Newb Build in Asheville NC area LS1 5.7 into 944 S2

I am currently in the process to do the swap and rebuild for the car PICS attached of current state.

I Have the parts below and plan to follow Raymond's Build posts. He is very detailed which is great but Im having a hard time digesting the information. I am not a LS expert thus there are many things I do not understand.

I think the best way for me to go forward is to start a thread for my build specifically. I am hoping I can get input when I get to points I do not fully understand.

Background - I have built a few kit cars and a few ecotech 4 cylinder engines, so I understand some basic things.

Parts I have and plan to use which I have been able to piece together from people on FB selling pieces of Swap Parts.
2001 Corvette LS1 40k miles and ECU - ECU is sent to LT1Swap to reprogram to DBC "Drive by Cable".

TPC Parts:
Motor Mounts - Missing Plates which is on order with TPC
OIL Pan with Pickup Tube
Bell Housing single type
Pilot Bearing and Adapter
Adapter Plate
Throw out Bearing
VSS Kit
Clutch Disk
Hydroboost kit
AC Kit
Throttle Cable
Master Cylinder < ---- Im not sure if this is the Clutch or Brake
Spacers for frame

Other Engine Accessories Parts
Stock LS1 NO MODIFICATIONS to the ENIGNE
Stock Intake and Fuel Rail with Stock injectors.
CTS-V Mounts for Power steering Pump and Alt
CTS-V PS Pump and ALT
CTS-V Belt
187 Thermostat
Idler --- Still having issue with this item and I have multiple ordered to find the right one.
Stage 2 Pressure Plate. --- Ordered based on Advise from Kent at TPC
Stock Flywheel
Stand Alone Harness for DBC
92mm 4 bolt TB and adapter for 3 bolt intake to 4 bolt TB

Transaxle
Stock S2 trans <---- Not planning a 5th gear conversion I live in the mountains and do not plan to be on highways very much.
I have the Transaxle Reinforcement plate but I was not planning to use it am I crazy?

Fuel System is still up in the air for me. From my understanding that is pretty straight forward PLEASE Correct the if Im wrong.

I have the CAR Almost Completely striped for a restoration so hopefully access is a bit easier.

I guess I am not really ready for my first round of questions to the experts but I KNOW I WILL HAVE THEM SOON. Please any help is greatly appreciated love to have anyone follow this thread to help.

If I need to move this Thread somewhere else please let me know and possibly HOW...
 
BEFORE CLEANING PICS
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A BIT CLEANER
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ENGINE BEFORE ACCESSORIES
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ENGINE CURRENTLY
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If you have built kit cars in the past, you will be fine doing this swap. Its basically plug and play. Pretty straightforward, if you are not fabing your own parts and using the swap kit. Imo, the hardest parts of the swap are making a wiring harness, modding hydroboost, and modding/fabricating a dbw gas pedal. Seems none of those apply to you, so it should be a breeze.

Leva wrote:If you have built kit cars in the past, you will be fine doing this swap. Its basically plug and play. Pretty straightforward, if you are not fabing your own parts and using the swap kit. Imo, the hardest parts of the swap are making a wiring harness, modding hydroboost, and modding/fabricating a dbw gas pedal. Seems none of those apply to you, so it should be a breeze.

Thanks!!! I still think I have questions. Such as do I need the Adapter Plate for the BH? Do I need the mystery adapter plate spacer? What's the easiest way to do the Fuel system? C5 Filter/Damper under hood or in back?

Do you know what this Master Cylinder is for? I guess the clutch but not sure why I would need it. Or should I use it anyway

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viperbmw69 wrote:

Leva wrote:If you have built kit cars in the past, you will be fine doing this swap. Its basically plug and play. Pretty straightforward, if you are not fabing your own parts and using the swap kit. Imo, the hardest parts of the swap are making a wiring harness, modding hydroboost, and modding/fabricating a dbw gas pedal. Seems none of those apply to you, so it should be a breeze.

Thanks!!! I still think I have questions. Such as do I need the Adapter Plate for the BH? Do I need the mystery adapter plate spacer? What's the easiest way to do the Fuel system? C5 Filter/Damper under hood or in back?

Do you know what this Master Cylinder is for? I guess the clutch but not sure why I would need it. Or should I use it anyway

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Welcome to you forum and to your new project. You should be able to build the car with out many issues.

