Techno Duck's LS1 conversion

Dropped off a Spec Stage 1 disc and an extra pilot bearing just incase earlier today. I am really hoping their is an obvious smoking gun when its torn down again.. like a scorched pilot bearing or clutch disc that looks like a potato chip..  .

I was talking with a friend at an auto-x yesterday and he reminded me that Lime Rock is really strict on noise limits, the current being 86db. I think the 951 with its current exhaust would blow that number out of the water... so its probably better i bring my other car   .

Problem solved! After tearing down the clutch assembly again, found the pilot bearing adapter was starting to work out of the crank! Thom said it could be taken fully out by hand. As a result it was riding up against the hub on the disc causing the shifting problems.

Here you can see where the adapter was rubbing up against the disc's hub. The adapter was reinstalled using Loctite retaining compound this time around. For good measure we replaced the disc with another stage 2.

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The engagement of the torque tube into the pilot bearing was checked while it was apart also..

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Ive put about 30 miles on it so far and its driving great. The car is 10x more enjoyable now that i can actually shift it into gear without having to force it in.

I swapped a new .75" bore clutch master in to replace the larger .813" bore i had. Everything feels great now... the .75" bore is definitely the way to go with these particular master cylinders ive been trying.

I also took care of some wiring odds and ends. I grounded the oil level switch light so the light stays off now. Also got around to hooking up a dedicated CEL light. I used a 12v panel mount LED available at any Radio Shack and cut a piece of aluminum out to fit in one of the blank gauge holes.

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Early next week ill be having the windshield replaced finally. Then late next week ill be dropping it off at the other shop to have some work completed. Finally going to have all of the oil lines remade. I am also going to have them mount a different set of fans from Spal. I ordered these dual 11" fans with a integrated shroud. I took some rough measurements and some trimming of the shroud will be required. But i think they should work with a few modifications.

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I dont think the single 16" fan is up to the task. I think a shroud would probably make it adequte, but i figure for the work involved with fabricating one it will be easier to go with the dual fans instead. They have the benefit of flowing another 700cfm or so. Also the single fan draws quite a few amps at start, the spec sheet rates it at about 20amps, but i suspect it is closer to 30amps on start up. The dual 11" fans are rated at 12amps each. What i was thinking of doing is using the two fan control outputs from the PCM to control each one individually. I think i could probably set them to come on within 1 degree of each other so they dont both kick on at the same time.

I wired up the "!" in the stock instrument cluster as my CE light.

I also have dual 11" fans, but in my car they had to be mounted staggered, not side by side like that pic you have shows. Wouldn't clear the pulleys on my car that way...

So glad you got your clutch sorted. Enjoy! Do you want to sell that 13/16" master? Is it the Wilwood compact type? Did you modify it at all to fit?

Rich

Rich, it is the compact remote type. It has however been heavily modified to fit the mounting bracket i am using though.

Strange that that the pilot bearing adapter moved out. The one time I had to pull mine, it was worse than pulling teeth, I can't imagine it moving on it's own.

Spal fans arrived today, i did a quick mockup and it will be a tight squeeze. Comparing to the stock fans, the fan size is actually fairly close, both around 11"s. The stock fans are also slightly shallower in mounting depth at just under 4", the Spal fans are around 4.5". Note this mounting depth takes into accounts how the shroud stands up off the radiator core. Mounting depth is not a concern really, plenty of space on our cars.

I laid out the measurements for the Renegade Hybrids radiator on my bench;

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The Spal fans basically take up the entire size of the RH radiator! The areas with blue tape are roughly where the hoses connect and would need to be cut out. So a portion of the top left and bottom right corners on the shroud would need to be cut out to accommodate the inlet and outlet.

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Now here is the same with the stock fans. The stock fans are about an 1-1.5" shorter than the radiators core. Not a huge deal. Width is perfect for the width of the core. The gap left across the core height wise can be made up by just welding a flat piece of aluminum across the width of the radiator; doubling as the mounting point. No modifications needed to the fan shroud at all.

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Now here is the space you have to work with. The only area to really work around is the water pump pulley which sticks out. I measured proximately 1.8" from the core of the radiator to the tip of the waterpump. The stock fans are slightly more shallow in the center. Also because the stock fans are shorter than the radiator core, the position can be moved up or down to work around the waterpump pulley if need be.

