Newb 944S LS1 Conversion

Borrow neighbors corded impact ironically called the "nut buster" and that be exactly what it did. Still weird that the guide and exploded pictures show a 17mm bolt and I have a 12mm triple square.... Guess it's a turbo transaxle thing?

Looks like it was red loctited to me so that might explain the crazy amount of force to crack it loose. 

Hope this helps someone.

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You will need an air impact to shock it off. Or something like a new snap on or millwaukee battery impact with alot of torque. That bolt has something like red loctite on it. I had to use my old 1/2" IR air impact.

definitely needs the torque and yes i did see evidence of a red hue so i think it was red loctite.

had a great conversation with Bob from hotrodz of dallas, and he recommended that to put the bolt back in just blue loctite and use the impact again to tighten it up since you can't really torque it up. To keep it somewhat stationary i jammed a bunch of my crappy robertson screwdrivers in the bolt holes of the cv takeoffs to lock it up and get it to stop from moving from loosening.

this is the recommended way to tighten this up no matter whether you have the 17mm bolt as mentioned in the guide or the 12mm triple square like i have which may or may not be a change/difference on the 951 transaxle with LSD

Now that i have my endcap machined its time to put it altogether so i can keep getting closer to first start. made my hit list of remaining things to finish required for first start.

Couple notes that could help people. when it says to use silicone, i used permatex gasketmaker which is good for standing up to oil interface and i ran a thin bead and then used my finger to make an even film such that when it get bolted together it will make a seal and not squish excess into the transaxle.

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i have a plethora of pictures that will help describe the struggle of getting the win on the intake as there are several challenges faced with this and again i have to thank Bob from Hotrodz of Dallas for setting me straight and being able to get what i would consider a reasonable win on take 2 of attempting this.

now as many of us already know different years of LS1, different sizes, and different years of car will have minor differences on fitment which can definitely affect what kind of clearances you are dealing with on making your intake.

challenge number 1 will be based on preference. 1 option is to go into the nose panel with a 120 degree bend that vibrant makes that Bob showed me to which i will edit this post and put the link here as it was a very useful recommend.

However i like to see everything under the hood and get to it easily so i chose what i would call the more difficult route, of getting it to the corner of the fender just in front of the coolant reservoir.

Now by proceeding the latter option there are many many obstacles to get this to work.

First thing you need is a tight 90 to start going towards the fender off the throttle body. You will need either the spectre tight 90 or the intakehoses equivalent; i chose spectre cause it cost me less since i'm in canada and i didn't have to pay a fight of brokerage charges on top of shipping and then more money for how cheap our canadian peso is against the greenback. Now the reason for the tight 90 is that there is just not enough room for a regular 90 and even then you don't have enough with the way the present hood latch sits. Have a look at the pictures below in the multiple following posts since i can only put up 3 pics at a time and you will see the sharpee mark overlay of where i ground out the latch. you need to disconnect your hood release cable so you don't accidentally cut this and i would recommend several iterations of passes so you don't mess with the riveted nature of how the latch will naturally perform. you still want this to work and not mess it up. File all the grinded edges so its not trying to puncture your tight 90 when it goes on cause if it's like mine it's probably going to be dimpled by the hood latch a bit permanently. If you get a clearance here so it remains undimpled then you have done better than I and good job but I was a little timid about messing up the latch so I only went so far.

Here's where more forks in the road come. I went down from 4" to 3.5" by sleeving a 3.5" coupler into the 4" because my MAF is 3.5"; if yours isn't you may do differently here but going down to 3.5" gets you some very vital and necessary clearance.

As a bit of a rabbit hole on the same topic, when i first was doing research on my approach to what i wanted for size of intake and filter i used a calculator that would take your peak power output and redline numbers and calculate a square inch volume of how much filtration you should have. Now i should have read the calculator a little more carefully with its disclaimer that there can be 20% error on either end because by nature of the calculator then a stock porsche 911 with its stock air filter is grossly undersized but improved air filter changes showed that stock was not providing an excessive restriction. Had i read this example and disclaimer i may have had second thoughts on buying a huge 4" flanged K&N that was 6.5" at the base of the cone. By attempting to continue down the path of the 4" intake all i meet was heartache and frustration on nothing ever fitting and by the time i cut things and modified a tonne i had a completely mangled k&n filter that i could not re-use or even think of selling with how much pushing and shoving and cutting i did to try and make it fit.