The spacer you are asking about, I assume is the 1/4" thick spacer that goes between the bh and engine block. If so, then yes it is required. Otherwise the clutch pressure plate will hit the bh.

The master cylinder is for your clutch and will have to be used. The stock master cylinder doesn't have enough volume to operate the clutch correctly.

Use the C5 filter at the back in place of the factory Porsche filter. If you bought Kents fuel filter kit, then it has all the correct fittings to adapt it to the existing fuel lines.

Hotrodz of Dallas wrote:

viperbmw69 wrote:

Leva wrote:If you have built kit cars in the past, you will be fine doing this swap. Its basically plug and play. Pretty straightforward, if you are not fabing your own parts and using the swap kit. Imo, the hardest parts of the swap are making a wiring harness, modding hydroboost, and modding/fabricating a dbw gas pedal. Seems none of those apply to you, so it should be a breeze.

Thanks!!! I still think I have questions. Such as do I need the Adapter Plate for the BH? Do I need the mystery adapter plate spacer? What's the easiest way to do the Fuel system? C5 Filter/Damper under hood or in back?

Do you know what this Master Cylinder is for? I guess the clutch but not sure why I would need it. Or should I use it anyway

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Welcome to you forum and to your new project. You should be able to build the car with out many issues.

The spacer you are asking about, I assume is the 1/4" thick spacer that goes between the bh and engine block. If so, then yes it is required. Otherwise the clutch pressure plate will hit the bh.

The master cylinder is for your clutch and will have to be used. The stock master cylinder doesn't have enough volume to operate the clutch correctly.

Use the C5 filter at the back in place of the factory Porsche filter. If you bought Kents fuel filter kit, then it has all the correct fittings to adapt it to the existing fuel lines.

Ok thank you I really appreciate it.

You are very welcome.

viperbmw69,

It's great that you put your project on the Forum.  I just saw your thread today and it sure reminds me of my project adventure!!

You are going to find there is no shortage of very experienced individuals on the Forum that have done this swap numerous times, and most importantly are willing to help people like us that are new to the game.

As a few of the folks have indicated, your project CAN BE straight forward if you stick with the basic swap. Most every regular scenario has been explored and improved over the years.

I'm glad my thread can help you, that's exactly why I take the time to produce it.  I have received so much excellent advise from the Forum experts and it seems only right to capture and share it.

Keep the updates coming and don't hesitate to ask questions!

Nice guards red machine.

i have same color on my 88 944S and getting close to first start on mine.

my only warning is with regards to your 92mm TB. that's massive and even with my stock TB size (78mm) she's still tight with the hood. Not saying its impossible but i had quite a fight with getting stock TB and intake designed so hood would close and i would think its even more of a challenge when you get to that final stage of the build with that larger TB.

But that said RaymondP's amazing and detailed and pic intensive thread has an LS2 with a significantly large TB.

In hindsight, with Bob's advice and how much razor thin space there was on my intake to the corner and around the popup headlights i think Bob's preferred option with the 120 degree vibrant pipe into the nose panel for the air filter is a great way to alleviate headache. Made a full documentation on intake on my newb thread.

hoping to document my exhaust build here soon for that part.

one thing i will say is that a good vertical zip disc grinder and some aluminum/mild steel flat bar and a vice will be a great friend of yours for fab'ing brackets and mounting them with a rivnut tool for things like mounting the heater valve and say a coil relocation bracket you can get from summit racing for your hydroboost on the driver's side rather than the involved bracket raymond went with (neither solution is wrong, but i found the relocation brackets with rivnuts was less work and still cheap).

Adding the transaxle reinforcement plate starts with Kent's first question to me when I had originally decided not to and then revisited the topic just before this last Christmas.

"how much power you making? (which/what engine and what else for power adds)

I have a '97 5.7L in the car that by surprise also has a competition cam put in it from previous Rx7 swap it came from so I'll be somewhere north of stock 350hp maybe even 380hp.

My next biggest mistake was assuming I had shored up any issues by getting 4130 chromoly half shafts from Rob (@xschop) and his polyurethane bushing on billet mount to stiffen that up.