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With the Spal fans, the shroud sticks out roughly 1.5" where the pulley is. So it should fit fine. The ribs on the shroud that would sit on the radiator core could be cut down some to give even more clearance if needed.

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I am going to have to think about which direction to take. I bench tested both the Spal and stock fans and subjectively the Spal fans seem like they blow quite a bit more air. The Spal fans also benefit from being 25+ years newer. The downside though is the shroud will take quite a bit of trimming to fit. The stock fans i think would actually fit much better, and probably much easier to mount.

The other option is to retain the single 16" fan and just build a shroud around it. If i go this route, the fan would have to be spaced off the radiator maybe .5" so it can effectively pull air across the entire core, then a shroud built around the fan.

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The shop wont be able to work on it this time i am home unfortunately, so ive got plenty of time to think about it. It will be late August before we have time to get to this.

I will likely go with one of the dual fan options. This will reduce the instantaneous current draw when the single fan starts vs staggering the start of two smaller fans. Also the dual Spal fan flows roughly 25% more air than the single 16". I bet the stock fans flow more than the single 16" also.

Did some further research on fan options; here is what ive come up with so far.

On paper the fan i am using now moves the most CFM at zero suction (unloaded so to speak). But i realized the more accurate numbers will be to look at the CFM of the fan pulling a vacuum through the core of the radiator (measured with a water column).

The fan i am using is one of the slimmer models with curved blades to reduce noise. Here are some basic specs..

Spal 30102049 Slim Curved Blade (what i currently use)
CFM @ 0 in-H2O = 2024 @ 19.5A
CFM @ .5 in-H2O = 1280 @ 20.3A
CFM @ .7 in-H2O = 608 @ 18A

Spal 30102120 Slim Straight Blade (Same dimensions as the above)
CFM @ 0 in-H2O = 1918 @ 18.5A
CFM @ .5 in-H2O = 1280 @ 20.8A
CFM @ .7 in-H2O = 926 @ 20.2A

Spal 30102082 Curved Blade (Different dimensions than the slim models, about 1" thicker also!)
CFM @ 0 in-H2O = 1918 @ 23.7A
CFM @ .5 in-H2O = 1499 @ 25A
CFM @ .7 in-H2O = 1245 @ 24.7A

Basically what this says is that even though the slim curved blades move more air on paper, under real world conditions its ability to pull air through the core of the radiator is not nearly as great. Its performance really drops off around .6in-H2O, nearly 15% less CFM than the slim straight blade fan, at .7in-H2O nearly 35% less CFM! Now i am not sure exactly what kind of numbers to expect when pulling through the radiator, but the Renegade radiator is roughly 2.75" think which is more than your standard automotive radiator.

Now the Spal 082 fan would likely be the 'end all' fix and provide plenty of cooling at the expense of higher current draw. But it unfortunately will not fit due to the space constraints with the water pump pulley. The overall height of the fan (including motor) is similar, however the shroud is 2.1" thick where as the slim fans are 1.1" thick.

What i think i may try is the slim straight blade model which atleast on paper seems like it will be able to move more air over the core. It also has the benefit of being a direct swap so it will be easy to try. The downside will be a louder fan.. which i probably wont be able to hear over my 4" exhaust anyway .

The next step i think will be to try dual 11" fans, likely the Spal 30102800HO or 30102054. I am going to return the dual shrouded setup as i think trying to get the universal shroud to work is more trouble than its worth. Two 11" Spal 054 fans would likely be the logical choice as they require half the amps nearly as the HO fan and still move about 25% more air than a single 16" fan.

Spal 30102800HO (Pulls serious current! Would require a very heavy duty harness)
CFM @ 0 in-H2O = 1605 @ 24.5A
CFM @ .5 in-H2O = 1384 @ 28A
CFM @ .7 in-H2O = 1289 @ 29A

Spal 30102054 (Same fan used with the shroud)
CFM @ 0 in-H2O = 1375 @ 12.8A
CFM @ .5 in-H2O = 885 @ 14.1A
CFM @ .7 in-H2O = 617 @14.5A

Put nearly 500 miles on since working out the shifting problems and it's running great! The last few days I've been accelerating progressively more aggressive with it now the clutch is mostly broken in. All I can say once it passes 3k rpm at full throttle it screams! Such an awesome performing car all around. A few of my friends said it sounds absolutely mental flying by   . I've got around 1700 miles on the swap so far and could not be more happy.

