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914World.com _ 914World Garage _ Which motor for future turbo?

Posted by: sgray944t Mar 31 2005, 09:53 PM

Well first I will introduce myself as this is my first post. I live in Raleigh, NC and have decided to build up a 914. My dad has lots of experience with Porsches of all types and suggested a 914 as a relatively simple and very fun car. I have been reading this site for a few weeks religously trying to learn everything I can. Im buying a 914 with the intent to swap a 911 motor in it. I am mainly interested in the 3.0 or 3.2 conversion, eventually to turbo. This is where my question comes into play. I have read Iamchappy's thread about turboing his 3.0 motor, and it seems like the 3 liter has no problems accepting boost. However I havent come across anything about turboing a 3.2. Is there any mechanical reason for this, or is it just something no one has documented? The reason I ask is that I am probably going to install the motor in its NA form first, then gather the parts for turbo over time. I think the higher hp of an NA 3.2 would hold me over until its time to turbo, however if turboing 3.2 motors is not ideal, and the 3.0 is a better forced induction motor, I would rather stick with it. My final goal is somewhere around 300hp give or take. At this point I'm thinking that the 3.0 is the better choice because its been turbocharged more often than the 3.2 and therefore I will have more support when problems arrive. Im also fairly sure the 3.0 can give me the power goals I'm looking for relatively easily. But please enlighten me, Im still learning about this 914 thing so I can use any comments you might have. Thanks alot guys!!!

Posted by: 9144guy Mar 31 2005, 10:06 PM

id have to look at the spec book but i( think) 3.2 l were in the c2/c4 modles and had alot of oil problems, we at the shop have pulled apart 6 c2/4 motors for base gaskets and other seeps, done 3 993 motors for clogged air induction cloges in the heads ,i could findout more, let me know

Posted by: sgray944t Apr 1 2005, 05:43 AM

Werent the 964s 3.6 liter? Im not really interested in putting a 3.6 in the car becuase of the added work to make it fit. Plus it raises the cost quite a bit.

Posted by: Brando Apr 1 2005, 11:33 AM

The best way is to go with a 911SC 3.0 engine. It is essentially the same as the 930 (1970's 911 tubo) except naturally aspirated. All of the internals are made to work with turbo applications. If you're hankering for a 3.2... with the investment if finding a 3.0 without broken headstuds (~$3000 for a new top end, average) you can get a 3.0 case bored out a bit and then move on to the turbo applications later. You can easily get 250 out of a 930 case with forced induction.

The C2s and C4s of the 80s as stated use a MAF system and have more electronic systems than you want to deal with. More hassle than it's worth for a 3.2L motor. A 3.6L motor is better and worse. They make about 325 at the wheels but are so electronically managed you'll pull your hair out making it work.

This is before making a G30 or G50 trans fit in there. See where I'm going?

Best results would be
3.0L case, punched out to 3.2, turbo'd with 930's induction and exhaust systems.

Posted by: Brando Apr 1 2005, 11:37 AM

The question I have though, is how much horsepower do you need in a 914? The car's only about 2000lbs on the heavy end. Even with a moderate 200hp 6cyl engine you've got 10lbs:1hp. That's a nice power to weight ratio. With a turbo you'll accelerate a hell of a lot faster. Then you can spend your extra pennies on some nice big 23mm swaybars up front and in back. I'd suggest with that much power getting a roll-cage bolted or welded in there.

Posted by: ArtechnikA Apr 1 2005, 11:49 AM

QUOTE (Brando @ Apr 1 2005, 12:37 PM)
with a moderate 200hp 6cyl engine you've got 10lbs:1hp. That's a nice power to weight ratio. With a turbo you'll accelerate a hell of a lot faster.

exactly.

well, sorta.

the turbo motor is heavier, the beefier transmission and driveline parts needed to handle the power are heavier, the bigger brakes you'll need are heavier, the cage you'll want after you scare yourself silly the first time is heavy, and before long, you're back to the 10 lbs/HP you couldda started with...

turbos are fun (and yes, i want one...) but you're never able to get away from the careful balancing act necessary to keep you from going backwards - at great cost...