No problem with that part but what I did was eliminate any give or slop the transaxle would need for all the torque from the new ls1 power. This puts all of it on that final ring gear just waiting to twist and grenade my precious 5R transaxle with LSD. and I definitely have no one who can rebuild something like that transaxle where I live.

I'd say if your doing anymore power than a stock 5.3 or have a transaxle that is from a turbo LSD or not, it's cheap enough to be more safe than sorry and just put it in. Not a crazy big job and both my thread and Raymond's thread have extra detail beyond the existing write up from Kent to put the plate in. Just track down a machine shop to shave your end cap down a quarter inch and the rest is quite easy. Make sure you have an air or corded impact, cordless will NOT get the nut off under the endcap.

I had my 8 year old daughter help me with sliding the gear over top while I held the synchro spring in place under the tabs. So with a mild assist it's actually quite easy. Shouldn't hold back from doing this while you have the transaxle out.

Since I learn by doing it wrong the first two times at least I had put my 5R transaxle in and then after discussing my error above with Kent took it back out over Christmas got the endcap shaved down, put it all back together and back in and reconnected my fuel kit from Kent thanks to the quick connects and had it all back in second week of January.

Lastly If your thinking of tracking the car at all I'd say the plates a must for preserving transaxle, but same could be said for hard spirited driving I think.

You have come to the right place for guidance on your LS swap. There are many knowledgeable people here to help you. I purchased the Renegade Hybrids shorty headers for my car and they fit well. They were pricey for the ceramic coated units but the extra cost was worth it. I would highly recommend ceramic coating on your headers because it is pretty tight under the hood and you need to keep the heat off of all the hoses and wiring. I made heat shields for the starter wiring, power steering and oil cooler hoses to be safe. I would question if the large throttle body will fit under the hood. The stock throttle body with an F Body intake manifold just barely fits. It is possible to retain the pop up headlights and the stock hood latch. I was able to do it with my car. Good luck with your project. Gil[You must be registered and logged in to see this image.]

I'm just a couple of hours away if you want to look over mine and maybe pick up a set if headers.

Sorry for the Delays in posts. I have made quite a bit of progress so far.

Engine Build Complete.
Engine Installed.

I have a few questions about issues

1. I am using the Stock Radiator since I am in no way building a power house. This is build is for a fun weekend car.
I need to better understand how to plumb the Radiator Hoses.... I know the inlet and outlet ports on the RAD. Where does the overflow tank outlet connect to the Radiator? The small port above the Stock Hot inlet I believe is for the Steam Lines?

Also the Power cables.

Silly Question... How do I connect the Battery Power wires?
I think I need to go
1. Battery + to Alternator
and
Battery + to Starter Power side.
Or do I need to go
2. Battery + to Starter and Starter on same post to Alternator

Also Grounds I assume are

Battery - to Motor "Somwhere"
and

Battery - to Starter -

Also the Starter relay I "Think" I understand

Red and Black Porsche wire connect to Purple Wire out if my Ebay Wiring Harness.
Then cut the Purple wire plug off the other end and connect it to the Starter trigger wire.

What's the best way?
????


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ls1 wiring harness manual

you can use this guide to figure out your factory porsche alternator battery cables but basically what i did is i split them so i could get the starter jumper wire to tuck in between cross member and front of oil pan (towards front bumper) and then sneak up and pick up the terminal on the alternator.

then off of second power post you connect that one to your battery.

my red with black wire was quite long enough that it reach on its own to pick up the starter solenoid.

tested mine just over a week ago when i first lit up the dash for first time in 14 years and did a teaser crank so solenoid definitely engages and since i bothered to check the 470ohm resistor on pin 15 of C2 red connector and mine was basically toast with lead ends broken off. Soldered a new one in line with that pin to try to prevent from overcharging and killing the diodes on the alternator. This pin 15 eventually turns into the harness plug that plugs into the top of the alternator which is different than your charging jumper that uses the power post on the starter to get back to the battery. I found doing it this way let me completely reuse my porsche power cables which are still in great condition cause my car has spent much of its life in the garage rather than running but hopefully that is changing real soon.

and with regards to the radiator, i was going to go down that path but then went the easier road with just getting the rad kit from kent cause you get all the right hoses and everything just perfectly matches up with the ls connections including the porsche reservoir. if your not pushing it hard you can still save a bit by not going dual pass but honestly there is so much headache that disappears if you go with his radiator. my bad was not keeping the 944 fans as well as the fan switch since i turfed that rad.

many people just leave the plug in the rad and forget about the porsche fan switch and let the ecu control pulling in the fans from the chevy ecu fuse/relay block.

