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MG MGB Technical - APT and fab'd SU Intakes

Does anyone have any experience with these? Their price seems "right" and their theory seems sound. I'm concerned also with clearance after phenolic spacer (since heat transfer with steel intake) if there is room around a late model brake booster.

Luke
Luke Staley

My wife has a Mitsubishi Mirage, daily driver...92hp, 2500 lbs, and about a 3.20 final drive ratio...my 67MGB has 92 hp, weighs 2200lbs, and has a 3.90 ratio...and the Mirage accelerates MUCH harder...whats wrong with this picture?
BobTSC

Luke,
I have one and the dimensions are the same as the factory manifold so you will have the same clearance problems as any twin SU setup on a late B.
Leland Bradley

Bob,

Acceleration is to do with torque, not horsepower and the ratio you need to compare is the overall ratio, not just the back end.
Chris at www.octarine-services.fsnet.co.uk

Luke-
I presume that you're talking about a Maniflow intake manifold. In a late model integral servo-boosted car you'll need to use the K&N conical airfilters. They're also available from APT (part #SD36). Be advised that these are for the SU HS4 carburetor only. The Maniflow intake manifold is a high performance item for the SU HS4 and the small surface area of the conical filters makes them a bit restrictive, so it's an "odd couple". You might consider changing the pedal box, pedals, and master cylinder to those of the earlier non-boosted system and sacrificing the servo boost so you can run proper size filters (3 1/4" deep, Part #SD23-319) to match the flow potential of a high performance motor.

Bob-
Run a compression chck and tune the engine. Somethings amiss if you can't beat a Mirage!
Steve S.

The Maniflow intake has a center balance tube that a welder can install a vacuum take-off for your servo hose . Also the heat shield requires a major modification for your throttle linkages to clear when using the thin phenolic insulator blocks in conjunction with the Maniflow in order to gain clearance for the rear carb in relation to the servo. That said with the right cam profile and proper porting of the intakes on the head, the engine will scream past red line when using the Maniflow with some power sacrifices at the low rpm. Steve's suggestion would be the better way to install the Maniflow intake on the later rubber bumper cars with left hand drive. Then you could install the monster K&N's with velocity stacks.
Andrew in Austin

I have the Maniflow intake manifold on my 1962 B with HS4 carbs. The last time I looked, it appeared to me (and a mechanically inclined friend) that it took up a little more space than the stock setup. However, I'll try to remember to actually measure it against the original intake manifold when I get home this evening. Incidentally, while the air filter that Steve mentions may exist just for the HS4 carb, it should perhaps be clarified that the Maniflow intake manifold is available for both sizes of carb, HS4 and HS6 (and HIF4 and HIF6). Finally, as to performance, my car is very strong with excellent low-end torque, but because so many things were done to it, I can't say what is attributable to the Maniflow intake manifold.
David Cushman

OK, I measured the Maniflow this morning along with the stock intake manifold for the 1962 B. The
Maniflow extends about 1/2 inch further from the engine. The consequence in my case is
that the front (standard) air box slightly rubs the insulation on the hood. Since I didn't put this together myself, I can't say whether any modification had to be made to throttle linkages and so forth, but this may depend on the year of the car.
David Cushman

Everyone speaks of either cutting down the phenolic spacer or acquiring a shortened spacer from Moss. What is the original thickness of this spacer? Would a .350" spacer from APT help me in the rear spacing issue or is the Moss piece thinner yet?

TIA
Luke
Luke Staley

This thread was discussed between 02/10/2001 and 05/10/2001

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