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924/931/944/951/968 Forum Porsche 924, 924S, 931, 944, 944S, 944S2, 951, and 968 discussion, how-to guides, and technical help. (1976-1995)
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Old 09-03-2014, 02:25 PM
  #46  
theamsoilguy
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The guys at Renegade hybrids can get you a lot of info ( and conversion parts ). My car was built with their parts. The previous owner put in a hydraboost, and Renegade told me I probably wouldnt be happy on the track, they were right and Im installing a tilton assembly now. But Scott is a great resource as he has helped many owners get their cars done. Plus they have track experience with converted cars.
Old 09-03-2014, 05:56 PM
  #47  
Forty-six and 2
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The Ls swap would make for a fun car, but it seems to be a costly conversion compared to other options.

I personally like forced inducted smaller motors. Vw and Audi have plenty to choose from, and are easily adapted to the 944's powertrain. 400+ whp is an easy mark to hit with their 4/5 cylinder motors. A low mileage 2.5l 5cylinder can be sourced from the newer Jetta/Rabbit line for $500! Simply bolt on a turbo setup running 20 psi, on a 100% stock motor, will yield over 500whp. Build a cheap 2.0 16vt, and have a high revving 400-500 whp powerplant.

I come from the VW/Audi world, so my mind will always lean towards their motors. They are fairly cheap, can be made very reliable, and are capable of plenty of easily made power.

Most people immediately turn a deaf ear when VW is mentioned. Take the time to watch a few youtube videos, and you just might be impressed by what they can do. I will be gong the VW route when the time comes...
Old 09-03-2014, 06:22 PM
  #48  
Jfrahm
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Which VW motors are easily adapted? Transverse bunny motor?
Old 09-03-2014, 06:54 PM
  #49  
Forty-six and 2
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ALL Vw and Audi 4 and 5 cylinder use the same bellhousing. From what I have read, the 931 bellhousing bolts to it and the 944 clutch fork is still used.

Last edited by Forty-six and 2; 09-03-2014 at 08:24 PM.
Old 09-03-2014, 08:02 PM
  #50  
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More indepth searching lead me to this build..

http://forums.pelicanparts.com/porsc...nightmare.html

Not exactly simple, but fairly basic skills can make it happen. The bulk of the work is for two torque tube and bellhousing adapter plates. The remaining work is all straight forward.


This is a old Audi 5 cylinder, which would be the best option for high hp forced induction, but are getting hard to find.

http://www.944-20v.nl/

Last edited by Forty-six and 2; 09-03-2014 at 08:24 PM.
Old 09-03-2014, 10:13 PM
  #51  
arthropraxis
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Originally Posted by MAGK944
Greg Sloan did one a few years back, ISBN 978-1-4276-4406-0 2009 148 pages, though it's mostly out of date now and better info is available online. Here's my copy:

Just in case someone missed Doc's post, do some research on the author before sending your money for this book.
Old 09-03-2014, 10:46 PM
  #52  
JJR512
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Originally Posted by Forty-six and 2
The Ls swap would make for a fun car, but it seems to be a costly conversion compared to other options.

I personally like forced inducted smaller motors. Vw and Audi have plenty to choose from, and are easily adapted to the 944's powertrain. 400+ whp is an easy mark to hit with their 4/5 cylinder motors. A low mileage 2.5l 5cylinder can be sourced from the newer Jetta/Rabbit line for $500! Simply bolt on a turbo setup running 20 psi, on a 100% stock motor, will yield over 500whp. Build a cheap 2.0 16vt, and have a high revving 400-500 whp powerplant.

I come from the VW/Audi world, so my mind will always lean towards their motors. They are fairly cheap, can be made very reliable, and are capable of plenty of easily made power.

Most people immediately turn a deaf ear when VW is mentioned. Take the time to watch a few youtube videos, and you just might be impressed by what they can do. I will be gong the VW route when the time comes...
It is good to have options.

I like that the VW engine is a German engine; all else being equal, I'd prefer to have a German engine in a German car. But all else is not equal.

How does the reliability of 2.5L five-cylinder engine with 20 psi of boost compare to the reliability of a 5.7L (or 6.0L, or 6.2L, or 5.3L, to pick the four most common LS engines used) V8? I ask because the 2.5L 5-cylinder engine was not turbocharged in its original application, and looks like it has either a 9.5:1 or 10.0:1 compression ratio. Then you're going to add 20 psi of boost, which is a lot (by "a lot", I mean more than the typical boost levels of stock-turbo motors) even for an engine intended to be turbocharged. How will this affect the long-term durability of the engine?

Reliability is a big factor for many people choosing to do a swap. Most people will probably point to the extra power as their primary reason, but I doubt many would do it if the replacement engine needed just as much maintenance as the engine being replaced. I could be wrong, but I feel like asking this 2.5L 5-cyl to make 400whp is stretching the boundaries of what its reliably capable of, whereas an LS V8 would yawn if you ask it for 400whp.

