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Hi All,

I know this is probably in the wrong section of definitely the wrong forum, but I wanted to post here, as I have found this to be the strongest knowledge base of the bunch. I have been searching, but there doesn't seem to be much solid info on manifold flow differences.

This is for my B35 swapped Bavaria which I am considering turboing in the near future. I want to make sure to do most of the legwork up front.

I know that there are port size differences between B35 heads and older, same with the manifolds. Will putting an L-Jet manifold on a B35 cripple (sorry to be dramatic) the motor to a noticeable degree? I realize that they used the L-jet manifolds on the Euro motors, so I know they flow alright.

Essentially, I have both manifolds and set-ups ready to install into the car, but I have been vascillating while finishing up other parts of the project. Now, it is go time and I really am having a tough time deciding. What say you?

Thanks,
Scott C.

scarey013 wrote:Hi All,

I know this is probably in the wrong section of definitely the wrong forum, but I wanted to post here, as I have found this to be the strongest knowledge base of the bunch. I have been searching, but there doesn't seem to be much solid info on manifold flow differences.

This is for my B35 swapped Bavaria which I am considering turboing in the near future. I want to make sure to do most of the legwork up front.

I know that there are port size differences between B35 heads and older, same with the manifolds. Will putting an L-Jet manifold on a B35 cripple (sorry to be dramatic) the motor to a noticeable degree? I realize that they used the L-jet manifolds on the Euro motors, so I know they flow alright.

Essentially, I have both manifolds and set-ups ready to install into the car, but I have been vascillating while finishing up other parts of the project. Now, it is go time and I really am having a tough time deciding. What say you?

Thanks,
Scott C.

I will probably keep the ljet manifolds for my B35 build. Paul seemed think it would flow better at top end, giving up some low-end torque to the one-piece manifold.
I probably won't dyno it until mid November minimum but will release curves so you can see. There are plenty of B35 dyno sheets floating around already to compare.

b35 intake flows better than the m90 l jet intake.i tried them both in a m30b35 turbo motor.b35 ports are bigger.

lito wrote:b35 intake flows better than the m90 l jet intake.i tried them both in a m30b35 turbo motor.b35 ports are bigger.

Did you dyno both manifolds? I'd like to see where they were different

no dyno..im doing a custom intake now...short runners big plenum for my m30b35...will post dyno results after

lito wrote:no dyno..im doing a custom intake now...short runners big plenum for my m30b35...will post dyno results after

so how did you know it didn't flow as well?

FirstFives Dictator wrote:

lito wrote:no dyno..im doing a custom intake now...short runners big plenum for my m30b35...will post dyno results after

so how did you know it didn't flow as well?

The combination is e12 plenum (or early plenum), e21 runners and fabricated runner to head adapters. The stock stub adapters are much to small for the B35 head and there is not enough material to open them up sufficiently.

Of course a well designed manifold with a better port entry angle will make more power, this combination is the best of the OE stuff for loosening up the top end a little over the B34/35 type manifolds.

Paul

paul burke wrote:The combination is E12 plenum (or early plenum), e21 runners and fabricated runner to head adapters.

Paul

crap, I might be too lazy to do that....

paul burke wrote:The combination is e12 plenum (or early plenum), e21 runners and fabricated runner to head adapters. The stock stub adapters are much to small for the B35 head and there is not enough material to open them up sufficiently.

Of course a well designed manifold with a better port entry angle will make more power, this combination is the best of the OE stuff for loosening up the top end a little over the B34/35 type manifolds.

Paul

I have ported a set of injector stub manifolds to fit a ported B35 head and it can be done. They ended up pretty thin in places, but that car ran great. Then it threw a rod because the machinist that did the block didn't clear the oil passages. I was unhappy.

So you are swaying that George and I have to design a better manifold, too?

mooseheadm5 wrote: So you are swaying that George and I have to design a better manifold, too?

Ideally, we would change the entry angle on the head and then build an intake to compliment it.

I was going to suggest this to you Moosehead, well at least a viable fuel rail for the L-jet manifolds. Fortunately there is an injector that works for stock applications, but if you get out of that (turbo) I believe they need to be custom built. The injector clips for the new style injectors are around $30-35/piece which is another option. A solid fuel rail would be nice, though.

By the time your were done fabbing up the stubs, you might as well make a provision to use a B35 rail and injectors. At that point you could make new runners and...

So, why couldn't you reverse the stock L-jet plenum and fab some small straight runners to move the TB on the other side?

Ahh, time, money, talent...

In other news, I am not going to have a chance to port the stubs and they will go on the car for the time being. Once a get a chance to grab another set, a may blend them out. I am hoping, once this thing is running again, to have it dynoed to provide a baseline number for this combo. I don't know if I have seen any numbers so far for it. That is, unless Peter beats me to it...

mooseheadm5 wrote: So you are swaying that George and I have to design a better manifold, too?

Unless you stand the engine up you will never hit the optium entry angle with a straight (tapered) runner and retain any type of hood clearance

Paul

paul burke wrote:

mooseheadm5 wrote: So you are swaying that George and I have to design a better manifold, too?

Unless you stand the engine up you will never hit the optium entry angle with a straight (tapered) runner and retain any type of hood clearance

Paul

Dry sump with a new subframe.

There is always this way!!



Remember this one Rod ?

Paul

Sounds like you'll need to go ahead and make that head for George, then.

you might as well make a provision to use a B35 rail and injectors

This is what I did on my E9. It was a fairly trivial matter to fit them. I had to bore out the holes a little for the larger pintle caps, though this may not be necessary for certain style injectors. A couple of quick brackets to hold the rail to the stubs and the job was done.

So in conclusion,
"I assume this should sorta give you better top end flow somehow perhaps maybe. I don't know, sure, why not. do it"