for this type conversion. I of course want to install an l/s/d/ unit in the 915. Thanks for the replies.

[Mike Feinstein]

Not sure of the complexities, but the G-50/3.6 combo is a match made in heaven.

[Lukesportsman]

The G50 just raised the cost bar up a rung. Check with Patrick Motorsports on their options. Read Steve Timmins sight about his opinion on this. It depends on if your trying to save weight and money or want that ultra smooth shift above all else.

If you ever think about boosting the 3.6, then you better get the G50 before going any further. Doesn't Better Bodies do this also?

Planning on coil overs or are you trying to keep torsion bars?

[Bill Verburg]

If you ever think about boosting the 3.6, then you better get the G50 before going any further

I strongly disagee my 3.8RS eats tire like nothing bu the 915 has held up fine. There are quite a few other w/ similar experiences.

[Bill Verburg]

my engine has 993 intake valves

Randy that's interesting, he probably installed the narrower 993 guides. That's a good move that I hadn't heard of before, because of the lightness of the 993 valves relative to 964 or Carrera valves.

[drummer323]

I'm using larger torsions 22/29 or 30 and 22mm frt and rear sway's. What year of motor and 915 should I look for?

[Randy Webb]

Bill, At the risk of prolonged side conversation here (no objections yet).... yes, I think I recall that he said he did go with the 993 guides. Not sure what is involved in getting them into the heads. He's pretty old/experienced and a very cagey race engine builder... I don't know if the 993 valves are lighter than the Club Sport intakes or not.
Also has Ti keepers - the valvetrain is supposedly good to 8,000 rpm - tho I have some mild street cams in it and the hp peak is at 6,200 on the dyno. Cheers.

[Bill Verburg]

I searched all over for a '84-86 Carrera 915/67 or 915/69 or 915/72 trans w/ lsd. Thes etransmissions are the last and strongest of the 915s and include factory oil coolers.

As for the engine there are several routes that can be taken '95 has the advantage of OBD1, '96-98 jhave the advantage of vram, all ROW hav eth advantage of OBD1, US '97, '98 are easier to "chip" than '96, to "chip" a '96 the DME needs to be replaced w/ a "97 or '98.

If extanesive cam and intake changes are anticipated then '95 is a better place to start. If a relatively stock config up to 3.8 RS is wantyed then vram is the place start.

My engine choice was a ROW '97 OBD1, vram M64/21(manual transmission harness)

[Bill Verburg]

The 993 valves are lighter than Carrera CS and potentially larger(though much more expensive ) in the 51.5 mm RS flavor, there are even larger sizes available(both in Carrera/964 variety and 993 variety) but for street use they are too big.