Hey Steve for those of us on the right side of the country with 93 octane, what's the range of gain that we'd see with your chips?

Here's info from a recent email from Todd Knighton at Protomotive. They sell turbo kits for 911s and although earlier cars are not supported in the website, he says they still have all the fixturing around to put together '84-'89 turbo kits.

The 'stage 1' is bolt-on and only needs a healthy engine, clutch, and transmission, apparently. Claimed 360 HP with .5 bar and no intercooler. Note prices are from 1999.



http://forums.pelicanparts.com/uploa...1414704080.jpg


http://forums.pelicanparts.com/uploa...1414704097.jpg

I went the 3.4 route w/ 9.5:1 comp ratio and no twin plug, 964 cams wong stage 2 chip (93 oct) M&K muff and pre-muff. Car has not been to the dyno. I can tell you that there is a VERY noticeable power increase especially lower rev range. Very happy with the results. MUCH more fun to drive. And it was done for a fair amount less than your goal of $7500.

I also have yet to dyno mine but it feels strong. Just got it back from top end rebuild including:
AFM conversion, bored throttle body, extruded intake, 20/21 cams, SCARGO headers, and custom flowmaster single exit muffler. Currently has a basic SW chip, but will dyno and get custom chip in the near future. I will post results when I get my lazy butt organized.

Good luck with the build and nice car!

Thanks for all the replies, suggestions, some really good food for thought.
The top end situation is making me think. I’ll keep a log on the oil consumption and see how it goes. My last 87 which was wrecked in Sept was well within spec at 77k miles. I had another 87 about a dozen years ago which I owned from 86k miles to 106k miles and it was running through a bit over a qt ever 1000 miles.
I am not a fan of going turbo. I owned an 1989 RUF Modded turbo about a 12 years ago. I don’t miss it like I miss some of the others I have had. The idea of going to 3.4 P&C doing the cams and the heads is pretty interesting. Not sure that going the twin plug route would make the budget or if it really needs it?

Pros and or cons of the twin plug?
Any thoughts on just going to Carbs or ITB’s over 3.4 P&C’s?

Thanks!

Couple shots of the 89 Turbo and the 87 Targa from 12 years ago

http://forums.pelicanparts.com/uploa...1414709109.jpg

http://forums.pelicanparts.com/uploa...1414709129.jpg

Both carbs and ITBs will sacrifice driveability a little bit, which was the point of my question. But the cool factor and the sound will both go up substantially.

Also, do you have to worry about smog?

No smog worries. Not concerned about the sound unless its ridiculously loud. and I don't drive around with the rear lid open, cool factor is moot. Thanks!

The twin plugging is not a deal breaker at all... no worries as long as you get 93 routinely and stay below 10.5;1. But with that said if you do the cams. you mine as well have the heads done..and if you do that, the twin plug machining is a couple hundred bucks. you can plug the holes and not use them until you slide further into the abyss( do not discount this ..IT WILL HAPPEN). in my twin plug i disable one of the MSD units to run single plug in vintage racing. but i also run 110 race fuel then. the cams and bore delta will make the biggest diff. but also , as indicated aboce alter driveability. Carbs vs ITBs depends also on wether this is a DD and if you use it all year.. carbs in cold weather suck sometimes.. lots of options:D:D

I mean the sound is REALLY cool. And I'm not talking about impressing people. I'm talking about going to check your oil and thinking to yourself,"My car is so cool!"
Yes. I'm totally a dork.

I do understand you don't want a Turbo. FWIW, a turbo'd 3.2 is not like a "Turbo" because you don't have the low compression off boost. It's much more drivable day to day, imho.

I hear yaa.... last weekend I pulled the car and the bike out onto the lawn and I stopped and stared.

Geneman - why did you remove the EFI/ITB combo and replace with carbs?

I'd say the best part of going PMO carbs and/or ITB is that it changes the character of the engine (from what I have read). Turns it into a quick revving, MFI type motor that is fun to drive. The challenge is cost, driveability, and torque. Thinking of doing this myself.

The advantage of Carbs & ITBs is that it allows you to run a hotter cam with more overlap without running in to reversion problems from a single plenum.

Twin plug allows higher compression without detonation, it also allows larger cylinder bore sizes, because the spark plug hole is offset.

