Hey everyone, I’ve got a long time project that was starting almost 10 years ago. It’s a Mgbgt with a s5 6 port. I’ve got a few ideas on how to turbo it but would love some feedback. The main problem I’m facing is turbo placement because the engine very low and far back in the engine compartment. The only way to get a turbo under the hood would be to run the manifold piping under the frame rail into the wheel well and then back into the engine compartment through a hole in the inner fender. I would have to cut away more of the passenger footwell fit a downpipe past the intake and redo the fuel lines to move them somewhere else. I’ll also have to find a way to support the turbo and manifold if I do it this way. Because of this I’ve really been thinking of doing a remote or rear mounted turbo behind the drivers seat right before exhaust exits out the side. Obviously there are some drawbacks to this idea as well but I’m really considering it. Advantages I can see are less fab work, it’s different much like this whole car, and the added will placed lower and in a fairly optimal spot. Disadvantages; there would be a straight thru muffler placed before the turbo to keep the noise somewhat reasonable, 6.5’ long exhaust manifold piping compared to maybe 2’ long if mounted up front and self contained oiling system which actually may not be a disadvantage really other than more parts to buy. Third option is to just leave it N/a. Power goals are not too high 280-325hp would be plenty in this car, it’s very light. Engine has been streetported on both intake and exhaust ports and also has functional 5 and 6 port actuators (I’m curious if they will make a difference in spool). So to summarize my main question is how much of an affect will the long exhaust tubing have? And what would you do with turbo placement?
Also this will mostly likely start out as a blow-carb setup which I have good experiences with in the past. It may transition to fuel injection individual throttle bodies to replace the dellorto.
Thanks
Caleb

 

Can you move the engine too the left a bit? That might help getting the manifold runners through for a top or front mount.

 

Wow! Talking about 100lb of…….”stuff” in a 2lb bag.

The carburetor manifold is built for N/A application. As such it sticks way further out from the engine than a 13B REW manifold.

Switching intake manifolds will certainly help with the lack of clearance issue.

 

I'm currently shoehorning an S4 block and turbo into an MG so I feel your pain. The way I see it, you have two options that are reasonable: Mount the turbo forward in front of the engine and push the radiator forward or do what I did and literally cut out the majority of the factory frame rail and scab on a new frame rail on the outside edge so you can mount it in the factory location. Your downpipe will definitely be weird and your passengers will have a foot warmer:







Forgive me for the mess and pay no attention to the radiator, after years of half assedly MIGing parts for mock up to then send out to a real welder I decided to start learning how to TIG. Ugh.

 

Yeah I see you know what I’m taking about lol. Wasn’t expecting someone to be doing almost the same thing. There’s very little room between the frame rails for a rotary. I‘m really surprised you were even able fit the turbo that low even after cutting away the frame. My engine mounted a little lower and slightly further back in the bay. I’ve actually already had to move a section of the firewall out in the same that you cut out. But anyway in my case there tons of space to put the turbo in the engine bay, no need to move the radiator or anything. Its really more of problem of all the exhaust routing. Both options have pretty long runners. Also with my wheel/tire combo there’s not much room to reinforce the frame if I modified it.

 

The lower intake is a stock s5 six port manifold. I’ve seen one piece manifold out there but you lose the port actuators which I’d like to keep. But it’s an option.

 

Definitely no room to move it. The steering column is very close on the other side.

 

Referencing the rear most passenger side subframe bolt and your front intake ports we're actually almost identical fore and aft, and the centerline of the engine is a straight shot back to the diff so I'm actually pretty sure we're basically in the same spot, I've put on an FB front cover and am mounted with a plate on the back side of the subframe using the rear lip as a shelf, you?. What you may not see is that I've also cut out a whole boatload of firewall and stitched it back up to fit the engine and FD trans and its fatass bellhousing.

With regards to the exhaust routing just don't try and go under the frame rail with a 3" exhaust, its one of the reasons why I've gone side exit even though I've gotten the room by punching into the foot well.

 

You’re right they’re pretty close to the same spot. I had to modify the sub frame and then made a mount to the frame rails.
In regards to the exhaust, yeah definitely not enough clearance to go under the rails. I made my exhaust come right through the body on the driver side. Had to modify and reinforce the frame there as well. This is why I want to do a rear mount turbo, perfect spot right there before it shoots out.