Some others maybe be able to make this work but my personal recommendation is DON'T. Bob also recommended to me that 3.5" is good for 600hp all day long before it becomes a restriction so given that the best i would ever do with my competition cam and a tune with my solid billet mount and 4130 chromoly halfshafts from xschop; best i think i'll ever see is maybe 385hp and maybe 370 tq? my transaxle should survive just fine with staying NA and not going beyond that especially with the reinforcement plate in.

Anyways, next thing i did was evaluate the fact that i had to deal with putting the MAF immediately after this 3.5" sleeved coupler inside the mouth of the 4" spectre tight 90 because if i put MAF before the filter i would never have enough room to 90 around the headlight popup bar and the necessary 45 kick to get to the angle of the filter that the coolant reservoir dictates. The picture will tell a thousand words here.

Now the nice thing is that with MAF right before steering pump the connector for the MAF is most likely going to reach with factory wiring harness, will be testing that soon as i lay out my harness to see where everything connects before i do a final harness tape wrap to make it look pretty. (figured its easier to do this while i haven't put the harness in the car as long as everything is half proven to reach).

Also another benefit to MAF being here is that since its a solid piece it gives more rigidity to the compounding of couplers and you need some form here to be able to rigidly stay above the power steering belt.

Now after the MAF is where i used a 45 to which i basically cut right after the knee in the 45 because you need as much real estate for an aluminum tubing sleeve that you can then couple a 90 right after this. See the 45 lets you swing wide of the popup headlight bar and tuck right around the corner of the power steering pump reservoir. Note that i can not comment on how different this approach would be for a turn one pump as i believe i just have a stock unit and i am not familiar with the likely dimensional differences between the turn one and the alleged stock unit i have.

Now with regards to the 90, it probably would have been better to use yet again a tight 90 rather than how much i had to butcher (cut, and re-cut and re-cut) this normal radius 90 i had got. This was me just digging in my heels as I really wanted to preserve the red intake to match my guards red exterior for when i pop the hood at car shows when i am all done this build and showing it off (same reason for why i chose to keep my intake exposed and in engine bay and not hidden under the nose panel).

Now after the 90 you need an aluminum tubing sleeve again so you can get back to the take up angle of the filter which has to follow the angle of the coolant reservoir. Now keep in mind you are fighting a few more things here. One being your new coolant radiator hose if you got the double pass rad kit from TPC as well as your steam line routing line. (highly highly recommend getting this by the way if you haven't already)

Now in my endeavours to make the 4 inch intake work i grinded out a significant part of the head light backing but after going to 3.5" it's quite likely you don't need to do any of that. One thing you will definitely need to do is some significant trimming to the top knuckle of the popup headlight bar and then file this super smooth as on my build here it just barely sweeps the back of the 45 and if that was sharp it would probably cut it over time. If you don't grind this down really thin you will definitely have a hit here. have a close look at the 3.5 inch intake with 4 inch filter for comparison compared to the first hood latch trim photos and you will see how trimmed the end of the popup headlight bar is to give more clearance for the 3.5" 45 after the MAF.

Last thing to note is that the hood doesn't totally naturally shut. It needs a bit of momentum on the swing of the hood for it to shut, but it does close and still leaves half a pinky finger of clearance to the power steering pulley and the headlight go up and down with no issues. Gonna build a bracket to support it up for sure from the power steering belt so i can sleep better at night knowing its braced.

I struggled with this a bit but eventually got the win so i can only hope this really helps someone else in what i would say is one of the most creative parts of the conversion and not a textbook "works for all" situation. Although i would almost bet the exhaust will also have its own creative element when i get to that....

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pretty tight but after a support bracket out of aluminum it should be gold. will post back an update on the final build.

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picture attached of the RU-3130 i used and an alternate i was looking at that had slightly bigger size for more filtration and after the fact could have been a tad easier with the 10 degree angle offset which is about the angle i had to massage the last 45 to get it to squeeze just wide of the natural angle of the coolant reservoir.

not sure if the extra width could create more headache in that corner of the fender but truthfully you start to get more towards the end of the cone dimensions for where the back of the headlight starts to swing through for a potential contact point so it could very likely work. Buy it from a place that has a good return policy and keep it in the packing bag while you set it in place to check the dimensional fit if you go with the  RF-1031.

i have not extended this research to any of the other vendor equivalents like air raid or others.