Posted by: street legal go-kart Apr 1 2005, 12:06 PM

buy a 2.0 driver and drive it for a year , go to a few scca autocross events and then revisit this topic.
Even a 3.0 non turbo 914 is a LOT of car. The 2.0 will be about 1/3 the cost of the setup you are thinking about.
Welcome to our madness

JT

Posted by: nebreitling Apr 1 2005, 12:44 PM

QUOTE (street legal go-kart @ Apr 1 2005, 10:06 AM)
buy a 2.0 driver and drive it for a year , go to a few scca autocross events and then revisit this topic.
Even a 3.0 non turbo 914 is a LOT of car. The 2.0 will be about 1/3 the cost of the setup you are thinking about.
Welcome to our madness

JT

get a taste for it first -- this will sustain you while you put the minimum $15-20k into your project.

i'd love a big turbo'd six -- i say go for it! -- just look before you leap!

and welcome!

Posted by: Mueller Apr 1 2005, 12:49 PM

QUOTE
The C2s and C4s of the 80s as stated use a MAF system and have more electronic systems than you want to deal with. More hassle than it's worth for a 3.2L motor. A 3.6L motor is better and worse. They make about 325 at the wheels but are so electronically managed you'll pull your hair out making it work

The C2 (mine is a 91) and C4 didn't start until late '89, they are 3.6 liters and are popular swaps into early 911s...the wiring issue has been resolved with a few companies making kits...the biggest pisser of a 3.6 if want to turbo it is the high compression as delivered from the factory, it is in the 11:1 range...they do have twin-plugs right from the factory so that is a positive

The 3.6 motors from the 993 would be nice, that is when they started using hydralic lifters so no more valve adjustments, that is a good thing.....

Posted by: Brando Apr 1 2005, 06:34 PM

QUOTE (Mueller @ Apr 1 2005, 10:49 AM)
The C2 (mine is a 91) and C4 didn't start until late '89, they are 3.6 liters and are popular swaps into early 911s...the wiring issue has been resolved with a few companies making kits...the biggest pisser of a 3.6 if want to turbo it is the high compression as delivered from the factory, it is in the 11:1 range...they do have twin-plugs right from the factory so that is a positive

The 3.6 motors from the 993 would be nice, that is when they started using hydralic lifters so no more valve adjustments, that is a good thing.....

i missed a 'late' between "in the" and "80s".

Up until 89 they still used the 930. Strongest of them all pre-existing the 964.

The 993 and 964 use the same block (964). Only difference is the 993 has air injection into the exhaust, later got varioram and variocam. Turbocharge that and WOAH you'll need new undies. Benefit of those 2 is that they did make a turbo 964, and did make a turbo 993 (equipment already exists).

Fun with the 964 and 993 include: Once the air injectors on a 993 get clogged you get to have a lot of fun not passing smog with a check engine light and a new top end. Or when the drive belt for the twin distributors goes bad. Or when the speed reference sensor goes bad (wont run right). Or the cold-air intake sensor goes awry. Oh wait, that last one's only on 996s and boxsters.

Posted by: sgray944t Apr 1 2005, 08:34 PM

I think I got a little too hasty thinking about a turbo six cylinder 914. The thought of it just got me going without really considering all the factors. I WILL have a turbo 914 eventually, but I think I am going to start out with an NA 3.0 and rebuild it myself. Im not so much into the swap just to have and drive, I really want the experience of building up the car. So now my plan is just get the 3.0 in there, enjoy it for awhile, and add turbo way down the road when I have all the parts collected. With a 2300lb weight and a 200hp 3.0liter I should have a weight:power of about 11.5 to 1. That seems pretty quick and capable of running with most cars on the road, as well as out handling them by a large margin. Thanks for all the help and hopefully this thread will be ressurected in a few years when turbo time comes!!

Posted by: Series9 Apr 1 2005, 08:55 PM

QUOTE (Brando @ Apr 1 2005, 05:34 PM)
Only difference is the 993 has air injection into the exhaust..

There are quite a few differences between the 964 3.6 and the 993 3.6. The 993 engine is a much better motor, IMHO.

I have a Euro 993 3.6 which has no air injectors and has solid lifters (something I was interested in having).

Among other things, I enjoy a MAF Motronic system. The 964 is not MAF based.

There's also a significant difference in HP between 964, 993 and Varioram.

Posted by: Brando Apr 1 2005, 11:09 PM

Thanks for clarifying 914RS...

