Porvette

 

1. All LS non racing engines having oiling issues if cornered hard. The problem is anytime you exceed 1G of cornering for more than 5 seconds, the crank is starved for oil. It is just a poor design of the oiling system. The LS engine that have bank to bank breathing don't have any better lubrication, they just keep pressure from building up at the ends of the crank. Hence why rod and crank bearing issues are common track failures on all LS engines. 2009 Z06 and later Grand Sport models got a 3 quart larger oil tank that improves, but does not resolve the issue. Best way to fix it is an aftermarket dry sump system or upgrading oil pump on cars with factory dry sumps (Z06 and Grand Sport)
2. LS7s have issues with the sodium filled exhaust valves breaking, particularly with larger cams. Hence why all the head builders who build up LS7 head use SS valves. The Titanium intake valves, made by Delmar, are extremely durable. The weak sodium filled exhaust valve problem exists on all the newer LS engines.
3. The cast iron cylinder liners in the LS7 engine use non-ductile iron. Basically, the liners aren't malleable and will crank under high stress. If the cracking is not caught early, they will damage the aluminum block making it a $3300+ paper weight. Common building practice when building up a LS7 engine is to have the block sleeved with Darton sleeves. Darton sleeved block easily survive being pushed 1500+ HP with ARP hardware. This problem is really unique to the LS7 block. Most junkyard builds (<800 hp) use truck iron blocks to avoid block strength issues.
4. Stock LS7 pistons are low silicone hyper-eutectic. They are fine NA, just don't push a lot of nitrous or boost on them.
5. LS7 Titanium connection rods are actually quite strong. The bolts that are attached to are not. Any rebuild should include a set of ARP 2000 rod bolts.

 

I wouldn't do it, but it's amazing how well the conversion works... definitely an interesting video to watch.

A BMW e36? Yes, definitely!
I've ridden in a stripped e36 with a wildly cammed V8, wow did it sound good and it chirped the tires shifting into 3rd!

 

There was a guy at one of the recent local DE’s who brought in an older aircooled 911 with one of these V8 conversions. It was really weird watching the car and hearing it make low-frequency V8 noises instead of the customary flat 6 sound. Not a bad thing, just different. The car appeared to be fast until it blew up part way through the first day. I have no idea who did his conversion, so this post isn’t an attempt to knock Renegade or any other company.

If you’re looking for a way to talk your friend out of doing it, the biggest downside is probably resale value. A car with this type of conversion will be viewed as a Frankencar by many potential Porsche buyers, and would likely have to be sold at a big discount.

 

^^^ I'm not trying to talk him out of doing the Vette engine in a Porsche...I want him to make the correct decision so that we both have trouble free fun at the track.

 

in that case find another 3.4 or 3.6 and call it a day. A days labour actually.

Vette motor transplant require alot moar messing around. Fuel system. Guages. wiring.... and on and on...

Better off taking a vette engine and stuffing it into an affordable clean 67 camaro and then mod/track the hell out of it.

I have two LS-1 engines and T-56 transmissions and have not bothered getting around to stuffing them in something yet, but an affordable 67-68 camaro would be it. 69s' are up there in price...

 

Not GT3s but....

We have a good customer with a 986 Boxster S that we have serviced and modified over the last couple of years. The car will be back with us in a few weeks for more mods. Since we last saw it the car now has an LS7 in it, done by Renegade.

To be honest, I can't wait to see it and drive it.

We have also had a 944 with an LS3 in. We had a bunch of small issues with that install we sorted out for the owner, but it was fun too.

Those that know me understand I am a Porsche fanatic, love my aircooled cars and really like the latest watercooled stuff as well. But I have to say I am very intrigued by the performace/dollar equation of LS7 and 986..

With the owner's permission, we will post some pics

 

^^^ thanks Jeff!

 

One thing the Renegade video didn’t cover very thoroughly was the impact of the extra length of a V8 in a rear engine layout. I know that the modern LSX engines cram the cylinders pretty close together, but so does Porsche in its modern 6 cylinder engines. So it would seem that having 4 cylinders on each side of the engine would still result in a longer motor overall that a flat 6, which only has 3 cylinders per side. In addition, the V8 will need an adapter plate to blot up to the flange of a Porsche transaxle, and that will also add a bit of extra length.

