What engine for my RSR?
 

I'm planning to convert my perfectly good '86 Carrera into a stripped down '73 2.8 RSR replica, as so many others have already done. I'm planning to use the stock tranny, brakes, and suspension from my car, which have all been recently rebuilt. The only thing I need to do is body work, paint, and engine.

My engine budget is $15k plus the 3.2L that I have to start with. I can sell it and start with something else if needed, but whatever I end up with I want to be able to do the disassembly/reassembly myself using Wayne's book, if possible.

This will be a street motor, and needs to pass Colorado emissions (horrors!) and last at least 50k miles before needing another rebuild.

So, what's the best motor to build for this car, considering I don't know much about engines aside from what Wayne tells me in his book, and that I want at least 250 flywheel hp when I'm through?

P.S. I'd love to send the motor to Steve Weiner, but that would probably blow my budget out of the water, and besides, I want this to be as much of a DIY educational project as possible. My mind remains open, however.

P.P.S. I'm doing my diligence with the search button, but I can't search on 3 character terms like RSR, 2.8, etc.

Search me or "catca" (my old user id) on the engine forum for a decent 3.4 build or dfink here on this forum for a similar build. These will give you an idea of what others have done. Look around on the engine forum, lots of great motors have been built over there....

Gogar, make that a 2.4S and I might pause to think about it...

How about this?

-Wayne

http://forums.pelicanparts.com/uploa...1228984793.jpg

If you are in the Denver Metro you could get a PO Box in Larimer, Grand or Elbert and register your Pcar there to avoid the Colorado E-test. I'm sure several other surrounding county's don't have emissions either but I know those three don't.

:confused:

OK, Wayne..........

Tell us about this 3.6 motor w MFI....

Its sure not a 79 911.

Len

:)

Sell 3.2 + $15K gets you into a nice 3.6 conversion.

Porsche factory werks prototype engine created for Vasek Polak's 908 chassis. The only one like it in the world...

-Wayne

get your self a 3.6 - 4.0

- '94 964 3.6 > 250hp
- '95 993 3.6 > 270hp
'96 - 98 993 3.6 > 280hp
3.8RS > 300hp
4.0 > 330hp
all but the last will be smog legal

That's what I was thinking. A stock 3.6 would do the trick nicely but I don't know if $15K will leave you anything for the bodywork and that's probably true no matter what engine you go with other than the 3.2 you already have.

Financially, would you not be better starting with something like this:

http://forums.pelicanparts.com/porsche-cars-sale/438950-1974-911s-993-3-6l-engine-track-car-sale.html

??

If I was in your shoes I would go the same route as Jeff - but maybe make a 3.7 out of it with LN Engineering Nickies. I always like the idea of a full rebuild vs an unknown used engine.

or this

http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/445156-3-6l-race-motor-350hp-turn-key.html

$15k is just the engine budget. An additional $15k for chassis straightening, rust repair, panel fitment, and paint.

One thing that doesn't turn me on is the idea of a 3.6 swap. I know it may be cost effective, but I really don't want to buy a solution - I want to build one. This is going to be a fun project. I don't want to just write a check.

Surely I can coax 40 more hp out of a 3.2 without spending the entire budget...can't I?

I already have a Wong chip and exhaust on it. If I added 964 cams and a custom Wong chip, how much more would that get me? Suppose I rebuild it with 98mm jugs in addition (single plug 3.4, keep the Motronic). Now how much?

I think Jeff can tell you what you'll get from a 3.4.

For comparison, here's my 3.4, in blue, compared to Ralph's 3.5, in red, compared to a bone stock 88 3.2 with a euro premuffler and stock chip, in green.

http://forums.pelicanparts.com/uploa...1141874787.gif

Now Jeff's 3.4 with ITB was a large step above these. You can run wilder cams with the ITB's. My 993 ss cams are about as hot as you can go and still idle with motronic.

Wayne, you're one of the guys I was hoping to get some useful advice from. :)

Hmm - after I reread - and the need to pass colorado emissions - I'd follow Bill V's advice - he's spot on. I'd sell your 3.2 - I'd buy a 3.6 core engine and rebuild it to 3.8 or 4.0 specs. You won't be able to go too hot on the cams. Stay with the stock engine management. That should get you past emissions. You'll be pushing your budget though.

I'd stick with your 3.2. I assume you already have done the cat bypass, if not do that. Then add the 964 cams and updated Steve W chip. That won't gain you much more HP, maybe 5 or so, but you will now get a lot more off the line grunt. When I rebuilt my 3.2 I went with SSI's, 964 cams, chip and muffler and it is nice and strong off the line all the way up to redline. Stripping you car of weight will just make it more of a beast.

Yes, I will definitely be reading Jeff's thread on his rebuild.

