Which engine to build?
 

What motor would you build out of a 3.2 if you had the choice, and why would you chose it? I am debating between a 3.2 with euro 10.3 pistons or a 3.4 with 9.5 or 9.8 pistons. I want to stay single plug if I can. Both motors would probably run 964 cams and use SSI's and custom SteveW chips. What would the power difference be between them?

Thanks, Jeff

The biggest displacement that your budget and the OE fuel management will allow.

Jeff: I'm looking at the same decision. I believe I'm going 3.4 with close to 10:1 compression, and keep stock (chipped) DME.

I've been juggling between this and a 964 transplant, but like the idea of building a motor, and having it all new.

Nothing beats the power of a turbo. :D

Jeff, you know my answer! If you're willing to spend the money for high-compression 95's, spend a little more and get the 98's or 100's. You will be happier with the outcome. The advantage of 98's over 100's is that you can always stick the stock 95's back in if you ever want/need to. With 100's, you are committed.

You MAY be able to get away with single plug with 98's, but I wouldn't try it with 100's. While you have the heads off, have the machine work done (drill 2nd hole in heads and lower valve covers), you can always add the 964/993 distributor, Andial signal splitter and other ancillary stuff at a later date.

You may want to wait another week or two to decide as my 3.5L twin-plug Motronic motor will probably go on the dynojet late next week. We will also be running my buddie's 3.4L twin-plug Motronic motor at the same time. Both motors are virtually identical other then displacement and cam choice (964 for the 3.4L and 20/21 for mine). The compression ratio (9.5:1), induction (extrude honed plenums, overbored throttle body, etc), exhaust (1 5/8 headers with street muffler) and customized Steve Wong chip are identical in spec.

If his motor makes close, as much or more (perish the thought!) horsepower/torque, then obviously save the money and do 98's. If mine makes significantly more (cross your fingers) power/torque, then you may want to consider going with the 100's.

Will let you know the results when we do the deal.

Ralph

Ralph, I was wondering when you were going to respond!! I am not adverse to the 3.5 at all, infact there has been some really good deals on 100mm 10.5 piston and cylinders on ebay lately. What would you estimate the cost to twin plug, not including machining to be?? Splitter, wires and distributor. Did you look at a crank fired option at all??

I am very interested in the dyno runs. I think I will use the 3.8 sport cam from camgrinder instead of the 964 which I have in my 3.2. John thinks it would be a good match. It will be interesting to see just what the power difference is between the 3.4 and 3.5.

Thanks, Jeff

Hi Jeff,

It all depends on what you can get a good 964/993 distributor for. I picked mine up on ebay for $210 (sans caps & rotors) and proceeded to install a new drive belt, dust caps, caps, rotors and vent kit. Getting lucky and buying a good used unit should not cost you any more then $400 if you are patient. I think buying a complete rebuilt unit from Bosch with a 1 year warranty will cost in the $650-$700 range and buying new will be well over $1,000. All prices in USD of course!:)

Here is the short version:

Used Distributor $210
Caps, Rotors, Belt, Vent Kit, Dual Coils, Plugs $240
Andial Signal Splitter $525

You would need to fabricate a new coil bracket as well as decide on what wires you would want to run. Wire sets can be done a variety of ways. Figure anywhere from $250-$550 depending on what you choose.

RSR lower plug hold-down clips and nice wire separators add a little cost (about $100) but will help with the visual and "coolness" of the motor. Not absolutely needed though.

$290 for the machine work to drill the heads and lower valve covers.

Never considered crank-fire for the main reason that it would not pass the visual smog test here in California. The other main reason is that it doesn't look stock, which my motor does except for all of the bright red Magnecor wires running around.:)

Ralph

In the works for me. 3.4: 98mm P/C's -9:8-1 with wedge dome, Super-Cup grind, turbo oil pump with turbo piston squirters, extrude intake, larger t-body, B&B 3.6 street headers, not sure about muff yet, probably contact Steve W. about chip

I have 93 octane where I live.

AsphaltG: Are you planning the motor still or building?

Your list is very similar to what I've put together and got pricing together on last week.