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mine's a 944 turbo transaxle with LSD and oil cooler and pretty sure the stamp is a 5R after getting rid of my old transaxle with bummed 2nd gear synchro and wasn't going to handle the LS1 well with the car being an 88 944S.

my question is that i have the easy pak amsoil MTG 75W90 which is GL-4 readily available to me while redline MT90 is not.....

my readings on other forums like pelican and rennlist show that either works? thoughts? would be ideal to get the MTG if it's not a terrible thing to do for my transaxle while i get closer and closer to fluid fill time....

hopefully someone has some input for me? TIA

Use the Amsoil. It's very good. Redline is good, but overrated in all honesty.

Hotrodz of Dallas wrote:Use the Amsoil. It's very good. Redline is good, but overrated in all honesty.

between the advice on intake size, pics on exhaust build ideas and the recommend on the amsoil for gear oil you've been a massive help. Thanks a ton Bob!

You are very welcome

Hotrodz of Dallas wrote:Use the Amsoil. It's very good. Redline is good, but overrated in all honesty.

I have to agree with Bob.  I'm a lifetime dealer of AMSOIL and have used their products since the late '70s.  Truly quality products.

Regarding the gear oil, AMSOIL SEVERE GEAR lube is the recommended product for an LSD.  You can check it out at this link:
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It's available in 75W-90 and 80W-90 weights.  They also make a product called AMSOIL Slip Lock. for applications that require additional friction modifiers.
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I'll be using regular AMSOIL 75W-90 gear lube in my 5P because it is non-LSD.

Man, thanks for the documentation and posting. I'm about to embark on this project soon and I'm quite daunted by it! It'll be my first project car haha.

i would stay away from any gear oil with friction modifiers for a limited slip diff. friction modifiers have a negative effect on synchro life and function. with a transaxle that runs a common sump with a limited slip a compromise has to be made somewhere, luckily the frictions in our diff dont seem to be prone to chattering without limited slip additives.

i ran both amsoil 75-90 manual transmission and transaxle gear lube and redline mt-90 with great success in my AOR box.

Seem to be irrelevant to the swap to me?

Thinking about just putting two short bolts as plugs to keep debris out. Anyone know different?

Yes I started my swap so long ago and took a life pause that it is indeed one of the old 2 piece bell housings that we are looking at here.

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Gutterboy,

They are for mounting a dust shield.
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I'm presuming you meant the two bolt holes at the bottom....

Gutterboy wrote:Seem to be irrelevant to the swap to me?

Thinking about just putting two short bolts as plugs to keep debris out. Anyone know different?

Yes I started my swap so long ago and took a life pause that it is indeed one of the old 2 piece bell housings that we are looking at here.

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Those 2 lower bolts were used with a stock LS oil pan. The bell housing actually bolted to the oil pan in that location.

guess i should have been more clear, i was meaning the two holes going towards the front of the car that are close together and the top of the bottom half of the bellhousing.

again, seems like they are irrelevant and plan to just plug them.

tackled a majority of my exhaust last night, will try to post pics here but when i go to fill all the fluids i'm curious how much i would need of ford ATF for my hydroboost and turbo style reservoir that does both brakes and clutch.

i cleaned out the reservoir really good and plan to flush new fluid through all the brakes to push out whatever remnant of the oil fluid is in the lines from when the car last ran under its original 2.5L.

so between filling the power steering reservoir, the porsche master cylinder reservoir, the amount to bleed the clutch, and to flush new fluid through the brakes..... curious how much i need to flush and bleed everything from bone dry?

Also for coolant i'm thinking i probably need 2 gallons of concentrate that i would then mix down at right concentration to fill my dual pass rad from kent from bone dry and fill the coolant reservoir?

thoughts on both recommended amount of fliuids?

Gutterboy wrote:guess i should have been more clear, i was meaning the two holes going towards the front of the car that are close together and the top of the bottom half of the bellhousing.

again, seems like they are irrelevant and plan to just plug them.

Got me   .... went and looked and mine is the same.  Might turn out to be good support clamp locations for an O2 sensor wire.  

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that might be exactly what i use those two holes for to handle the additional length i have coming from my 02 connectors. The 02's themselves also have another 18" of length to deal with so something to pin these back with would be great and i still have lots of my aluminum flat bar left. Still have to make temporarly blanking plates for my a/c lines to keep those clean and blocked off till the time comes when this can be driven to an a/c shop and braze new custom lines with the old porsche fittings. will be hunting your thread on the routing of that when the time comes to bring the AC guy up to speed.