That extra length won’t matter much in a front engine car that had an in-line 4 cylinder or in-line 6-cylinder engine to begin with (e.g., 944, e36, e46, etc.), and also shouldn’t matter in a mid-engine car (e.g., Boxster, Cayman, etc.), but it seems as if it would make a bigger difference in a rear engine 911. Porsche increased the wheelbase of the 991 by a very tiny amount, and they also pushed the engine forward relative to the back wheels by a very tiny amount. Those tiny changes are said to yield handling improvements for the 991 chassis. If true, then it seems that adding an extra few inches in the other direction would have some negative impact on handling. I have no personal experience driving one of these cars, so my comments are based purely on first principle considerations. Maybe there’s some implementation trick that Renegade or others use to get around the effect of extra rear overhang.

 

Here is a 944 with a LS3 watch to my disappointment as I loose a drag race down Millers full front straight in a NASA race and I have 510 RWHP

 

 

Don't know about fitting it in a 996, but an LSX block is barely any longer than a flat 6. What a lot of people forget is the size of the flat 6 cylinders. Because they have additional spacing to support space for air cooling, the block is a lot longer than a traditional V6. The only fitting issue renegade has with putting a SBC, LTX or LSX in the back of a 911 is the accessory routing. Because the rear crossmember interferes with the accessory routing, all the accessories have to be mounted on the bottom. Please note that the same issue exits with the original flat 6 and hence why Porsche put the alternator under the intake manifold. Bottom line, there really is not an engine length issue. Also realize that individual cylinder to block design also adds weight. Think about this, here are the actual weights of several common engines:

440 lbs - 911 S/C 3.0L Flat 6
440 lbs - Ford Coyote 5.0L DOHC V8
440 lbs - GM LS7 7.0L Small Block
444 lbs - BMW M3 4.0L DOHC V8
449 lbs - GM LS1 5.6L V8 (aluminum block)

The other key thing for final engine placement is the transaxle that is used. Renegade highly recommends using a Short Bell 930 transaxle for better engine placement to maintain stock weight distribution. Go with a Long Bell 930, G50/50, G50/52 or G50 6-sp and the engine has to move back impacting the weight distribution.

Looking at the cost to rebuild an older flat 6 in an old 911, I personally have no issues with anyone swapping a V8 in these cars. With a 996+ though, it just seems backwards to me. Those cars come with modern DOHC variable valve timing engines that spin to 7200 rpms. Putting a low revving OHV V8 just doesn't seem right. Putting an LS1 instead of a 3.6L Carrera engine in a 996, doesn't really give a good performance improvement. If it is a fresh motor, it only has the same power as a 3.6L 996 X51 engine; but is hindered by poor gearing. At 100K plus miles, they are down quite a few ponies and potentially have no more power than the flat 6 that comes out. The 996 transaxle gearing simply isn't right unless you are going to build a big cam, big head, high-revving LSX to utilize the gearing. Of course if you did this, the newer 996 transaxle can't take the power or torque. Hence why I am really confused why you would do this to a 996? If it was a modern Boss version Coyote V8 that spins to 7500+ rpms, I think this would be fantastic in a 996 chassis with a far more compatible rev and torque range. This is kind of like what Ruf did putting a 4.5L modern DOHC V8s in 997s in Europe. My $.02

 

Hmmm, I wouldn’t have guessed that an LSX is the same length as an M96. According to a quick search, the LSX motors have 110mm bore spacing as compared to 118mm for the Porsche motor. A bank of 4 cylinders with 110mm spacing should be longer than a bank of 3 cylinders with 118mm spacing, close to 4 inches unless I’m missing something. Then add in the thickness of an adapter plate (if you want to retain the stock transaxle, as the car in the video is said to have done), and it seems like quite a lot compared to the tiny forward placement of the 991 engine. What was the 991 placement, 1 in forward compared to the 997, or thereabouts? Porsche claims that’s enough to yield a measureable improvement in the handling of the 991. If so, then even 2 or 3 inches the other way can’t be a good thing.

I agree with everything else in your post – a low RPM torque hog may not suit the stock gearing of a 996, the durability of the transaxle, or the high-revving character that many 911 owners like so much. But I can see where the allure of low-cost replacement motors would be attractive to someone who just blew up an M96 – an engine that I’ve heard isn’t designed to be rebuilt and is increasingly expensive to replace with crate motors from Porsche.

 

now youre talking!

 

A LSX is 24" from outside of crank pulley to the block surface on the bell housing side. What's the length of a M96 engine? An older Flat 6 is over 23" from the rear crossmember mount on the engine to the bell housing surface.

Here are a couple really good pics showing an LS3 in a 83' SC. Not exactly crammed in like you would initially expect.



...vs a stock 911 Carrera engine:


It looks more crammed into a 996:




...but then a stock M96 looks crammed in a 996: