86 carrera LS1 swap

[911tracker85]

I did understand you but my question may be the problem.

from what I understand the RH cradle bolts up to the engine supports at the rear of the car. I had thought it then bolted up to the gearbox mounts in the front. but it is sounding like the cradle expects the gearbox to get bolted to the stock trans mount?

just read GM is now selling a new version of the LS7, wet sump and 570hp crate motor.....

[VacantSky]

Originally Posted by 911tracker85

I did understand you but my question may be the problem.

from what I understand the RH cradle bolts up to the engine supports at the rear of the car. I had thought it then bolted up to the gearbox mounts in the front. but it is sounding like the cradle expects the gearbox to get bolted to the stock trans mount?

just read GM is now selling a new version of the LS7, wet sump and 570hp crate motor.....

I’m following now, sorry my mistake! Yeah the cradle bolts to the stock engine mounts in the rear, but requires the use of the Porsche trans carrier. Maybe you saw MrRPJ’s build and his cradle like I initially did when researching this swap and thought it was the renegade one? (“..76 with 993 GT2 Widebody..”)

[911tracker85]

hmmm....

[VacantSky]

Minor update, finished my wiring harness adventure. BMW fuse and relay panel installed successfully in the smugglers box along with the odyssey battery. All systems check out! All relays are updated to Bosch style for mass availability. The rear sensor wiring I pulled out by the starter along with the wire to the starter solenoid. Using a deutsch connector the oil press, oil light, “oil” temp, and alternator exciter wires jump across a shorter route than before with the starter to alternator cable. Which coincidently is the remainder of my shortened battery cable, that worked out perfectly! Pretty sure I can fire it up currently, so I now have zero excuses to not cut the front tub for the radiator..! That will be coming up next.
The frunk looks so much better with the fuse panel relocated!

[VacantSky]

In regards to the clutch cable for a shortened 930 trans, I believe it will use the pt number for a long bellhousing 78+ 930 so I have that on order (930-423-401-09).

The 76/77 cable is a no go (I have one) along with the 915 cable. That leaves this one left..!

[dtakenname]

Hi,
Any modification plans for the gear box to keep the revs down ?

[VacantSky]

Originally Posted by dtakenname

Hi,
Any modification plans for the gear box to keep the revs down ?

I’m using a 930 4 speed, the gears are very tall. 3rd and 4th are both overdrive gears. Roughly about 2300 rpm at 70mph

[911tracker85]

when still planning to do the 3.3 turbo engine, the shop suggested I have the 930 4sp regeared. the wide ratios prevent keeping the turbo on a boil with the drop in rpm between gears. suggested I bring 2nd and 3rd in, and even 4th but that tends to get the cruising rpm high.

but with an LS and the wide torque range, no worries.

[dtakenname]

Originally Posted by VacantSky

I’m using a 930 4 speed, the gears are very tall. 3rd and 4th are both overdrive gears. Roughly about 2300 rpm at 70mph

Just an off topic question if you don't mind, do you think the gear box in the Normally Aspirated 997 is geared to not to rev too high if attached to LS engine?
Any info appreciated.
Thanks,

[Ryan_Cunningham]

Originally Posted by VacantSky

I’m using a 930 4 speed, the gears are very tall. 3rd and 4th are both overdrive gears. Roughly about 2300 rpm at 70mph

That corresponds exactly with what I've seen real-world with my shortened 930 LSD.

[Bigtoe32067]

Cheers to all the ingenious people in here not too afraid to tackle something this complicated.
I love to read about them so keep up the good work and please keep us updated. Some of us are living vicariously through your stories.
Thanks
Tony

[VacantSky]

Originally Posted by 911tracker85

when still planning to do the 3.3 turbo engine, the shop suggested I have the 930 4sp regeared. the wide ratios prevent keeping the turbo on a boil with the drop in rpm between gears. suggested I bring 2nd and 3rd in, and even 4th but that tends to get the cruising rpm high.

but with an LS and the wide torque range, no worries.

My thoughts exactly, the way the LS carries it’s torque across pretty much the whole curve will make it very “at home” behind the 930 trans

Originally Posted by dtakenname

Just an off topic question if you don't mind, do you think the gear box in the Normally Aspirated 997 is geared to not to rev too high if attached to LS engine?
Any info appreciated.
Thanks,

I don’t know what the 997 ratios or final drive are, but if you can find a similar gearing chart as what i posted but for those cars, or look up their cruising RPM’s that will be your answer. An LS crankshaft (or any engine for that matter) will turn the same revolutions as the Porsche one behind that trans. Hope that helps!

[Speed metal]

Your going to love this thing! Nice work

[VacantSky]

Well. I cut the hole.