Although, if the 964 is not MAF based... what would it be then? Has volumetric metering of air:fuel and a computer that runs through fuel maps depending on your driving habits. Or is a MAF system only designated to those with manually controllable timing and air/fuel mixture?

Posted by: Series9 Apr 2 2005, 03:29 AM

QUOTE (Brando @ Apr 1 2005, 10:09 PM)
Although, if the 964 is not MAF based... what would it be then?

Your question makes almost no sense.

The 964 3.6 is based on the L-Jet flapper-box system. It's the same as the 1.8 FI, before L-Jet was digital.

Posted by: joea9146 Apr 2 2005, 05:47 AM

Building the Turbo has a big cool factor, but to build it on a 911 3.0 can get very pricey.
Most 3.0 are close to 25 years old so figure on having to rebuild the motor
which gets pricey, than all the Turbo stuff you need to fabricate..... more $$$
If you do it right you will eaisly spend 10k - 12k.
If you are looking for lots of power and grunt just drop a stock 3.6 motor
into the 914.... lots of power and reliability, and will cost you less in the long run.
Also Big Cool Factor
If you still want to turbo a 3.0 find the 3.0 that has the lower compression pistons
I believe the lower compression motors are 8:1, Turbo applications are better with
Lower compression

Posted by: sgray944t Apr 2 2005, 10:33 AM

Im rebuilding the motor either way so the age of it does not really concern me that much. I was mostly interested in the 3.0 for turbo becuase the CIS injection easily compensates for boost, and becuase of the available support from members who have turbo 3.0s. Not to me mention there was actually a turbo kit available for the 3.0, so I know it will work relatively simple.
Does any have a diagram or explanation page or something on how the CIS injection works? Im buying a book today on the 911 motors but Im not sure if it explains how the system works.

Posted by: ArtechnikA Apr 2 2005, 10:48 AM

QUOTE (sgray944t @ Apr 2 2005, 11:33 AM)
Does any have a diagram or explanation page or something on how the CIS injection works?

there are pages out there, grassshopper, make Google your friend.

here are three good books:

Bosch Fuel Injection & Engine Management
How to Tune & Modify Bosch Fuel Injection
Solving Bosch Continuous Injection System Problems

available http://www.pelicanparts.com/catalog/shopcart/911E/POR_911E_documt_pg2.htm#item12 among other places.

Posted by: sgray944t Apr 2 2005, 03:18 PM

Well I just bought Bruce Anderson's book and I did in fact see the "How to Tune and Modify Bosch Fuel Injection" right next to it. Does this book have the same system that comes on the 3.0l in it? The link says K-jetronic and L-jetronic which I've heard on this website before but Im not sure what motor it goes with. Ill have to go look through the book and see whats in there.
Thank you master

Posted by: Mueller Apr 2 2005, 03:25 PM

QUOTE
Is this book Porsche specific?

no, not really, but CIS is CIS, does not matter what vehicle it is from......just so you know, custom fabrication is going to be needed, there is NOT a kit to install a turbo into a 914 specifically with a /6 motor (or a /4 anymore)...so don't expect to just be able to look in a catalog, buy a part and just bolt it right up to the car.....

I have this book, as well as the others mentioned, you can never have enough reference material .......

Posted by: ArtechnikA Apr 2 2005, 03:32 PM

QUOTE (sgray944t @ Apr 2 2005, 04:18 PM)
..."How to Tune and Modify Bosch Fuel Injection" right next to it. Does this book have the same system that comes on the 3.0l in it? The link says K-jetronic and L-jetronic which I've heard on this website before but Im not sure what motor it goes with.

from the descriptive link at the Pelican site:

"Specific testing and tuning guidelines are provided for many foreign cars."

914 1,7 and 2,0: D-Jet
914 1,8: L-Jet (very similar to the system used in 928)
911 T from 1973.5, and all 74+ through (IIRC) 1989 including 911SC: K or KE - Jetronic - also known as CIS or CIS-E.

CIS - Continuous Injection System. K-Jetronic - K is for Kontinuous.

at some point Porsche switched to DME / Motronic

a good websearch for CIS Injection and/or K-Jetronic will turn up many references; adding 'Porsche' to that search will narrow it down. many European cars use one of the Bosch injection systems, and many of the Asian cars use systems developed by or licensed from Bosch.

i know there's a 911-specific site on CIS troubleshooting and testing, but i haven't tracked it down yet. note - most of the stuff you will find in a 911 context involves troubleshooting and fixing stock systems - there aren't a lot of modification references, because CIS is rarely used in a performance application. Porsche used CIS on the 934 only because the FIA rules made them do it.