Did one tank of mixed highway and returned about 20mpg. The last tank was all city and it was just under 15mpg, it's hard to lay off the throttle   

Made it too a cars and coffee on Sunday morning and it was a real crowd pleaser as usual.

I took a quick video while testing a new gopro and external mic setup. Looking forward to getting some better in car now while on the track.

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Jon,
Regarding the fans:
The 082's are the only way to go, as you pointed out. To make room you can pivot the side rad supports forward about 10 degrees. I moved mine years ago to gain a little more space between engine and stock fans and I still have room for the AC condenser. Before that I tried several thinner SPAL fans without much luck. I documented it on the old hybrids site, so now it is lost.
Regarding the sequence of fan operation: Unless you have a dam between the two fans, one that seals the areas between each fan all the way to the face of the core, operating one fan will simply pull air across from the non-running fan opening, not through the rad core. Can you use the factory fan relay to run both at low speed and high?

948, i appreciate your feedback on the fans.

Are you still running the sock fans or did you end up wit the Spal 082?

The stock fans are segregated by the shroud. If i do end up running two Spal fans, i would just have them mounted directly up against the core with the rubber gasket i linked below to help seal.

I have been thinking about running the factory fan relay to somehow control the fans. It would actually be easier especially if i run the stock fans because all the wiring is still inact. So it would just be a matter of figuring out how to trigger the relay to kick on and off... i was thinking last night that the PCM's fan signal can be tied into the original fan switch connector using a generic relay to give low an high speed fans. The downside of this is i will be reusing alot of old components such as the fan relay, old wiring, fan speed resistors...etc.

One thing i wanted to try is sealing the fan up against the radiator core using the rubber gasket sold by Spal. You can see from the pictures in my earlier posts that the fan leaves maybe 1/8" gap against the core. As ive mentioned previously i think it only needs a little more 'oomph' to get the cooling system up to par. So i am hoping with the rubber gasket sealing the fan against the core and the slightly more powerful Spal 120 fan (slim straight blade) this will be enough. This is my plan of attack when i get home again next month, the slim straight blade fan is a direct swap for the slim curved blade i have on the car now, the gasket will require a few tweaks to the mounting points on the radiator, but overall shouldnt be too difficult to try.

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If you are talking about using the LS PCM to control the Porsche fan wiring, that is how mine are wired. Simple two wire connection.

Techno Duck wrote:
Are you still running the sock fans or did you end up wit the Spal 082?

I am back to the stock 951 radiator since my HMR (Ron Davis) 951 radiator died, on both i use the stock 951 fan set-up. I also have a second radiator in the nose of car.
I found, using a carb flow meter, that the stock 951 fans and shroud out flowed any other variation I made.
To measure the flow: I added a duct to the front of the radiator, out of cardboard, that narrowed down to a similar shape as the bumper opening. I then measured the flow in that opening. By measuring at the opening, not at the core surface, I was able to see the flow to the whole radiator for each setup.
If I had to do it again I would have spaced the 082 fans further away from the core, which would have likely given a higher flow rate. A quick internet search will give you an idea of the optimal spacing of the blades from the core.
From what I have seen/read it is important that any seal you use touches the core, a gap of even an 1/8" would reduce efficiency.

As mentioned, running the 2 wires to the OE relay is quite simple.

I'm starting to think my clutch issue is the same one that you were having. Every time I put it in first gear, I have to hesitate mid-throw or it will grind. Almost like something is catching as I move the shifter forward, and once it stops I can then shift. Just trying to mentally prepare myself for the teardown now..

Do you think it's something with the GTO cranks? Maybe they require a slightly larger adapter for some reason.

Supes, before you pull it apart remove the rubber cover on the transmission end of the torque tube that covers the access window for the driveshaft coupler. Start the car and have someone depress the clutch while you observe the coupler.. See if it stops spinning when you press the clutch. I just left my phone under the car recording video while I did this..   

Good idea.. I'll give that a shot before dropping the trans.

<snap> ... (in my family we must snap our fingers when we change the subject)

I just read a post on RL by you about your CCW track wheels. Can you give me the exact specs and style of them? Did they custom make them for you? What tires do you run?

