My friend came across this on a forum for Buick Grand Nationals, and I thought it was pretty cool. Must sound pretty damn good too! Purists might want to skip this post. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
I think the builder was actually describing the nature of the modifications to the engine as far as choice of turbos, etc. Not necessarily "GN" parts per se... Bill, the engine is out of an F355 (not a GN), and as far as I can tell from what the builder was saying it also has the 355's 6-speed transmission.
So that's the 3rd "358" that we know of so far. The Blackhorse 358 GTS (not a GTO replica) The Japanese one with the F1 tranny (GTO body and Daytona seats) and this one. Pretty cool. Wasn't the guy who owned the Blackhorse-modified car planning to do a similar conversion with a 360 powerplant? Of course, there's no photos of this motor actually IN this 308
Been there - done that. The easy (and cheap) part is done, ie assembling the parts, the REAL challenge is the development of the car to make sure it runs properly, doesn't tear up transmissions, blow head gaskets etc... For every $ you spend on parts you can add 2 more for development... Good luck, need a lot of patience and deep pockets!
i do know that turbonetics is a big supplier of aftermarket turbos that are used in gn's. i also do know of some twin turbo buicks that have gone in the 800hp area under 10 psi. if i can find the link ill let you guys know.
looks like my numbers were a little off....well, alot off. they have the buick engines around 5-600 hp running high 10's at 18 psi. i mustve gotten it confused with a supra or something, who knows, but here's the link. http://www.turbobuicks.com/forums/showthread.php?t=42915&page=1&pp=15&highlight=esp+twin+turbo
Hello everyone! I am the person (along with Sean O'brien) that built the twin turbo 355 in these pictures. The car is originally a 308 that had a 288 body kit installed on it (in California by a previous owner, so the story went) They had twin turbo'd the 308 engine and it really was pathetic. The owner at the time of the mod (I don't know the where abouts of the car currently, but it was shipped to Norway and after that I haven't heard a word from the owner) brought the car in to have some exhaust work done to it. After he became familiar with our work, he wanted to re-build the engine and upgrade to current EFI and a better turbo system. After we had the engine removed, he called and said to "STOP!"....We said too late guy it's already out! He said "GOOD" but don't do anything with THAT engine because I have just bought a 355FI from England, and I want you to install that engine in it AFTER you twin turbo that one. You 'CAN' do that can't you? We said we could and the project began....that is the waiting part, in that it took for ever to get the engine through customs (The customs folks didn't know what it was and maybe they thought the cylinders were full of cocaine or something<grin>) To make a three month story short, we recieved the engine, trans axle, rear frame assy., brakes, AP multi disc clutch, and assorted hardware and wiring. We started by cutting the rear frame apart and then setting the stripped down engine in place to get the motor mounts fabricated, and get an over-all veiw of the project. The intake manifold was retained, but the plenums were fabbed to resemble (loosly) an original 288GTO. We had a detailed model of a 288GTO that we used to build everything to closly resemble it. (THAT was VERY challenging!) We had a company back east (I have forgotten their name, fortunately for them) build the wiring harness to (hopefully) save us some time. It turns out we SHOULD have built it, because they REALLY screwed it up. We elected to use a Motec-M800 ECM as we were promised plug and play with the original Ferrari sensors. That info was not true and if I were to do it over I would have used a F.A.S.T. or Big Stuff 3 ECM instead. The Motec is a great unit but has WAY too many features that the owner really didn't need. It would have been easier to convert to AC-Delco sensors and use a FAST system. If you have a ton of experience with Motec, then stick with it, but we usually use FAST or Big Stuff 3. (being back-woods kind of people<wink>) So, with the engine in we set about to build the headers from stainless and purchased t3/t4 hybrid turbos from Turbonetics, along with wastegate and blow-off valve. The intercoolers are also from Turbonetics, along with some plumbing supplies. The entire wiring harness was removed and replaced with a Painless Wiring universal kit, and the whole car was rewired. The console was fabbed from carbon fiber and has dual adjustable brake valves plummed into the console, It also has a mechanical brake valve under the seat for a parking brake, as the brakes do not have a parking brake feature. The day we had the 