I love ITB's. I'd love to build a 3.2SS with PMO ITB's, twin plug, TEC-3, and S cams. If I can do that without busting my budget (including professional tuning), I wouldn't hesitate. Could an engine like that pass an emissions test?

Call Orin @ 303.789.2545. He is great at getting hotrod engines through emissions.

A very sensible suggestion Kurt. And if I swap my 8:31 ring and pinion for a 7:31 in addition to your recipe, that would make it quicker still. Something to think about, as that would certainly save some money and the hassles of trying to implement something more exotic.

Way too many options!

Is mechanical fuel injection particularly expensive or challenging to implement? Should I even consider it?

Get Bill V to comment on gear ratio's....and brakes.

MFI is tough because it runs off a pump that is driven by a belt attached to one of the cam shafts. Obviously the non MFI motors do not have the attachment on the cam shaft. It can be added...its only money. There used to be a guy on here who had a 3.0 with MFI. I think he sold the car..very dreamy.

Also, I think the modern FI is such a huge step up in tuneability and ease of operation you would be better going after the "look" with some tall trumpets but actually using sensors and computers to fire the fuel instead of cam driven.

careful on the 7:31 . the torque and use/ abuse ? will wear it out quickly. Better bet to keep the 8:31, wevo or similar billet side plate, and go with shorter gear sets.
we have had several clients (inc myself) bust or wear out 7:31's in high torque/ hp cars
db

I posted this on another thread but hope this will help. 3.2 in my SC. I can tell you the driveability, usable torque, etc. is great.

http://forums.pelicanparts.com/uploa...1229032544.jpg
http://forums.pelicanparts.com/uploa...1229032555.jpg

1986 Euro Carrera motor rebuilt by Chris Powell of Chris' Foreign Auto in Bellevue, WA. Dyno tested at 210 SAE HP at the rear wheels. Adjusting for drivetrain losses and converting to DIN gives 255 HP at the crank.
Rebuild details: 10.3:1 compression ratio Euro pistons and cylinders; low mileage 964 turbo crankshaft; 993 cams; cylinder heads ported and polished by Chris; case webs relieved for windage; ARP rod bolts; rods rebushed, balanced and resized end-for-end; pistons weight balanced; crank, flywheel and pressure plate balanced; throttle body bored out 3mm; intake manifold “ported” for larger throttle body and polished; injectors rebuilt and blueprinted; adjustable rising rate fuel pressure regulator; SSI headers with fully functional heat exchangers; new CV joints and axle shafts; Monty dual outlet muffler; Autothority chip customized for application.

Some would probably argue the calculation on the HP conversion. I don't know enough about it to comment. This motor came with the car.

If the criteria is to build your motor yourself, I would think this could be the way to go.

Add a turbo, and welcome to the dark side!

Or simply buy a C2T engine, and add exhaust and wastegate spring, an Andial enrichment system and you easily will have over 400 of reliable HP. Easily done for less than $15k.

buy the car on ebay and sell your car . that is a bargain!

My favorite is the 3.2L to 3.5L conversion carrera3.5L documented some time ago. California street car with 246 whp and 224 lb-ft of torque.

http://forums.pelicanparts.com/porsche-911-technical-forum/186906-3-2-3-5-part-ii-8.html

Will that intercooler fit under the duck tail?

Good tip, thanks Dave. I've thought about shorter gear sets and it would be nice to shorten the big RPM drop between 1st-2nd. New gears are more expensive up front but I'm sure it's a better solution.

Too bad you guys aren't located closer to me. It would be great to have TRE involved in the project.

Dude, I would be all over this... http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/445936-964-3-6-engine-sale.html

If, when, I do it again, I am going for more displacement. I am still toying with the 3.7 idea this winter but time is an issue for me.

From scratch, I would build a 3.9 or 4.0 with ITB's.......

Cheers

Yeah, that's tempting, and right here in town. It just isn't what I want though. Half of the point of my project is to learn about engines by rebuilding one. The other half is to end up with an engine that is the right character for a vintage race car replica.

I would like to have Todd at Protomotive convert the Motronics to a vac sensing system that would work with a set of Individual Throttle Bodies. Set it up with PMO units and get a set of early air cleaner tin to make it look stock.

Get a twin plug retro distributor and an Andial signal splitter.

Maybe some and amber motor shroud.

Could bore the cylinder, have them plated, and use J&E's unless some 3.4 or 3.5 MFI or Carb P&C's could be sourced.

I'd also spend some of the money on the trans for some short gears. :D

This one gets my vote: http://forums.pelicanparts.com/showthread.php?t=445156

And after you buy it you'd even have some $$$$ left to play with...

Ask TRE about the RS clone motor they are building. It's probably a bit short on HP, but authentic for an RSR type toy.