I currently run cupII wheels from the back of a 993, 17x9 ET55 with 255/40 NT-01 tires. I'm thinking about 1" wider front fenders and 17x10 ET45 wheels all around. CCW seems like one of the few places to have such wheels made.

Thanks,
Rich

Rich, the CCW's are great and they are excellent to work with.

I have the CCW Classics with the track wheel options which are basically lightening holes around the wheel and no provision for center caps. The wheels are pretty light and are easily serviced or re-barreled through CCW. I had a set of Fikse's before this and ended up selling them because it was a real hassle to get them fixed. Price was quite reasonable i thought also, i think i paid $2200 shipped for the set of four when i bought them about 4-5 years ago.

The sizes i have are 17x9 and 17x10.5. CCW does not give the wheel specs in offset, backspacing only. When you order over the phone, just tell them your suspension / body mods and what widths you want. They take care of the rest in terms of offset / backspace. They were perfect, fits with no rubbing at all front or rear.

I am currently running 245/45/17 front and 275/40/17 rear. Id like to step it up to a 295 eventually, but most street DOT slicks have a weird profile at that size for 17's. Kumho does have a 305 width street slick but they are on extended back order last i checked.

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Thanks Jon. Glad your car is coming together. BTW, I just use stock 944 n/a fans.

Rich

Techno Duck wrote:Supes, before you pull it apart remove the rubber cover on the transmission end of the torque tube that covers the access window for the driveshaft coupler. Start the car and have someone depress the clutch while you observe the coupler.. See if it stops spinning when you press the clutch. I just left my phone under the car recording video while I did this..   

I finally got around to trying this - took a video with my phone.  Started the car, coupler not spinning, release clutch pedal and it starts to spin. Pressed clutch back in, coupler starts to slow and eventually stops. When I shift into 1st gear, the coupler slows down quicker but does not stop immediately.  I assume this is normal?  I can try to post the video if it would help.

It's possible I was pressing harder on the pedal than usual, maybe I'm not getting enough disengagement unless I really stand on it.  Could also be acting different once the car is warmed up.

I'm also wondering if it could be an issue with my short shifter or maybe 1st gear synchro.

What you explained sounds normal to me. First gear has always been temperamental on my car even after 2 different transmissions, i never engage it unless its at a complete stop. And with the torque from this motor its usually not necessary to use anything other than 2nd.

Fitted the Spal 16" straight blade fan with the rubber shroud gasket. The gasket has to be trimmed to fit the radiator profile; a little bit of trial and error fitment was all that was needed.

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Overall i am quite happy with how everything fits with the shroud gasket. The fan is now totally sealed around the core of the radiator. Have not been able to run the car with the fan yet, will complete the wiring tomorrow. I test ran the fan with two leads directly off the battery and it sounds like an air raid siren going off. The curved blade fan was fairly loud, i would say this is probably 10-15% louder!

The rubber shroud gasket raises the mounting depth of the fan slightly. The fan took some playing with to slide in and out of place, clearance with the tip of the waterpump pulley is tight!

Will report back with results soon.

Just under 1800 miles on the swap right now, right around 500 miles on the new clutch now. It is running great... car sat for a little over 3 weeks while i was away. She fired right up yesterday and hasnt given any fuss.. really loving the car!  

Looks good. I like the uncovered areas of the radiator, which should aid cooling at speed.

One warning for you, watch out for the spring-loaded serpentine belt tensioner. Mine chucked the belt off on the track. Lemming, Mark A and I have all gone with one of these:

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Rich

Rich, good reminder. Ive been meaning to 'upgrade' to the Katech fixed one.. if i remember right i was having trouble deciding what color anodizing to get so i never ordered. Are these the only types of problems i have to look forward too with the LS1?   .

Rich L. wrote:Looks good. I like the uncovered areas of the radiator, which should aid cooling at speed.

One warning for you, watch out for the spring-loaded serpentine belt tensioner. Mine chucked the belt off on the track. Lemming, Mark A and I have all gone with one of these:

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Rich

^ + 1

However, this could allow the belt to be over tensioned.

Is there a tool to allow the tension to be measured while being manually adjusted to prevent over stressing the limits of the shafts/bearings of the various components, e.g. alternator, p/s pump, water pump?...and if there is...what is the recommended tension?  (Like the old 944 timing & balance shaft belts.)