355 brakes mounted on the car, the owner called and said NOT to install them, because he had purchased F40 brakes and they were on the way! So, off came the 355 brakes and then new adaptor brackets were engineered and fabricated for the F40 radial mount calipers. (the brakes came off a car that had caught fire so we had to rebuild all the calipers due to SERIOUS leakage). The only bolts that would work for the caliper mounts were "ARP" Mitsubishi engine main studs, and we had to machine down the nuts to fit the recess of the caliper. The oil system also proved to be challenging in that the fittings in the oil pan and block were metric and had to be fabricated by welding AN fittings to Kubota tractor compression fittings. This was the ONLY fitting I could find that had the correct thread at the time. No one had -16 AN to metric fittings. The oil pan was removed from the engine and oil drain fittings for turbo oil return were welded into place. There are two air to oil coolers for the dry sump oiling, with the stock 355 oil filter retained. We removed the heads and head gaskets and installed a custom set of dead soft copper head gaskets, that were .090" thick, to lower compression as a temporary fix. If the compression fix didn't work we were going to have Cosworth or JE build us a custom set, but for now the owner wanted to save a couple of bucks and wait to see if the stock pistons could handle 12-15 psi boost. The clutch discs needed to be relined. The flywheel they sent with the engine was not the right one, and the starter was incorrect, also. We recieved the correct starter, and then had to fabricate a ring gear adaptor. The ring gear came off of a Cadillac Cimmeron (I believe) and the adaptor was machined out of billet steel. We had the adaptor balanced so it would be able to rev to 12,000+rpm (the owner stated that the Ferrari tech dept. told him that the engine was capable of 12,500rpm, and he "WAS GOING TO SEE IF IT WOULD!!!!") The fuel system was another challenge in that the stock 308 fuel tanks wouldn't work. We installed an ATL road race fuel cell in an aluminum crash box up front, along with an Aeromotive EFI fuel pump and regulator. We used a Griffon aluminum radiator with modified 308 aluminum transfere plumbing. We installed a roll bar and the stock interior. Racing seats were used also. We also fabbed a complete stainless muffler and exhaust. The turbo system was a quick disconnect, and could be removed in less than an hour, and in it's place it could run normally aspirated. The owner wanted this so it would be easier to get the car imported into Norway. Apparently, they tax you based on horsepower or something along those lines. The car was a REAL pain to get running. The wiring harness was completely pinned out wrong and the factory sensor couldn't be read by the Motec unit. The owner ended up taking the car to a California tuner to get it started. (Sorry, I do not remember his company, but he DID help out ALOT) I was at the time transitioning back to an Areospace job and didn't have 14 hours a day to go through the system. I had figured out the pin-out problem (late one night after work) but the owner (who is a trained electrical engineer) said that the pin-outs were fine the next day. I didn't second guess him. He trailered it to California and the guy there spent 36 hours figuring out the problem (he has alot of Motec experience and supposedly built a turbo'd 355 with Motec, so he was the logical choice for help) He did get it running and we then set about to get it running on all cylinders. One half of the engine wasn't firing, but it still ran great! with a 180* crank it sounded like a mean four cylinder. After a little bit of programming changes, it ran pretty damn good. It would fry the tires at 50mph and wouldn't stop until you let out of it. The owner was VERY happy. BUT, business sent him back to Norway, so into a container it went and off the Europe it went. I'd love to hear what actually happened to the car as I have OVER 500 into it and Sean had probably 750 hours in it. Kinda long winded, sorry. I have left out a TON of issues we had to overcome building it, but I had alot of fun and would do it again in a minute! This time a little easier, for sure! Ken
Here's a pic of my twin turbo Buick T-Type: http://turbobuicks.com/forums/showthread.php?t=53720 Here's a pick of the Rolls-Royce Griffon I use to build: http://www.airventure.de/reno2001pics/reno01pmengine.JPG Ford 5.4 four valve sheet metal intake: http://turbobuicks.com/forums/showthread.php?t=60542
WOW...thanks for taking the time to type all that, Ken! All in all, a very interesting story. If you have any more pictures of the 308/355 please feel free to share! Your twin turbo GN looks SICK, by the way!
Here are more pictures of the build: Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login