Actually as another side question. Anyone know what the single wire connector coming off the driver headlight harness from the firewall is for? My limited research shows that it's probably the 12V power to fire up the electric clutch on the compressor..... If so then it's one extra wire that i haven't run over to the passenger side where the LS compressor is.... Not a big deal but another to do item.

not critical for my imminent first start but still, another thing on the list probably. i'll edit here and post a pic of the connector i am talking about.

so the big headlight harness that goes from the firewall to the front of the car on the driver's side has a red with green wire splitting out of it but also has a black wire crimped into the same connector.

I tracked this down with the schematic in the porsche manual but i have to say it seems rather confusing of a way to wire up the TPC ac kit. i know i need to extend this wire to get it from the driver's side to the passengers side like i have done with extending the other wires with what i believe is the pressure switch on the old AC dryer; but where i am confused is whether i should try to complete the circuit for the hot to the compressor with this same black wire commoned to that hot.

in theory it seems like all i should need is just the black wire which seems to come from the first pic below which i perceive as the high/low pressure switch off the drawer going into the harness and then coming back out of the harness that is parallel'ed with this red/green wire.

The red/green wire seems to be useless since the reference to G50 takes it back to the t22 (if i remember correctly) connector which is going back to the DME. Obviously with removal of DME that wire seems useless and can be ignored? that's my big question. can i cut the connector off from the harness and just run new to the passenger's side?

or maybe its much much simpler than that as i have already extended the wires that the high/low pressure switch used to hook up to in the driver's side cubby over to the passengers for where the pressure switch will be relocated for the new dryer on the passenger's side. So since i already have the BK/RE and BK wires run over to  passenger side to hook up pressure switch maybe all i really need to do is abandon my extra BK wire that i actually have brought back to the harness on the drivers side and just run a brand NEW BK wire from pressure switch to the compressor to complete the circuit?

i'm thinking i have answered my own question here but not totally sure????

also just for confirmation is the third picture with the wiring the high/low pressure switch?

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The wire connector you have circled goes to the compressor clutch. We splice a new wire to that and extend to the new compressor. The line with the pressure switch gets moved to the new drier, which we mount on the passenger side and extend the wires to it.

Indeed that's what i thought i had to do at first, but the fact that both the green and red/green wire are crimped under the factory porsche single connector seemed odd. And when looking at the schematic the red/green appears to go back to the DME which in an LS conversion obviously wouldn't matter so that brings me back to that i probably only need the black.

but then again as per the schematic it seems like the black is a common switched hot wire from teh AC relay to which is parallels to the high/low pressure switch that goes to the new dryer i have already put on the passenger side.

Basically from a schematic view it seems like i don't have to because the same switched black hot wire exits the same harness both at the high/low pressure switch and then again for the air compressor or compressor clutch. Since i have pulled the black wire for the pressure switch that connects to the new dryer already, i'm thinking if my interpretation of the schematic is right then i can just parallel off that to heat up the compressor clutch since its the same black wire. And really the red with green wire should be a delete/ignore.

i guess i can just give it a go and bump the A/C button as a test when i am playing with a bunch of other things on the first few times of firing up the engine; even though i won't have the re-made lines from the firewall to the compressor made up for some time. Then i can report back on whether my understanding of the schematic turned out correct. Seems to be a simple shortcut?

if it doesn't work i know exactly what i need to do lol.

can't solve this one with the porsche 944 shop manuals with the schematics.

have a look at the picture with the blue arrows for the cable that comes from the firewall bundled with a vacuum line correction: not a vacuum line, actually a wire that goes to the passenger side mounted ABS connector.

i did not document my demo 13 years ago and i have no clue what this is for and more importantly whether it should go to the negative terminal or the positive terminal on the battery.

or maybe neither and should go to the grounding point in the battery compartment but would effectively be the same as the negative on the battery but if needing to be grounded obviously that's more preferred to go to body ground than battery.

any direction would be great help as this is not something you guess on for obvious reasons.

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Gutterboy,

I saw your post and tracked down some old pics of when I pulled my battery.
Hopefully they will help.

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Everything but the kitchen sink connects to the Positive Battery Terminal...the exception is the Body Ground Strap coming off the Negative Battery Cable coming from the engine.

I replaced my positive battery cable so I had to go with a different terminal connector.