Are you guys staying with single plug in your 3.4's. Also what piston and cylinders are you going to use?

Jeff

Jeff:

I'm going to go with JE pistons, and have my cylinders bored/replated. The guy I'm working with has assured me of no issues with the 98MM pistons, keeping under 10:1 and staying with single plug. We do have 93 octane here in TX.

efhughes3: Buying pieces / parts now. Custom JE's and single plug ignition. After many helpful answers here and through other experienced builders advice this combo is my choice.


I recently bought this car and the chain tensioner failed on a long trip with not-so-good results. I've already blown my budget somewhat with the purchase of the car. My mis-fortune.

Plus I cannot leave anything stock so as long as I was in there I would do it up, but simply. Just maximize the basic config with proiven parts combination.

Asphalt-I understand totally. "Breathed on" is the term I like. I've got a head stud issue (I think), and while I'm at it, a little improvement is in order.

You know, even though I was pissed-off about the tensioner deal, my mind went straight into the world of "As-long-as-I'm-inthere-what-ifs" I'm a hot rod guy 24-7. I just cannot seem to leave ANYTHING alone! From what I see this combo has a lot of potential.

Carrera3.5L has assembled a very nice combination and I am waiting with baited breath on the final HP/TQ numbers. His build was slightly more conservative camwise but more displacement. I think he is under Cali's extremely restrictive emissions programs' thumb + only 91 octane fuel.

Thanks for listing your setups. I am leaning towards twin plug and higher compression right now. I want all the power I can get and I also want something "trick" to show to clients!

Ralph, can you describe in words the power difference now that you have driven the car a little?!?

Thanks again, Jeff

Even though the camshafts aren't radical enough to suck the 330+ hp the 3.5 is easily capable of, they provide power EVERYWHERE, and lots of it. Low-end grunt is especially noticeable! Sweet engine.

Jeff, night and day difference. Those who read my long-winded rebuild threads know that my complaint with the 3.2L was the lack of low and mid-range torque. Nothing much happened below 3,500-4,000 even with Steve W's chip and some minor exhaust mods. The extra displacement makes a huge difference. Nail the throttle at 2,000 rpm in 2-5 and the motor pulls much, much harder all the way to the mid 6's. EXACTLY what I wanted and expected, it makes the car that much more enjoyable to drive.

But I also don't want to give the illusion that the car is blindingly fast. I wouldn't consider it scary fast, but maybe because it is a heavy Carrera and not something lighter. My car weighs about 2,800 lbs with a full tank of gas. I have no interest in lightening the car any more then I have done with removing the heat exchangers and heater blower assembly. The car is heavy mind you (for an impact bumper model), but the extra power this motor makes will at least help compensate some against some of the lighter, less powerful 911's. A mildly modified (i.e. bolt-on upgrades) SC or Carrera doesn't stand a chance, that I can tell you. My buddy Steve used to leave me in his wake with his 3.4L twin-plug motor. Now it should be a bit more even!

With the mild cam selection, the motor does seem to run out of breath at 6,500 or so, high rpm is not this motor's specialty nor was it the intent. The ARP rod bolts and AASCO valve springs were designed more as reliabilty upgrades then as performance upgrades. Even with a smooth G50, you just never know when you might miss a shift.

Yes, I am limited in what I could do horsepower wise due to MY PERSONAL constraints of being easily smog compliant (headers/heat exchangers swap in about 2 hours) and running on 91 octane. As it turned out, the octane really didn't matter much as I could only get to 9.5:1 CR anyway.

As far I'm concerned, mission accomplished. The motor is light years better then it was before in my opinion and should run strong for well over 100,000 miles.

Rapidly approaching 1,000 miles and did a 320 mile 2-day round trip to San Diego last week. Only used half a tank of gas at 80-85 mph. Motor is bone dry underneath and I swear has not used a drop of oil thus far. The dipstick measurement has barely moved. I guess I did a good job of seating the rings, eh?

Even in smog trim, a larger motor is nice to drive. The three of you guys (and any others lurking) are going to have some fun with your builds.;)

Ralph

P.S. - Once again, sorry for being long-winded.

