6 replies to this topic

[Chris.Williams]

Morning guys and girls,
I'm considering replacing my log manifold with the maniflow straight through version
http://www.maniflow....54&product=1100
Has anyone had experience with these, eg is it worth it's?
I read on here about the short falls of the log manifold and these seem like the only real different replacement.
My engine is a metro 1275, stage 2 head, twin 1.25 Su (obviously) with MED stub stacks, full rc40 exhaust, Evo 1 cam with balanced and lightened internals. Currently produces 82bhp and 78 ftpb of torque at the motor.
Cheers for ya help.

[carbon]

Chris, not sure what you mean by a log manifold, is this the standard twin carb inlet manifold?

 

The Maniflow twin carb manifold is reckoned to be one of the best performing twin carb inlet manifolds currently available. But the standard inlet works fairly well if you carry out the mods as detailed in Vizards book.

 

Out of interest, which rockers are you using with the Evo 1 cam? And above 85bhp you're getting towards what is generally considered the limit for twin HS2s, are you planning to change to HS4s with the Maniflow inlet manifold?

[Chris.Williams]

Chris, not sure what you mean by a log manifold, is this the standard twin carb inlet manifold?
 
The Maniflow twin carb manifold is reckoned to be one of the best performing twin carb inlet manifolds currently available. But the standard inlet works fairly well if you carry out the mods as detailed in Vizards book.
 
Out of interest, which rockers are you using with the Evo 1 cam? And above 85bhp you're getting towards what is generally considered the limit for twin HS2s, are you planning to change to HS4s with the Maniflow inlet manifold?

Yes, sorry log being the standard manifold, I had not looked at my bible for manifold mods, this is a good plan.
I'm running the standard sintered rockers at the moment, and mulling over getting 1.3 rollers from MED. I read the Evo1 doesn't need 1.5 rockers as it has a high enough lift.
I had thought about HS4s, yes, but won't change if not needed. It pulls well all the way up to 6750rpm on the dyno.
Peak torque is at 3500 and is basically flat through to that higher rpm. Awesome torque!
But always looking for that something more haha.

[imack]

I swapped from an internally modified bmc manifold to the maniflow manifold with twin 1 1/2" su's on my previous 1380. It isn't an absolutely straight swap. Firstly the bmc carb to manifold studs don't fit the maniflow manifold as the flanges just have plain holes in them that are too large to tap for the bmc studs. You could probably nut and bolt them, but I turned up some mushroom headed interference fit studs in my lathe. Secondly there's no where to mount the throttle cable bracket, so I welded an internally threaded stub to the manifold to mount the existing cable bracket. Thirdly the carbs required different needles after replacing the manifold as the fueling requirements were quite different. Admittedly that engine had never been set up on a rolling road with the bmc manifold but 'appeared' to run well and I only guesstimated the replacement needles for the maniflow setup.
I did think it felt better with the maniflow manifold, but I was unlikely to have been getting the best out of either set up as it hadn't been setuo on the rolling road.

[Chris.Williams]

I swapped from an internally modified bmc manifold to the maniflow manifold with twin 1 1/2" su's on my previous 1380. It isn't an absolutely straight swap. Firstly the bmc carb to manifold studs don't fit the maniflow manifold as the flanges just have plain holes in them that are too large to tap for the bmc studs. You could probably nut and bolt them, but I turned up some mushroom headed interference fit studs in my lathe. Secondly there's no where to mount the throttle cable bracket, so I welded an internally threaded stub to the manifold to mount the existing cable bracket. Thirdly the carbs required different needles after replacing the manifold as the fueling requirements were quite different. Admittedly that engine had never been set up on a rolling road with the bmc manifold but 'appeared' to run well and I only guesstimated the replacement needles for the maniflow setup.
I did think it felt better with the maniflow manifold, but I was unlikely to have been getting the best out of either set up as it hadn't been setuo on the rolling road.

Yes I saw that the mount for a throttle cable was missing, figured I do the same as you've done.
I think they sell a stud kit to suit.
I've had mine on the rollers, and is set very nice, I to thought mine was running good.....till it was tuned, then WOW

[imack]

You can just about see the studs I made, &and the throttle cable mount I welded to the bridge tube.

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[imack]

Yeah, had my current engine set up by peter baldwin runs so much better.