LS3 V8 Cayman!

So I went and bought another 06 turbo Cayman a few weeks ago. I bought it from another P-9 member with a blown engine. The reason I bought it was it had a lot of mods that I wanted for my car. So after taking some of the mods I have a complete car with a blown engine that I need to decide what to do with. Well after much thought and much more thought I had decided to swap the engine for an LS3 E-Rod. Reasons for doing the swap 1)430hp / 423 ft/lbs out of the box 2)2 year/50k warranty 3)replacement Porsche engine $10-$25k. Cost for the swap is around $18k (after selling the turbo and blown engine and a few other things I may get that down to around 8k) 4)Engine maintenance cost go way down 5)replacement engines LS3 crate engines cost around $6k 6)cost of future mods and upgrades go way down 7)50 state legal 8)Weight of the LS3 and 3.4l are very close 9)V8 power! 10)just sounds like fun Reasons for not doing it. 1)It's a one way street, can't go back to stock 2)It will be Porsche with a chevy engine, I think I just threw up a little in my mouth. 3)The conversion kit moves the transaxle back which will be wear out axles faster. So pushing aside my aversion to all things Chevrolet and just accepting the axels will need to be changed more often the only real reason not to do it is I can't go back to stock but I'm ok with that. I will be doing the work myself and should be starting next week so in the next week or two I will have a complete intercooled turbo kit that make 404rwhp and a blown engine for sale along with a few other odds and ends. stay tuned, this should be a lot fun! :dance::banana:

Woot! sounds like quite the project! A cayman with a LS3 sounds awesome. Are you custom making all of the swap parts? Custom motor mounts and such.

Very cool project. Scott Mann in Vegas has done a very trick Chevy Powered Cayman . Are you using his conversion components? I came very close to being his prototype car 3 years ago.

I'll be using the Renegade Hybrids kit. They seem to have all the mounts and wiring back into the DME figured out. I talked with a Scott but I don't know his last name. I was going to go down and check out the shop this weekend before I made my final decision but that fell through so I think I'm going to take a leap of faith and just order the kit tomorrow and order the LS3 when I get the turbo and engine sold. I've been following your build Driverdog, very nice!!! I almost had vision build me a 3.8l and you car came up a few times during the talks with them. In the end when I stumbled on the LS3 conversion I just couldn't pass on the uniqueness of the V8 conversion.

I'm interested to see your build as you progress! I've been waiting to see more results from Renegades white Cayman but have yet to see anything from it actually being on the road!

Please, please take good notes and pics along the way and post up a build thread. I've been watching and waiting for renegades cayman conversion kit to be finished. If my motor takes a dump, I'm going to go this route. I really look forward to your project.

wholly cow !!! :cheers:

Renegade is Scott's company. I've been to the shop several times and know Scott very well from PCA track events. They do very nice work and their product is well thought out.

That makes me feel better. When I talked to him he seemed like a good guy and really seemed to know what he was talking about. I was looking forward to coming down to Vegas this weekend to check it out but unfortunately I wont be able to make it.

This paragraph from RenegadeHybrids is interesting. "To increase strength, reliability, and performance, we have designed the Cayman kit around a Boxster S transaxle. The Cayman transaxle was engineered lighter with physically smaller gears and shafts, and the ratios were very short, which is not favorable or strong enough for the V8. The Boxster S transaxle has repeatedly taken abuse over 600HP in our Boxsters, 914’s, & kit cars, and we have yet to see one fail. Even the gear ratios and optional upgrades are quite favorable to the V8 conversion using the Boxster S 6 speed transaxle. We understand that this means you will need to source a good used Boxster S tranny from a salvage yard, but your Cayman transaxle has value equivalent to the Boxster S in many cases." Is he saying the 986 Boxster S transmission is stronger or the 987 Boxster S transmission is stronger than the Cayman 's?

The transmission thing caught me by surprise too and have not really decided what road I'll go down with that. I'm going to do a little research before I make that decision.

I just got off the phone with Renegade. I called them with the intention of ordering the kit but decided to hold off for a few days at least for a couple of reasons. 1st after talking a little more about integrating the the LS3 engine electronics with the existing Porsche electronics so that all the gauges and what not work correctly it turns out they are not as far a long as I thought after talking with them last time. 2nd lead time is 4-6 weeks and around that time I will be out of town for work so I might as well wait or week or two to order the kit. looks like this is going to take a lot longer than I thought it would.

Kidding aside, those Chevy motors are borderline legendary for performance and reliability. When I think of American cars a lot of things I don't care for come to mind (cheap interiors, unrefined suspension/handling, heavy, ugly styling etc), but I don't think I've ever thought of an American performance car and thought, man that thing is lacking in power. Assuming the clutch and transmission can handle the torque I think you'll actually have a real giant slayer. You'll really need a clear engine cover to show off your handy work.

I agree about the Chevy small block motor. LSx motors are legendary. LS7 would be the ultimate (that might fit). I think LS9 would be too much trouble to get in the engine bay. I've watched/read all the stuff on renegade's site about the boxster and 911s and can't wait for them to sort out the Cayman . I'm surprised to read about the Cayman transmission not being up to the task compared to the Boxster . I wonder what that is about. Just gear ratios??

As others mentioned, please document. I'm not buying the Cayman tranny is weak story, I know of several that have taken a pounding I high HP turbo versions without issues. AFAIK 2006+ Cayman / Boxster trannys are the same when comparing like cars.

I thought about an LS7 for about a minute. The price difference is the main factor. The LS7 puts out 505hp and runs about 16k, The LS3 e-rod puts out 430hp runs about 7.5k, I can get LS3 to 500hp for less that 1k.