Posted by: sgray944t Apr 2 2005, 04:02 PM

Sorry for the repetitive questions, its alot to take in.

Posted by: sgray944t Apr 3 2005, 03:49 PM

So what about the possibility of a 930 motor? Would it fit just the same as another 6 or would it not fit at all becuase of the turbo location?

Posted by: Mueller Apr 3 2005, 03:57 PM

QUOTE (sgray944t @ Apr 3 2005, 02:49 PM)
So what about the possibility of a 930 motor? Would it fit just the same as another 6 or would it not fit at all becuase of the turbo location?

you'll have to play with the exhuast and location of the turbo.....the motor will bolt right up, but the turbo/exhaust will need to be modifed/moved around....not that big of deal, mount the turbo inside the engine compartment or hang it out in the back ...it's been done both ways...

Posted by: sgray944t Apr 3 2005, 05:26 PM

You dont by any chance know of a webpage of someone who has done this do you? I searched google and couldnt find anything.

Posted by: Mueller Apr 3 2005, 05:51 PM

http://www.914world.com/bbs2/index.php?act=ST&f=2&t=27690&hl=turbo

http://www.clewett.com/photos/914/914page.htm

Posted by: Qarl Apr 3 2005, 07:18 PM

Its not as expensive as others would have you believe. If you can do a little welding or know someone who can, it can be done for less than a PMO carb conversion.
The silicone intake boots that replace the stock rubber one that ties the cis intake plate and the throttle body are the tough ones, I am considering making some using silicone and aluminum sometime in the future, The ones I am using are from a BAE kit, if you can find the old bonnets from a kit, the rest is actually pretty straight forward but you will have to do your own fabricating like I have.
Even a low boost 3.0 sc engine is quite a thrilll.

Posted by: Qarl Apr 3 2005, 07:23 PM

Oops, I am logged in as Qarl, This is IAMCHAPPY on Qarls computer, Oh by they way just had a ride in the Lotus, very, very cool, reminds me of the car scene in a clockwork orange.
Talk about tight.

Posted by: sgray944t Apr 3 2005, 08:31 PM

Unfortunately I dont think BAE is in buisness anymore, so I would need to get custome exhaust manifolds if I was using the 930 motor. It seems like that might be easier than trying to boost an SC engine, since I will only need to reposition the turbo and not fabricate intake and exhaust stuff for the SC.

Posted by: Mueller Apr 3 2005, 09:19 PM

QUOTE
Unfortunately I dont think BAE is in buisness anymore, so I would need to get custome exhaust manifolds if I was using the 930 motor. It seems like that might be easier than trying to boost an SC engine, since I will only need to reposition the turbo and not fabricate intake and exhaust stuff for the SC.

I'm 99% sure both cars above are using the same exhaust that you'd run on a NA motor...nothing too custom....

The only "custom" part of the exhaust is the tube that connects both banks together to the turbo.....

Posted by: Qarl Apr 3 2005, 09:23 PM

Its not that easy with a 930, you still will have to fabricate intake plumbing and exhaust, and you will need to fiqure out a flywheel that will work, The 930 Cis uses 2 fuel pumps, it is not a straight forward install but nothing like this is. I picked up a used BAE kit when I started my project but if you could make up something to work like the BAE bonnets the rest is not to diffiicult to assemble..

Posted by: Mueller Apr 3 2005, 09:25 PM

QUOTE
Its not that easy with a 930,

won't the NA parts from an SC bolt to the 930 block or are they that much different??

Posted by: ArtechnikA Apr 4 2005, 05:20 AM

while y'all are working on intake and exhaust manifolds (stock HE's won't live long with the heat, and headers although better, especially thermal coated, are still highter-gauge and different metal than the 830's...) don't forget the other parts that made the Turbo Carrera special -- the turbo scavenge oil pump that allows the low mounting position. the factory used the same nutating oil pump that once powered the torque convertor for the SportOMatic, driven from the and of a camshaft like an MFI pump.

when you go deciding where you're going to be mounting turbos, give some serious consideration to how you're going to get the oily foam out of the bottom of the turbo and back to - where? sump? oil tank? pick a place ...

