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View Full Version : Twin Turbo's for a BBC?



beached1
06-27-2001, 06:11 AM
Has anyone tried twin turbo's on a BBC. I'm thinking of going with it because I've seen what it can do on street applications. It will fit under the engine cover. I have a wife and a 3 year old. I don't think they would like it if I removed the hood and strapped on a blower. I'm running a early model 454 large oval intake ports. 9:1 compression. A mild L7 cam. The boat is just a cruiser but I just want to cruise a little faster. Anyway, I just wanted to get some feedback from anyone who might know about this appication or any advice you may have. I will make a decision this winter when I be removing the Jacuuzi WJ and installing an AT WJ energizer kit. Any advice is appreciated.

superdave013
06-27-2001, 07:44 AM
I ran a BB with an older Gale Banks tiwn turbo set up. It worked great. Will fit under your engine cover. Gets way better gas milage then my 8-71 did. Uses a small cam with a good smooth idle. And best of all, it's not very loud. At mid throttle it was runnig under vacuum and a full throttle it made 12 psi. I ran pump gas and got away with it. If you can find a good used one go for it. But a new Race Arrow set-up might cost as much as you boat.
I can send you a pic of my GB set up if you would like.

Gamer
06-27-2001, 01:05 PM
Hey Superdave what GB system did you have? Blow through or Draw through? And if it was a Draw through what carb mods were done to it? Or was it included with the kit. I'd appreciate any info.
I'm currently looking into the fabrication of a twin turbo setup for 455 olds. The motor is stock but recently rebuild 2 seasons ago. The current configuration is a draw through system running 3-6psi intercooled boost. Now before anybody asks why am I spending all this money for stock 455 olds that might blow-up. Well the truth is that I have a brother that works at Turbonetics and when the price is right "Free" or just about, I would think everybody would try to do the same.
Does anybody know who makes turbo kits for boats now?

058
06-27-2001, 02:27 PM
Gamer, You will need to boost reference the power valve for proper response. Without doing this the P/V will close or may not open at all when you need it the most, results: instant lean-out. Depending on the carb you are using you may have to experiment with PVCR diameters. Jet the pri. a couple of steps rich and the sec. 3-4 steps rich to start with. With the stock lower end of the Olds try to limit boost to about 4-5 lbs and run a 50/50 mix of 110 race gas/92 unleaded. Olds engines are very prone to detonation as they have very little quench area in the cumbustion chamber. If you are building the engine forged pistons are a must. Cast pistons will work ok providing you keep it from detonating and/or preigniting but are alot more fragle.

whitewater
06-27-2001, 07:26 PM
Check out Garett Turbo. Justin Boice who races in the Unlimited class In Whitewater jetboat marothon races runs a twin turbo charged big block. His last boat hauled some seerious butt. It was radared at a touch over 128 mph on the Salmon river in Idaho.

beached1
06-27-2001, 08:13 PM
Superdave013,
I would appreciate it if you could send me a pic of your setup. gerrit.costelow@attws.com The estimate I got from a friends race shop was approx 3k. I don't remember the make of the system but my friend has experience in installing twin turbos in every thing from sand rails to boats. I will find out the make of the system and get back to ya superdave and maybe you could let me know if 3k's worth it. Thanks for all the feedback guy's.