Gutterboy wrote:ls1 wiring harness manual

you can use this guide to figure out your factory porsche alternator battery cables but basically what i did is i split them so i could get the starter jumper wire to tuck in between cross member and front of oil pan (towards front bumper) and then sneak up and pick up the terminal on the alternator.

then off of second power post you connect that one to your battery.

my red with black wire was quite long enough that it reach on its own to pick up the starter solenoid.

tested mine just over a week ago when i first lit up the dash for first time in 14 years and did a teaser crank so solenoid definitely engages and since i bothered to check the 470ohm resistor on pin 15 of C2 red connector and mine was basically toast with lead ends broken off. Soldered a new one in line with that pin to try to prevent from overcharging and killing the diodes on the alternator. This pin 15 eventually turns into the harness plug that plugs into the top of the alternator which is different than your charging jumper that uses the power post on the starter to get back to the battery. I found doing it this way let me completely reuse my porsche power cables which are still in great condition cause my car has spent much of its life in the garage rather than running but hopefully that is changing real soon.

and with regards to the radiator, i was going to go down that path but then went the easier road with just getting the rad kit from kent cause you get all the right hoses and everything just perfectly matches up with the ls connections including the porsche reservoir. if your not pushing it hard you can still save a bit by not going dual pass but honestly there is so much headache that disappears if you go with his radiator. my bad was not keeping the 944 fans as well as the fan switch since i turfed that rad.

many people just leave the plug in the rad and forget about the porsche fan switch and let the ecu control pulling in the fans from the chevy ecu fuse/relay block.

I don't really understand... What do I need to connect the FANs? I was assuming since my RAD and FANs are Stock I just plug them in as stock and the porsche wiring will run the fans if needed based on Temp Sensor? Is this wrong?
As for the Power Cables I think I understand that part better now.

If you are running stock rad and fans, then your fans will work just fine. If at some point you find the stock rad doesn't cool it good enough, then going to TPC's rad kit will allow you to retain the stock fans and wiring while cooling much better.

Gutterboy is on point about the battery cables and cooling system except I would not bother with the cooling kit from TPC.  I purchased the dual pass radiator and cooling kit from Kent and I ended up removing the fans from the kit and reinstalling the stock fans from Bob's recommendation.  The stock Porsche fans work much better.  I was only able to use one of the hoses from the cooling kit on my car.  I also had to purchase a different outlet from Summit Racing to clear the belt and pulleys.  I could not use the lower hose from the kit.  You asked how to connect the overflow tank to the cooling system on your previous post.  I spliced a tee into my upper radiator hose and ran a hose to the overflow tank.  I ran the small cooling hose below the throttle body on the engine to a tee that split to the overflow tank and the radiator.  I also reused my positive and negative battery cables.  I believe I shortened the positive cable and soldered a new terminal on it because the starter is on the other side of the engine with the LS.  I ran a 6 gage wire from the starter terminal to the alternator for the primary charging wire.    [You must be registered and logged in to see this image.]

Kent has modified his shroud to accept stock fans now. So, that issue has been solved.

Good to know about the revised fan shroud. I mounted the stock Porsche fans using aluminum flat stock to eliminate the clearance issues with the pulleys. I posted a picture a while back. Things have come a long way to make these conversions easier in the past 10 years.

yes the improvements have been astounding, from my original purchase of my conversion package from eric i think i added another half of it with various updates.

i got the radiator kit from kent quite recently and everything worked handsomely after i had my 944 connection from quebec get me some fans again after i threw my original ones away whoops.

all the hoses he gave me and the brass tee for my overflow and steam connection worked absolutely great. for the bottom lower left hose i had to use some silicon grease to get that one to pop on a little easier before final clamp. Only extra thing i needed was some vibration rubbers for mounting the radiator, rather than a pay a fortune to the guy on ebay, our version of harbour freight called princess auto had some extremely similar ones that i cut to proper height and they had a metal threaded stud that i could use a nut to fasten to the top for the stoppers to secure the new rad. Worked really well.

i did have to make some minor notch shaving of my porsche fan shroud to make it not hit the front of the LS but this was actually quite minor. As are many things when you have a 3" vertical grinder to get things a bit more modified to fit.