Posted by: sgray944t Apr 4 2005, 05:33 PM

Well when I get around to it Im going to have to just make a copy of someones BAE kit for the SC motor. Although a 930 motor would be really neat, the special items it has would make it a far more complicated swap. Plus I kind of like the higher compression ratio of the SC motor vs. the 930. Although 20 years ago a low low c/r was necesarry, I think running 8-9psi on an SC motors c/r would be more fun than a 930 motor due to the off boost response.

Posted by: Qarl Apr 4 2005, 06:10 PM

This post is by IAMCHAPPY on Qarls computer,
sc cams are one of the upgrades they do to 930 engines, my next upgrade will be changing out the piston and cylinders to a more boost tolerant combo, but I have high boost asperations with all the other nessescities in place.

The oil scavenge pump was a pretty easy install on the back of the cam on the sc engine, and the pumps can be pickup up pretty cheap, I paid 50.00 for mine then purchased two fittings from Pegasus from metric to 8an.

the sc engine really runs great at 9lbs with fuel enrichment via a 7th injector and has been proven to be very reliable over many years of hard use.

Aso the 3.0 and 3.2s are easier and less expensive to find in good condition than a 930 engine.

Posted by: Cap'n Krusty Apr 4 2005, 06:17 PM

We need to get some semantics dealt with here. An SC IS a 930 motor. The 911 Turbo motor is based on a 930 case, as is the 911SC, with different crank, rods, pistons and cylinders, cams, and a lot of other stuff.

If you want to put a basic 911 motor in a 914 chassis, especially a big motor, you will need to gather together parts which can (and usually do) cost as much as the motor. You'll need to reinforce the chassis as well. You can EASILY get into a car with a 911 engine swap to the tune of $12-15K (including the cost of a nice roller) without labor. A lot of us have done these, and most of us have been amazed at how quickly the nickel and dime stuff adds up. As others have said, you'll need to do the brakes, and the tranny may not be sufficient to handle the increased torque of a big motor. Putting a turbo into the equation might well double the costs.

I've done a a conversion with a 2.7 RS style MFI motor and 79 turbo brakes, with 7s and 8s and SC rear flares. We're guesstimating 275 HP and the car was scary fast, without any of the heat and throttle lag problems of a turbo. By the time the car went from a 1.7 to a 2 litre, then a 2.4T, then the 2.7, including the body and paint, sound system, and interior, the guy had spent $40K. It was almost as fast as his SCCA GT2 car.

My suggestion would be to find a car someone has already done (and done right) and drive it for a while. The Cap'n

Posted by: Qarl Apr 4 2005, 07:25 PM

This is IAMCHAPPY again not Qarl.

There is some truth to what the captn says, but if your patient and shop around it can also be done on a budget. I have about 12,000 total into mine and it still needs a paint job and some new trim pieces, but the high performance parts and additions on my car are as long as my arm and it scares me to think of what it would of cost me if I hadnt shopped around, and pieced it all together.

Posted by: sgray944t Apr 4 2005, 09:01 PM

I know the SC and 930 motor are based off the same blocks, I was just using those references to quickly differentiate them in a way I thought people would understand. I understand that these conversions can get very pricey but Im not really concerned with that. That being said there is a limit to how much I can spend on the swap itself, but I dont see the necesity in spending 12k on the swap alone unless your buying all new parts at dealer prices. Im not trying to turn this thread into a pricing one becuase even being here only a few weeks I have read plenty. Im more concerned with getting the right parts to build a 250hp NA motor and then having the later ability to turbocharge it without having to swap all the internals out. I think that is doable on a 3.0liter street/track motor without THAT much trouble. If I'm wrong please correct me.
By the way thanks for responding guys this is the most help I've ever gotten on a forum, even ones I have been a part of for over a year!!

Posted by: Mueller Apr 4 2005, 09:10 PM

QUOTE
I think that is doable on a 3.0liter street/track motor without THAT much trouble.

it purely depends on your skill and your definition of trouble

some people are very skilled with the needed resources to get the job done, some are very skilled but do not have the needed resources but figure out a way...then there are some people that shouldn't own a screwdriver since they are not sure which end to use