This has been a slump for me, so hopefully this will get me back in gear to buttoning this thing up! The radiator looks more like an intercooler but it’s capacity is a little larger than the C5 corvette. And this will be a stock LS1. To feed it using my RUF valance I purchased a used boxster center radiator duct. It’s almost the same dimensions as the rad I’m using, and it’s mouth opening is the same size as the valance opening. With a little trimming and stretching with heat it should work a treat



So that will make sure the radiator is well fed, and a pair of fans will take care of the bumper to bumper and stop light airflow.

I think I figured out the clutch cable problem. The 930 uses a different clutch pedal arm/shaft. It sits at a different angle than the 915’s, and it NLA. So I’m figuring out a work around for that and will update when I can

-Kenny

[911tracker85]

where are you venting the air?

[VacantSky]

Originally Posted by 911tracker85

where are you venting the air?

I’ll be making a shroud like the RSR’s used behind a center mount oil cooler, but a little more exaggerated. Similar to this:

[VacantSky]

To follow up on the 930 trans in a 915 car, the 930 clutch lever arm in the pedal box sits at a more “rearward” angle. Unfortunately these are NLA outside of purchasing a used 930 pedal box. But if the bushing where the cable clevis hooks up ever fails and results in damage to the arm, you’re back to looking for a NLA part. To circumvent this I removed the bung it slots into (3rd pic with roll pin) on the clutch pedal and clocked it ever so slightly. Required some minor welding but I can say that it hooks up to the cable as it should now. And if the bushing ever fails and the arm gets damaged I can easily order a 915 clutch arm replacement and it’ll drop right in. First picture is roughly where it used to sit, second is the new position. It doesn’t look like much, but it’s on the money now!





It has since been removed and painted before the final install. I’ll be honest and say my measurement for the new angle was a precision guesstimate by installing the clevis pin in the arm and pulling the cable taught and marking the pin sleeve at the on-center of the clevis hole to note how far it needed to be clocked. But seeing as the engine/trans positioning in the engine bay is eyeballed and the 930 trans doesn’t truly just “bolt in” to a 915 car due to the torsion tube differences I should be able to make it work. It’s definitely damn close that’s for sure! (When I start to adjust the cable for clutch engagement I’ll make notes)

[VacantSky]

Still here, but life gets in the way and project cars can wait. The past couple months have gotten away from me. But I finally plumbed the cooling system in place.

The radiator hoses run down the sills of the car just like the original AC lines did and are held in place using adel clamps, they route through the aluminum crossmember not under it, better ground clearance but I need to space out the sway bar a little. I may end up with a through body anyways..

The water pump is mounted on the passenger side of the engine bay using a crude (but effective and out of sight) angle iron mount I made. I’m using a C5 corvette expansion tank above it mounted where the old oil tank hole is using a mount fabbed out of the remainder of the angle iron I had (that worked out great, and again is hidden). Both mounts are painted/undercoated. I may replace them with aluminum down the line but it’s negligible weight. For the rad hose I used a 25ft roll of flex-fab 1-1/4” silicone hose. Unfortunately it only came in blue, but it will be concealed when the car it sitting on its own weight at euro height so it’s not going to be an eye sore. Even with the car sitting on jack stands I have to get down to about wheel center to see them.

Next is exhaust and fabbing a shroud panel to direct the radiator air under the car (similar to the RSR panel pic I shared in an earlier post), the panel should be easy to do, and I have something pretty cool lined up for the exhaust using something intended for a newer 911.. and no it’s not a GT3 muffler! Oh and wiring the rad fans, they’ll be controlled by the Holley engine management! That’s really all I have left besides painting my rear bumper and RUF front valance.

Some pics







Some other things I have gotten to in the past couple weeks that aren’t really part of the engine swap but IMO are necessary for the engine swap is the suspension. The front has been overhauled with adjustable konis, 22mm torsion bars, new turbo tie rod ends, new ball joints, new strut mount bushings, and a “camber” strut brace. The rear is getting Koni adjustables and 31mm hollow torsion bars. All installed with some trick rebel s racing Teflon impregnated bushings. I have also had some very cool new wheels show up and had tires mounted but I’ll save that for the completed swap picture dump..

The end is in sight!

[VacantSky]

Rockers are off, valance isn’t fully mounted.. but I don’t care because the suspension is DONE. Just need some minor tweaks for height. But it’s almost spot on. I took my time reading A LOT of ride height adjustment threads and was nervous about the rear. Aside from the fact I had brand new components to work with, getting the rear indexing set was very easy and straight forward. USE THE ANGLE CALCULATOR! I got this first time.

Spoiler alert on the wheels.. Heritage 6 by MOMO.. F: 17x8.5 et30, R: 17x10 et20.

The rear has a very 917 look to it without the bumper and extension.. I like it!

[Yan2947]

Vacantsky, do you have a photo of your radiator hose going to the front as it passes the cross member? Your return is opposite side mirrored?