My next concern is the size of the engine. With 2.5L spread between five cylinders, each cylinder is small, which means inherently low torque and needing lots of revving to get usable power. The turbo will probably help more with high-end power rather than low-end power. How is the gearing going to affect getting the usability of the narrow powerband of a small-displacement turbo motor? Motors like this benefit from having more forward gears that are closer in ratio, to keep the engine within its powerband. 944s come with five-speed transmissions. Swapping to a six-speed from a 968 adds additional problems in terms of available gear ratios and other issues, not to mention cost. On the other hand, the LS V8s have a very wide powerband and five gears is fine enough.

Don't get me wrong, I'm not saying this is a dumb idea. As I said from the start, it's good to have options. If you really want to do it this way, by all means, have at it, and let us know how it goes. Maybe you're on to something. But for me, if I could do it tomorrow, I'd go LS V8 all the way. Now, by the time I'm actually able to afford this, if by then you've shown that this is the better way to go, I'm open to changing my path.
Old 09-04-2014, 12:39 AM
  #53  
Forty-six and 2
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Staying true to the German origin is huge to me. Vw is by no means comparable to Porsche, other than it's German roots... It's a personal preference of mine, not one that would lead me to discriminate any other builds.

The 2.5l is a 9.5:1 motor. While that is a the high end compression ratio, in my opinion, is the best for making low boost power. The limitations to the 2.5l motor is it's weak cast crank. It can be swapped for a forged TTrs unit, but that will add $1500 to the build, plus open the "might as well" can, since you will have the bottom end disassembled. Simply back down the boost a few psi, make 50-75 less hp, and regain a bit of reliability.

VAG motors have used factory F.I. for many years. Their build quality is proven to handle plenty more than intended from the factory. Forged cranks have been standard up until recently, and adding other forged components lead to nearly bomb proof reliable motors. The 2.5l holds it's ground with torque, as do other builds. They made nearly all 4 cyl parts interchangeable. With the proper research, cheap gas saving bottom ends can be paired with higher flowing heads, to create a relatively high hp and torque hybrid.

You do bring up very good points about the gear ratios. It will lead me to more gear ratio research. I thank you for pointing that out.

I do have a low mileage 2.5l sitting in my garage, with all of the parts to create a nice turbo motor, it is intended to be used in my Audi. The swap will be completed before committing to the 944 build. I have a 0 mile freshly built 2.2l hybrid 4 cylinder that may make it into the 944, depending on further research. It was built with all forged components and ARP bolts throughout. A past life's build left me with it, and I truly hope to use it. If and when I commit to adapting it to the 944, I will document the steps along the way.

Any type of swap with these cars is impressive, so long as the work is quality. I am by no means trying to discourage or belittle any choices made. Simply adding information, to be taken for what it's worth.
Old 09-04-2014, 11:04 AM
  #54  
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Originally Posted by theamsoilguy
The guys at Renegade hybrids can get you a lot of info ( and conversion parts ). My car was built with their parts. The previous owner put in a hydraboost, and Renegade told me I probably wouldnt be happy on the track, they were right and Im installing a tilton assembly now. But Scott is a great resource as he has helped many owners get their cars done. Plus they have track experience with converted cars.

Why didn't you like the hydra boost?
Old 09-04-2014, 11:25 AM
  #55  
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The issues in the 944 swap are more related to the oil pan clearing the crossmember, the engine mounts, header(s), the brake booster (if you care about power brakes) and the steering shaft.

To make the swap easier you generally want to avoid having to fab a custom oil pan, engine mounts and headers. For the LS swap you can buy what you need and the custom stuff is a bit pricey but not unreasonable. To adapt another motor it appears significant fabrication is usually needed. Most potential swappers cannot fab a torque tube adapter or engine mounts on their own, let alone an oil pan.

Do any of the VAG motor options discussed reduce the need for fabrication?

-Joel.
Old 09-04-2014, 11:26 AM
  #56  
odurandina
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Originally Posted by Forty-six and 2
Staying true to the German origin is huge to me. Vw is by no means comparable to Porsche, other than it's German roots... It's a personal preference of mine, not one that would lead me to discriminate any other builds.

The 2.5l is a 9.5:1 motor. While that is a the high end compression ratio, in my opinion, is the best for making low boost power. The limitations to the 2.5l motor is it's weak cast crank. It can be swapped for a forged TTrs unit, but that will add $1500 to the build, plus open the "might as well" can, since you will have the bottom end disassembled. Simply back down the boost a few psi, make 50-75 less hp, and regain a bit of reliability.

VAG motors have used factory F.I. for many years. Their build quality is proven to handle plenty more than intended from the factory. Forged cranks have been standard up until recently, and adding other forged components lead to nearly bomb proof reliable motors. The 2.5l holds it's ground with torque, as do other builds. They made nearly all 4 cyl parts interchangeable. With the proper research, cheap gas saving bottom ends can be paired with higher flowing heads, to create a relatively high hp and torque hybrid.

You do bring up very good points about the gear ratios. It will lead me to more gear ratio research. I thank you for pointing that out.