Subscribed. My my friend is in the same boat as you. He reached out for more info and once he talked to the shop he didn't feel comfortable making the purchase. Sounds like a ton more R&D need to take place. And there is A LOT of cutting. I can only dream of a v8 powered cayman . I really hope you can make this happen.

I was under the impression that the 6 speed was the same. I have read a lot about Cayman power upgrades and this is the first I've heard about the tranny being weak. I'm leaning heavily toward using the Cayman tranny. I plan on documenting everything exclusively here on P-9. It is unfortunately going to be a longer process than I originally thought. I was really disappointed today when I found out they have a 4-6 week lead time. With that lead time it will probably be 8 weeks or more before I can start the install.:wall:

Scott's a good guy. He had his wife's "grocery getter V8 Boxster " (his words, not mine) out at Spring Mountain a couple of months ago for a track event / TT. I wouldn't buy a Corvette, but the engine itself is probably the best part of the car... nothing wrong with cheap, reliable, torquey power for the track... those engines are proven.

Almost all mid-engine Superlite SL-C's are made with either LS3 or LS7 engines. And most of them are made with the Porsche G-50 transaxle including the Superlite factory LS3 engine race car. I'm looking forward to seeing your build. Very exciting stuff! Sl-C Factory race car My car has a LS7 with a Ricardo transaxle.

I've been traveling the last few so I'm been out of the loop. Thanks for all tips and the great info!!!:cheers: Got started today but I'm exhausted from all the traveling so it seemed like a good to start slow and taper off. That basically means I got her up on jack stands and could not convince myself to do anything else. A few starter pics. Pay no attention to the mess in the shop, its just a figment of my imagination and if you ignore its not really there.

I got some stuff off the car and up for sale. I just posted a pedal box on Panjo to test drive Panjo. If that works out good I'll post some more stuff. I have a Durametric cable, a clear engine cover, a strut tower brace, a console lid, a CD holder, and a pair of amber side marker lights. I'll have a lot more stuff for sale including the turbo and engine as the project goes on.

I got the exhaust and the oil pan off. The oil pan was a little anticlimactic. I was expecting a lot of debris but there was hardly any at all. The cylinder in question is #1 and I cant see it at all from the oil pan. I also hooked up the durametric and poked around in the computer a bit. The car was over revved into range 4 so at least there is a smoking gun as to why it blew up.

My first one had a ton of metal in the pan, the second one had almost none as I shut it down very quickly.

Engines out!!! Up until now everything has been pretty basic but I had to get a little creative getting the stupid engine out from under the car. A couple people seem to be interested in the turbo and I'm talking to someone about the engine so hopefully I'll get that stuff sold soon so I can start ordering stuff.

Things are moving along! I have a solid offer on the engine depending on the damage so I'm going to tear it apart today and see what I am working with. We have a Summit in town and they have an LS3 erod in stock so as soon as I get paid for the engine I'll run down and pick that up. And later today or tomorrow I'll get the turbo stuff cleaned up so I can get some pics and get it posted for sale. I've settled on 4k if anyone is interested before I post it. It is %100 complete, every single nut and bolt associated with the turbo. It is inter-cooled with a 3rd radiator, has a Greddy boost controller, and cat back exhaust. One of the silicone hoses has a few nicks and should be replaced and the turbo compressor wheel has some very small nicks on a couple on the fins. I think they have been there a while so I don't think they are hurting anything. I took tons of pics of the removal that will come with it so installation should be a matter of following the pictures backwards

I reached out to Guard Transmission and got a surprising answer from Matt Monson: I'm not sure who told you that the Cayman 6spd isn't very robust, but they are mistaken. That gearbox was originally designed for the power and torque of an Audi 2.7l turbo diesel. The gears in it are wider than any other production gearbox that Porsche has made, except for the 930. The principal reliability problem with the gearbox stems from inadequate cooling and lubrication of the ring and pinion. Because it is midengine, the oil runs away from the diff, letting it run hot. After some time the ring and pinion let go. The solution is an external oil cooler of some sort with the return spraying directly on the diff. Sounds like you have already done this. Now from a performance standpoint, where the gearbox is "weak" is that even the factory LSD is darn neat useless. It has a 22/27 locking factor. From a traction standpoint you want basically double that. We can provide an LSD that does that. We can also improve the gearing on it, bringing the ratios closer together in 3rd-6th and doing away with the ridiculously high 190mph top speed it gets from the factory. Regards, Matt Monson Guard Transmission LLC [phone removed]

Gbox essentially told me the same thing, no problems with the box holding up as long as it doesn't get too hot or starve for lubrication, both of which can be easily dealt with, but from a strength standpoint it is plenty strong enough. Of course gear selection can be improved to suit your tastes.

That's great news. The weak tranny idea came from Renegade Hybrids website. I decided I was going to use the Cayman tranny anyway and take my chances. The concessions I was going to make where not installing an LSD and not running R comp tires but it sounds like with a few minor mods it should hold up. Thanks Driverdog! I haven't really had a chance to look into the tranny yet and that's big help. I am thinking hard about not using the Renegade kit and about making making my own. I will need to order some stuff from them like water pump adapter and the alt and PS relocation brackets but with a 4 to 6 week lead time on the kit and my work scheduled I can probably make me own before I got theirs and with the money I save I could get a TIG welder that I have been wanting! The down side is it would be a lot more work and trial and error on my part.

Well things have stalled a bit. I went the Mexico last week for my birthday and came down with a severe case of food poisoning and now I am about to leave for a work trip. I was hoping to get "phase 1" finished by now, getting the turbo and engine sold and getting some stuff on order but it looks like this is going to be a longer process than I was hoping.

Hope you feel better soon. Please keep us posted!