2001 Porsche 996 LS1 Conversion Thread by 1dirtyZ

14 minute(s) of a 536 minute read

dropped the car off at a buddy's shop to have him tune the idle surge, calls me up after a few hours telling me it made 378 to the wheels !! and that it idled quite nicly and pulled real smoth and hard .

he then proceeded to tell me that it was not what he expected from a 6.2 and l98 heads ,,,, to which i replied that is was the "***** 5.7" that i built ages ago with 5.3 heads that were somewhat ported ( read porthed a few ports , got bored, decided that those would do ) . needless to say he was surprised 

he just has to do one more thing with the cold idle , and then he will add some more timing cause he thought this was the other motor and only put in 22 deg of advance .

sooooo if you figure that it made 378 at the wheels , at the flywheel @ 15% loss that would come out to be just under 435 , which is higher than the output of the original porsche engine of 420 . but that is not my target , i want 420 to the wheels!!!! 

anyhow i'm waiting for the guys to send me a video of the runs so i can post it here .

07.07.12

well i guess i have a few milestones to celebrate 

after dynoing the thing ( will post the vid soon ) i took the car over to have the AC done. i dropped the car off at a well known shop and told them "fix it " the guys did a great job, and the owner recomended a different style compressor than the one i got , so i went with it and he did the necessary fabrication to the compressor mount as well as cleaning the whole system before installing the new lines. 

well after that i took the car over to the upholsterer for covering up the rear shelf area and fixing the airbag cover, which they did quite well!

i already put a few fun miles on the car for "testing " reasons 

and just been finishing a few little things here and there since i'm a bit motivated now , i already jacked the rear up and went under the car to see where a small water leak was coming from , turned out to be a loose clamp on the heater hose. also insulated the ac lines coming out of the compressor because of their close proximity to the headers and muffler.

there are a few issues i have to take care of now , first off the rear cover release isn't working , i remeber fixing it with the old harness but i'm not sure what i did so i guess i have more wire tracing to do 

also noticed that the AC belt is off one tooth , so i have to realign the ac bracket to get it in line. 

another thing i have to do now - which is quite new for me since i never worried about the AC system in anyof the conversions i have done before - is wire the ac signal to the pcm to bump the idle when on and turn the fans on too.

and a bit of bad news to report , i think all the "testing" is taking its toll on the clutch: i think i smelt some roasted clutch today 

anyhow, the list of things to do for now is :

- snap pics 

- trace latch release wires

- wire ac signal and check 

- install rocker panels 

- remove whats left of the old stereo 

- take car over to get new nav/stereo system installed 

- take it to get detailed inside

07.21.12

more updates 

i did snap some pics :

here is how it looks after painting the wing and bumper:

and here is the interior work they done at the upholsterer, airbag cover mounting :

how they mounted the DME and fuse block tot he shelf:

and how the shelf looks installed :

and how it all looks whith the carpet installed :

i also fixed the rear hatch release , turnes out it wasn't getting a positive signal (the release switch up front just grounds the circuit and actuates the release) because the positive signal comes from the spoiler ( retracting and extending ). 

also checked the AC signal wire and spliced into it and connected it to the LS PCM , now when ever the AC kicks in the RPM should bump up and the fans kick in ( i say should cause i still need to to adjust the AC on idle parameter )

and i finally got around to installing the rocker panels , which i forgot to take a pic of 

so right now the dwindeling to-do list is as follows :

- ac bracket alignment 

- remove old stereo unit 

- take car to get new stereo unit installed 

- detail inside of car 

- tune ac rpm and more timing

- check why pass low beam not working 

- rear wheel alignment 

- check speed sensor wiring ( i think i have the brake wear and speed sensor wires confused)

07.24.12

well not much to report but i did put some more miles on the thing and thought i'd share my first ( well sorta first) impressios of driving the thing.

first off the car rides smoothly , it soakes up bumps and imperfections nicely which really surprised me. and i really like how it pulls under WOT . 

-the throttle pedal is a bit on the heavy side - no wonder since the cable is about 4 yards long and snakes its way around the car body. this coupled with the small flywheel and huge *** cam i have in there make for some interesting slow launches from a dead stop.

-the thing needs more low end torque just off idle , the 5.7 engine and huge cam ( something like 24x duration and 64x lift ) and low mass flywheel and clutch make moving from a stop a bit difficult , you need to spin the clutch a bit to get it to move without bogging . i guess that the new engine combo shouldn't be as hard to launch as this given the new cam ( cheater cam ) , bigger cubes , and a heavier clutch (dual disk setup).

- car has an issue with ideling with the AC compressor on: as soon as the AC compressor cycles on the engine dies due to the load it places on it , when crusing or on throttle its not an issue just when ideling. i still didn't mess properly with the tune to try to fix this , but i did raise the "ac on" idle speed which didn't help. i'm sure messing with hptuners for a bit will have this issue sorted out.

- the exhaust is a bit on the loud side for what i have in mind - its perfectly ok by muscle car standards - but i would prefer it to be a bit quieter. there is a droning sound , which happenes to be the loudest sound the exhaust is when cruising around 2000 rpm , but i quickly dies down when you pass 2300 rpm. guess thats the price you pay for a free flowing exhaust .

i'm not worried about it right now since the new engine will have lower compression and turbos to muffle the sound even more. 

- i still have to get used to driving such a small car ! 

- steering is on the heavy side , its totaly managable being without power but i'm starting to like the idea of turning the wheel with one finger 

- i also found out the horn only works with the ignition OFF , and as soon as you turn it on you get nothing ?? more wiring to trace i guess 

- i finally washed the car and cleaned the inside a bit ( wiped it with a damp cloth ) and it looks better than before i did find out there are a few dings in the pass side sail panel ( around the rear window) that i need to have removed , but thats on the might-do-some-time-in-the-distant-future-list

07.28.12

i have to say it was a pretty fun weekend 

decided to take the thing to the track, just to get a baseline . i still did not connect the front driveshaft so i was not expecting any great numbers.

i was surprised how well the car hooked ; those are pretty old tires in the back and it was rear wheel only with no LSD in the rear . i guess having the weight of the transmission and engine sitting on the rear tires helps 

i also found out that the rev limiter was set at 6000 rpm !! so i ended up using that as my shift light 

regardless , the car did a not so great sixty foot time of 2.05 , and et of [email protected] mph i think i can squeeze a 12 second time slip with just changing the rev limiter 

but its still a bit away from my target of beating the time this car supposedly did with its original engine ( see the time slip i found in the car when i first got it in the first couple of pages of this thread). funny thing is i don't know which time on the slip was for this car - it could either be a 12.98 et or 12.07 et 

anyhow , next weekend the new cd/nav system should be installed , front driveshaft too , and most likely a new tune just to make sure 

so far i have the the SRT8 grand cherokee wanting to race me again , as well as a highly modified race evo. i'll try and stirr the local pot and see what other races i can line up 

i might just hit the local fourms and start being an *** and see if i get any nibblers

08.01.12

not much to report other than that i have installed a JVC head unit, which looks kick *** and i had them do a quick clean and polish of the interior while it was there. ( sorry no pics yet )

i also reinstalled the front driveshaft in preperation for the weekend races .

oddly the car decided to develope a sudden "rpm Rise " , up to 3000 rpm when ideling . it just happened when i was parking the car and it almost felt like a sudden vaccume leak ; so i poped the engine lid and started to look for leaks , but nothing was evident. so i decided to check the vaccume hose on the back of the intake manifold ( booster hose) to see if it split open or had a cut or came loose, and given that i can't reach it easily i had to remove the intake manifold ( a simple 3 hour job!! ) and when i did remove it i found out nothing wrong with it 

so i rerouted the booster line to the front of the intake manifold for my sanity and ease of service later on and reinstalled the intake . i then decided i should check the iac sensor , so i swapped it with the one i had on my camaro , which made no difference ..... so i just sat there and scratched my head for a few hours 

then i thought , why not just lower the idel screw!!?? to which i did and the idle dropped down immediatly !!! 

so apparently the IAC i had in there was stuck in the closed position before , and decided to pop open when i was parking , which would also explain why the car would not respond to changes in idle rpm i made in the tune as well as dying when the ac was turned on at idle.

so to make sure i let it idle and turned the AC on and it bumped the idle as it was supposed to do and did not die 

which means i am now even happier than before !!!

so the lesson of the day is " try the easiest , cheapest fixes first " .

on a side note , it appears this swap is getting popular 

08.03.12

quick update , took it to the track for more "testing" 

i had the front driveshaft in, so it was time for clutch dumps 

i did a few runs trying to get a feel for the car , but i'll cut to the good stuff : i took it up to 4000 rpm and dumped it , which resulted in a 1.93 sixty foot and a 12.7 @108.5 

so, am i happy ,,,, kinda i broke the old number i found on the time slip i found in the car when i first got it , but there was a 12.8 and a 12.2 (IRRC) on that slip , so the goal of braking that number is half done 

so am i done testing??? hell no , it still have 3000 rpm more to go 

the clutch didn't show any signs of slippage , so i guess next time out it will be 5k dumps and more 

i also noticed when logging the runs that my timing never went above 24 , so i guess i have to do something about it i'm thinking that 27ish timing should be ok. 

another thing to add , the IAC motor decided to take a crap on me and come appart ,, 

i'll post some vids as soon as i get them .

08.15.12

not much to report , but here is a pic of the interior after the headunit install, the interior still needs to be cleaned and polished:

moving along , i got a stock GTO pan and started getting it ready ; i cut the back part out so it would clear the factory rear sway bar:

i'm thinking of going with the gto pan to make things a bit cleaner under the car. right now there is some weeping going on from the perimiter of the pan and from the fittings going to the oil filter. plus running the GTO pan will place the filter on the pan towards the rear of the car , wich will free up some space for the turbos previously taken by the cooler lines. plus the GTO pan is alot more rigid than the sheetmetal one i have now and has the sump placed in the right place for acceleration g forces. and if you are wondering if it hangs too low , it doesn't : the GTO pan still hangs higher than the stock porsche stuff. here is a pic of the exhaust manifold i plan on using showing how low the turbos will hang 

i'm not planning on doing much work on the car right now , i might just take the front wheels off to see why the brake pad light is on in the dash . i 'm also thinking of hijacking the check engine light on the dash and wiring it to the LS1 PCM. i'm also waiting for a repair kit to fix the "rising sun" spot on the AC control screen and as soon as that shows up i'm fixing it. and if i have time i might just drop it off at the detailers to get the interior all prettied up