I do have a low mileage 2.5l sitting in my garage, with all of the parts to create a nice turbo motor, it is intended to be used in my Audi. The swap will be completed before committing to the 944 build. I have a 0 mile freshly built 2.2l hybrid 4 cylinder that may make it into the 944, depending on further research. It was built with all forged components and ARP bolts throughout. A past life's build left me with it, and I truly hope to use it. If and when I commit to adapting it to the 944, I will document the steps along the way.

Any type of swap with these cars is impressive, so long as the work is quality. I am by no means trying to discourage or belittle any choices made. Simply adding information, to be taken for what it's worth.
terribly sorry to have to break the bad news but,

it seems you skipped the part about getting real about the reliability and longevity
of the late model/recent inclinations of inline VAG/VW/Audi motors.

to our shock and horror, it can be demonstrated; all is not the fine pretty picture after all....

but with due diligence, the truth is out there - awaiting discovery.

but the LS motor = brutal/holy ****/shock and awe/eyes opened/never look back/never going back there again endless amazement.

this fall you can take a ride in mine and call me a liar.


Originally Posted by bumflick
No such thing as too much power IF THE ADDED WEIGHT IS KEPT AT A MINIMUM.
Just not enough tire or brakes or downforce.
you've won the thread.
Old 09-04-2014, 11:41 AM
  #57  
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I've had no issues with the hydroboost on my LS 951 after 4 years of track use. What didn't you like about it?

At the end of the day, I'm not sure any engine swap into a 944/951 is any cheaper than any other swap. They'll all have their associated costs. At least with the LS1 parts are cheap for the engine and power is easily made...
Old 09-04-2014, 01:07 PM
  #58  
theamsoilguy
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Originally Posted by Lemming
Why didn't you like the hydra boost?
Inconsistent pedal feel I am told....Im not consistent enough to really have a handle on that, still need way more seat time. Plus Im not 100% sure its a true dual channel system ( which my rules require ). I hear mine kick in the pump all the time, and I was told that you get different pressures because of this. Its also in the way of the coil packs for me which I have a few relocated because of it.

With a tilton system I can put the pedals where I want which means I can get the seat where I want. This will also get me a adjustable bias valve which I want.
Old 09-04-2014, 01:18 PM
  #59  
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Originally Posted by theamsoilguy
Inconsistent pedal feel I am told....Im not consistent enough to really have a handle on that, still need way more seat time. Plus Im not 100% sure its a true dual channel system ( which my rules require ). I hear mine kick in the pump all the time, and I was told that you get different pressures because of this. Its also in the way of the coil packs for me which I have a few relocated because of it.

With a tilton system I can put the pedals where I want which means I can get the seat where I want. This will also get me a adjustable bias valve which I want.
Well, I'm going the other way, started with a DMC. I loved the feel of the system but the leg pressure required was just too much. If I did not get the ball of my foot on the brake pedal, I had trouble stopping the car in a hard brake zone. This killed my confidence to late brake.

I was not using a tilton pedal setup, I used the stock brake pedal, drilled 3/4" higher, for greater leverage (6:1 pedal ratio, stock is 4.25:1) and a DMC setup positioned in the normal master cylinder spot. I did not go with the Tilton setup for two reasons, first is that you only get a 5.75:1 pedal ratio at most, and the floor mount system put my head directly under the roll bar.

Someone needs to install this setup and let me know how it works http://www.ecihotrodbrakes.com/unive...ke_assist.html
Old 09-04-2014, 01:39 PM
  #60  
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Originally Posted by odurandina
terribly sorry to have to break the bad news but,

it seems you skipped the part about getting real about the reliability and longevity
of the late model/recent inclinations of inline VAG/VW/Audi motors.

to our shock and horror, it can be demonstrated; all is not the fine pretty picture after all....

but with due diligence, the truth is out there - awaiting discovery.

but the LS motor = brutal/holy ****/shock and awe/eyes opened/never look back/never going back there again endless amazement.

this fall you can take a ride in mine and call me a liar.




you've won the thread.

I did comment on the reliability of the mentioned motor... If I were to go into further depth on the subject, I would be talking out of my ***. lol The motor is fairly new, and any current turbo setups may have 60k miles on them. Know VAG F.I. power plants, and their build quality, I can speculate that it would be a reliable motor. I have yet to have first hand experience with the particular setup, so my knowledge is obtained through the research of proven builds. I do have years of first hand experience with other VAG F.I builds, and can say with confidence, they can be built to be reliable. As with any F.I. build, the maintenance must be strict, and you must truly know your setup.

With that being said, the option may not be for everyone, but it is certainly an option worth considering. Yes, the Ls swap is a good one, as I have already said. You do get a fairly high hp/tq motor, with G.M.'s OEM reliability. Personally, I want my German car to stay German, as well as have an F.I. motor. My VAG swap suggestions are simply a quality, reasonably priced alternative to the American V8. A better option, maybe, maybe not. It comes down to the owners preference. The idea of swapping a motor into a 944 seems to be somewhat limited to the GM motor. My suggestion simply adds to list of considerations.

Has anyone mentioned an Audi 4.2l v8?! hahaha


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