Yeah, Scott can tell you first hand with an unbiased view. He is the only one so far (other then my wife) who has ridden in the car for any great distance. With him, I never took the motor over 5,000 as it only had a couple of hundred miles on it at the time.

Ralph

Man, I wanted to get the February DE uinder my belt before starting in. I might not wait that long. I'm getting pumped about taking the plunge!!

Ralph: My wife and I are coming out just prior to Christmas, we're staying at a new(?) Marriott in Newport/Corona del Mar. If it's convenient, I'd love to perhaps meet up with you and see your baby. We get in sometine on the 22nd, and fly out Christmas afternoon.

Ed,

No problem. I'll PM you my info. We're about 20-30 minutes away so not a big deal. The in-laws will be in town for Christmas so a perfect reason to get away for a bit.

I gotta find a way to get up and see Jeff as well, as he is only about 10-15 minutes from my parents house. He keeps drinking my beer!

Ralph

asphalt,

Sorry if I may have missed your motor's intended use somewhere, but I think the B&B headers are 1 3/4 in diameter. If true and unless this car will be used more on the track, this is too large for a 3.4 or 3.5. You will lose significant low and mid range with them. Stick with 1 5/8 for street use (under 7,000 rpm). The larger headers will only help you way up top and it looks like you may not have the cams to get you there.

If the motor will see more extended high rpm time (over 7,000) and you have the cams to get you there, the 1 3/4 will probably be better, although you will still lose low and mid-range.

You may want to research this area in more detail and try and get some other opinions to confirm or deny.

Ralph

Ralph come on up anytime!! I am moving at the end of feb. but only about a couple of miles south of where I am now. The wine rack will be fully stocked at the new place.

I just bought a 964 dist. so I guess I am going twin plug!!! Where did you source your plug wires, and did you have to assemble them yourself? I looked throught your thread, and if it says, I missed it.

I really do want over 10.1 compression so I am thinking about using JE's. That I guess will limit me to 98mm and a 3.4. I don't really want to shell out for "nickies" in 100mm. Just have to locate a splitter and then I am ready to go!! My head guy will machine the heads and since they were rebuilt only about 10k miles ago they should be okay. Will put in some of Camgrinders springs though. (Trying to support the people who post here as much as possible) I already have 964 cams but am interested in trying John's Supercup cams......

I have access to a CNC machine shop and was thinking about making adapters for a 3.6 intake manifold. What do you think about that, or would the extrude hone be a better option. I don't want to leave too much power on the table untouched! I sell Steve Wong chips so getting a new one should not be a problem!!

6500rpm would probably be a tall enough powerband for me, but I will build it to be safe to 7300 or so with ARP or raceware rod bolts.

Can't wait to see the dyno runs!!

Cheers, Jeff

Jeff,

Congrats on your purchase. Be sure to do the vent update if yours doesn't already have it. Also, you may wish to change the drive belt if you are unsure about mileage on it, they are pretty darn cheap!

Talk to Pete at Andial about the splitter, you should be able to buy at the wholesale price and save a little bit of money at least.

I used custom length 8.5mm Magnecor wires. I had to approximate the lengths after the longblock was done and outer sheet metal was fitted. They made them up to my specs and I had them in a couple of days. Steve Brown over there is a good guy to deal with. Magnecor's aren't cheap, but the quality is very good.

If you do it yourself, you will need approximately 25' of plug wire to do the top and bottom and obviously the extra boots, connectors, etc. as well. My buddy Steve made up his own wire set, but he wanted to stick with black wires and I wanted something a tad "racier" (or is it "ricier"???). Anyway, I'm not sure how a 964 lower wire set would work on a 3.2 based motor, the wires may be too short or too long depending on how you decide to route them. Andial always builds their own 7mm wire sets as well.

Don't know if making adapters to use a 964 plenum is worth it or not. Maybe if you didn't already have a 3.2L plenum but you do...
Andial was getting 5-7 horsepower on their ENGINE dyno with the extrude honed 3.2L plenums, not a huge increase but every little bit helps. In my case, I didn't want to part with any extra money in this area. I had the 3.2L plenum so that is what I was going to use. I don't think you are going to gain huge power in the plenums no matter what plenum you decide to run.