It has been a while since I looked at this, but IIRC the determining factor on this is the dome shape on the piston. The Max Moritz style was shaped such that it would work fine on 1 plug, but the higher dome RSR type really needed 2 in a 98mm bore. Maybe Steve@Rennsport will chime in and confirm if my memory still works.

Actually, maybe he doesn't have to, see the section on twin plug here: Gasoline, Timing & Twin-ignition | Rennsport Systems | Porsche Performance Systems and Support

I think a twin plug conversion on a Motronic 3.2 is pretty simple, you swap in a 964 distributor and a splitter for the DME and a custom chip with the new advance curve. Not sure if the splitters are still available, I think it was an Andial product, and pretty sure they are gone.

Twin plugging a given engine and not changing anything else will result in more power. This is because the flame front is ignited from 2 places in the cyl and the 2 flame fronts can more quickly fully consume all the air fuel. This allows you to retard timing and still achieve max cyl pressures. A single pug hemi cyl is a trade off because the plug is so far to one side that the flame front takes significant amount of time to reach the other side of the cyl and thus this requires more ign advance which is not desirable because it tends to fight the up stroke of the piston.

So for discussion assume that the single plugged config at 4000RPMs achieves peak torque at 30 deg advance then the dual plugged config may only need 25 deg advance to achieve peak torque and because it reduces advance by 5 deg that's extra energy that's not spent fighting the piston on the upstroke.

3.2 to 3.4
 

Hi Gamin,

Could you please detail the parts used in your 3.2 to 3.4 conversion...including the cams. did you replace any other parts in the process?
My present set up is a 100 cat and free flow monty mudfler and a 91 Steve W chip on a 87 carrera with 81k

I thought the advantage of ITBs was that it put the throttles much closer to the intake port, thereby reducing the lag created by a large volume of air between the throttle and port in a conventional system. This increases responsiveness.

That is a advantage, but the gain is pretty small compared to swapping to a real high-overlap performance cam.

Bruce Anderson has a dyno chart in his book that shows a 3.2 (short stroke) engine with Webers, cams and exhaust getting about 275HP. You won't get that from slapping a set of Webers on a 3.2, no matter how good the throttle response is.

http://www.shedracing.net/imgmisc/anderson_book.jpg

Ditto

Thanks

Pieces of industrial art do that to you. When I visited the NYC MOMA a number of years ago I was both surprised and excited by finding a Pinnafarina designed Alfa blocking the doorway.

That said, my '86 makes 215whp with no more than a cat delete and Steve's chip. I don't even know if altitude was taken into account on the tune of the chip, but the car lived in SLC before it came her. That is SAE corrected since I am at 5000ft, and on what is locally known as a heart breaker dyno. The Subaru in my signature make 225chp, but only hits the dyno at 150. Apples and oranges though since the AWD driveline loss in my car is more significant than a 911.

But just from the beginning there is a lot left on the table. As others have said in this thread, do you want to break into your engine itself? If so, then your goal is easy, cams, pistons with different profiles to account for your choice of fuel delivery and carbs or ITBs. Which one of the latter is up to personal preference. Twin plug is Cool, but is at least another $2-2.5k on the build and not required for your goal.

maxdude....i had really high hopes for the efi/itb system..and there were some great threads here on pelican on precise installation and relative ease of tuning. (see Trog on here, and JJ from canada)so i went with it... to be specific mine were 46 pmo itbs with Tech3r Electromotive twin plug Crankfire ignition with all the fancy sequential cam sensors and a top notch AFR meter. This was for a dedicated hotrod DE car. Simply put : it sucked for 1.5 years. I spent thousand of dollars on tuning dynoing, each tune could not rid the system of a midrange miss, that occured at inopportune times... like on the high banks of daytona, or say, the gurney straight at sebring...both butt clenching misses... so you end up "driving the mis"! it was almost like ectopic induction of a rev limiter, whenever the system felt like it.. moreover the tach signal was also intermittent .. unbelivable....we finally got it fixed by flashing the whole unit.. anyway i switched to carbs also for getting placed in a vintage class.... btw everytime i took it to a tuner i got the screw eye and the comment...." electromotive huh...." not disparaging this jus sayin... btw the msd boxes with a dizzy and carbs is bum fock simple, and i have gained throttle response, and likely hp... will dyno sometime this winter at sebring..