Ok I need some help!!!!....

I am having a no start problem. I have had the LS started before and I know it should run.

Things I have checked so far.

1. Pink ECU wire is getting 11.5 during cranking 12.6 normally brand new battery as well
2. Fuel Pump is feeding fuel to pressure.
3. Removed and cleaned and replaced o rings on the Injectors. Also used tester to verify they are all working correctly.
4. O2 Sensors are plugged in and getting hot on key turn.
5. I have ZERO codes on the ECU when I use my scanner.
6. During Crank the OBD2 port and scanner showing 140-150RPM for cranking.

Does the anti theft have anything to do with LS swaps? I started it before I reinstalled all those pieces and now I tried to remove the Anti theft and still no start.

It seems like its not firing. What's the best way to verify firing on the LS? Its tight and I would like to be able to verify without removing anything but I can I guess.

If you are using the stock GM engine computer, it will have to have the theft deterrent turned off with a tuning program such as HP Tuners. There are people on line that can do it for you if you send them your ECM. Maybe you know someone local with a tuning program that can do it for you. You can check spark with a spark tester or a good spark plug connected to one of the plug wires and a good ground. Good luck, Gil

gwistrup wrote:If you are using the stock GM engine computer, it will have to have the theft deterrent turned off with a tuning program such as HP Tuners.  There are people on line that can do it for you if you send them your ECM.  Maybe you know someone local with a tuning program that can do it for you.  You can check spark with a spark tester or a good spark plug connected to one of the plug wires and a good ground. Good luck, Gil

Thanks, I actually already had the ECU programmed by lt1tech.com so not sure why this might be in the ECU issue

Since the theft deterrent has been removed, you will have to get back to the basics. Fuel, spark, and compression. You can use a noid light or a test light to check for injector pulse and a spark tester or a good spark plug grounded to the engine to see if you have spark. Since you have an RPM signal, your cam and crank sensors should be OK. You can look at other engine data with your scan tool to see if you have proper information from the sensors. A good key off engine on test is to look at all of your temperature sensors (coolant, intake air, and manifold air temperature) to see if they all read room temperature. Does your MAF signal change when you start to crank the engine? If you pull one spark plug, what does it look like? Is it wet or dry? Another often overlooked item is to make sure you have good engine grounds. I believe there is at least one specific wire from the ECM harness that needs to be grounded on the engine. The engine needs to be grounded to the battery and the body too. I hope this might help, Gil

Like Gil said, check grounds and spark. Sounds like you have good fuel pressure and injectors are pulsing, so your crank sensor is good.

If you have no spark, a quick way to test the ignition relay, is to swap it with the fuel pump relay. If you now have spark, you found your culprit.

I have also had bent pins on the pcm cause no starts. Sounds like you already had it started at one point, so prob not the cause.

I need help understanding the fan wiring. I have searched and Searched and I just don't understand, Can someone Dumb it down like to a Child or Dog

I have the 3 relay setup in the picture attached. I am going to wire the system EXACTLY like the diagram, Which means the Fans are NOT in sequence... (I think) I don't quite understand this setup I did see the explanation from

944-LT1 wrote:The computer controls the ground path for the three cooling fan relays. The relays are used to control the high current flow to power the cooling fan motors. Both fans operate together. When minimum cooling is required, the PCM energizes cooling fan relay #1 and both fans operate at low speed, since the fans are connected in series through cooling fan relay #3. Cooling fan relay #2 is open (not energized) and is not used for low speed operation of the fans. When maximum cooling is required, the PCM energizes all three cooling fan relays. The left fan is still powered through cooling fan relay #1, but is now grounded through cooling fan relay #3. The right fan is now powered directly through cooling fan relay #2 and both fans operated at high speed.

but I do not understand. I would love to have the fans function like they do stock so both run at low speed and both run at high speed,,,,, This is not how I read the diagram I read it as Low fan is one Fan and High Fan is Two Fans..... Am I wrong?

AC
Also where and how do I wire in to make the Fan run on low speed when AC is on???? What's the best way? I have the AC Compressor installed and Wired to the OEM AC trigger wire. Do I need to also wire in another connection on this exact same wire?


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