Steve W. has already done many 3.4L Motronics (I think I'm his first 3.5L) and you know how easy he is to work with so you will be fine in that area. We are going to hook up sometime this weekend to get my motor perfect in preparation for the dyno late next week.

You guys and your 93 octane are killing me!!!:)

Ralph

93 octane? 94 available everywhere up here!!!! My only prob is heading to the track in Seattle I have not found anything above 92 down there.

Thanks again for all the advice and time you spend answering my questions!

Cheers, Jeff

Yeah, but you guys are emptying your wallets for it. I have a couple of family members in White Rock and they go down to Blaine to get gas. They don't need 94 for their crapboxes.:)

Ralph

Ralph, This is just our occasional fun car. I don't do auto cross or road course...yet. My goal is to have a real-world-happy street engine.

I have not purchased the headers yet, but my initial choice was to go with the larger primary tube size based on the increased % of displacement, increased air-flow from the aggressive cam profile and extrude intake. I could be wrong here as I am still learning what these engines like and what they don't like.

Maybe someone would advise here that this may have already been tried. Funny part is B&B makes really nice long-tube headers with smooth bends and collector transition but their mufflers are s--t!!

Asphalt,

It sounds like you pretty much have the same goal as I did: a real world happy street engine. Initially, I thought the same as you, bigger must be better and if the 3.6L guys are doing it, I'm darn close with a 3.5L.

I spoke with a number of people who have experience with what header diameter to run and all 5 unaminously said run 1 5/8" on a 3.4/3.5 UNLESS the car will be running at 7K+ on the track with more suitable cams, compression and and induction (i.e. carbs, mfi, efi).

The people I consulted with were my engine builder buddy Steve (formerly of PMNA), Dwain at Vision Motorsports, Dieter from Andial, Steve Weiner from Rennsport Systems and George Narbel (the gentlemen who built my headers). Plenty of experience to draw on there I think.

All said that I will lose significant low and mid range torque with 1 3/4" diameter and for a 99% street motor what is really most important?

I don't have the cams for 7K plus anyway. It would have been stupid for me to use 1 3/4" headers. I wouldn't see any benefit up top and would have felt the loss where I most want and need it.

One thing to note as well, I don't think these long-stroke cranks (i.e. 74.4 and 76.4) are reliable past 7K stock. If you are running those kinds of rpms consistently, I think you may want to invest in some additional crank prepping for reliability.

Hopefully John's supercup grind will be an improvement over the 964 and 20/21's and if they will pass smog as well then it is an even bigger win-win for him, but I still don't see where you are going to be making power over 7,000 rpm with those cams and the way the rest of your motors will be configured.

Ralph

Ralph; again thanks for your input here. Looks like you've already explored that dirt road. Now making changes (on paper) to reflect my new found exhaust knowledge for these cars.

catca,
I just sold my splitter box to Fred Casarramona ("FredC"). He bought if for a mechanic friend Al Bass who then decided he didn't need it. Try PMing FredC, I bet he still has it. He's in Ontario.
-Chrois

Chris thanks so much, the first thing I did was search your name in the classifieds because I remembered you had one recently. Thanks so much for the info.

Jeff

Also, I used 964 plug wires for the lower plugs because I wanted to use 964 lower valve covers. I haven't gotten the 964 valve covers to work yet but I can tell you this about the 964 plug wires:
- The connectors don't have the little rubber skirts
- The wires have really thick insulation and then another layer on top of that. I think they are designed to take the heat. Very nice in that regard.
- I had to buy a complete set (top and bottom) even though I was only using the bottom. They were probably expensive.
-Chris

Thanks for the info, I noticed on your sight that you had wanted to run the later covers but there has not been an update lately. I saw you misadventure with the JE's. Would you use them again?

Jeff

Yes, I'd probably use JE's for my own motors again. The JE's were in no way at fault in the problems with that motor as far as I'm concerned. Lean is mean, very very mean sometimes. ;)
-Chris

Thanks