SC 3.8 Revisited.

[Rhunadan]

Re: SC 3.8 Revisited.

Is the blower on these cars a roots type blower? If it is, why wouldn't I be able to close off the intake at the back and machine a new one at the top like a traditional roots blower you see on bigger motors?One could weld in a flange at the top and run a manifold from it to the TB. I won't have a chance to get a blower till the weekend to see what's possible.

[Oldsaddict]

Re: SC 3.8 Revisited.

I just got done doing this swap on a 99 Firebird. For about 4-5 years I have planned to do it just to see what is involved. I have found 2 other builds that actually ran and were complete but wasnt crazy about the blower setups. The lower intake manifold is almost up against the firewall, there is about a fingers' worth of room between the inlet of a stock fwd M90 housing and the firewall. The Holden housing doesnt really help anything because the cast elbow that bolts to the inlet of the that housing still sits back too far and will run into the firewall. I took tons of pics along the way as I planned to make kits as there are quite a few guys out there that ask about this. With everything complete I decided it simply isnt worth the time, cost, difficulty to do this project. I modified an M90 housing and made a custom inlet tube that goes over to the passanger side just the few other guys did (mainly because you cant shorten the blower housing up and not run into the boost bypass valve on the drivers side). Other than the wow factor, and yes it is something different, I cant justify building another one unless someone has to have it. Turbo is a much easier and more powerfull option to go. You still have to factor in a transmission rebuild and torque converter to handle the higher power, better driveshaft, rearend, subframe connectors, torque arm, rear suspension work.... the list goes on. I think for a fun 13 second car the M90 has appeal, but again the time and cost really puts a damper on those plans. I too played with turning the intake manifold backwards but it hits the front engine cover and you cant machine enough off of either to make it fit without some custom fab and welding and then you get into the coolant passages on the intake. turning the blower around seemed like a good idea also and running a jack-shaft with the pulley and intake on the front side just like what Magnuson does for many rwd applications. The most logical and cost effective option I decided on was to shorten up the inlet quite a bit and build a custom elbow. I have about 1" of room between the inlet elbow and the firewall. There is almost no room above the blower, barely enough for fuel rails. I used an L32 fuel rail and modified it slighly to fit the mounting studs on the intake as it is turned backwards. This is a returnless type fuel rail so a regulator had to be mounted in line with the rail on the car and I used an L67 regulator cut out of that fuel rail which works fine. I could write a book on this swap, nothing really went the direction I had hoped and I definately give props to anyone who successfully gets one going with a clean look. To those on the fence, plan on months of work and iron out the little things and fabricating parts that have to be used, it is not a weekend project. I really thought it would be a good project to tackle and something we could offer as a kit, but there is just too much more to it than that.

[Rhunadan]

Re: SC 3.8 Revisited.

Well I have the blower now. I think I'll be doing something similar to Oldsaddict but I want to try and keep the TB on the driver's side. It may fit if I get rid of the ABS. The L67 was sold and hour before I called my buddy and said that I wanted it:(, so I'll need to get my hands on a lower intake and see if I there's room to drill and tap injector bosses in it. This will let me keep my heads. I'm starting to get very excited now;)

[97rs4life]

Re: SC 3.8 Revisited.

you can drill injector bosses into a l67 lower intake. just look at the zzp m90ss kit for the l36 cars. they drill the intake for injectors so you don't have to swap heads

[Oldsaddict]

Re: SC 3.8 Revisited.

The throttle body cant be put on the drivers side with the setup like what I did and the other few that have done this because of the boost bypass valve actuator and thermostat housing, just isnt enough room. If you did a bit of fabrication to the blower housing on the passanger side to get the bypass valve actuator on that side and kept the thermostat housing very low then it would work. I have the inlet tube on my 86 L67 swap Cutlass on the drivers side but I did a lot of modification to the firewall to make room for it. Its pretty cramped on the passanger side with everything but is the easier option. As mentioned above the injectors can be plumbed into a lower L67 intake manifold just as the ZZP SSM90 kit uses but this also requires some modification to the blower housing and using ZZPs billet fuel rails and not sure how this would fit up with a blower housing that has been modified for a rwd application. Swapping out the heads isnt that much of a chore once you have the engine tore down to the intake anyways and if you plan to put heads on then it is also easier since everything is apart. In the big picture it is much cheaper to swap the heads and use a stock lower intake and stock type fuel rail especially if you are doing all of the work yourself.