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MG MGB Technical - Are headers worth it?

I will be changing my exhaust in the spring. I have an old Pacesetter with a broken plate in the resonator, the rattling is driving me crazy. When I do change is it worth getting headers? I was thinking of the Peco system sold through many of the catalogs. If it is worth it is there a better system out there. I do have the Weber DGV carb conversion now. Thanks.
John

Not worth the effort or expense, moreso with a DGV
gerry masterman

I think of it more of a cost per HP type of thing. If you need a new exhaust you can pick a beter flowing exhaust for about the same money. If you need a new header (exhaust manifold) I think a pecco one would be cheaper than a new standard one. If you replace it just to gain beter breathing it may well cost £100 and that would probably work out at around £75-£100 per extra bhp.
So if your replacing just for prformance I would not bother, go for a beter air filter (£25-£30 for 2-3 bhp)
It is a personal type of thing , if youve already done the filter, a big bore exhaust then a new header may be the way to go. If its a standard car I would not bother changing it for preformance. I am no exspert on MG engines but have found in other makes (BMW 3.0 csl, porsche carera 911 l/weight, jag -etypes) that stock exhaust maniflods are pretty good, and you need to spend an awfull lot of ££££ to get beter.

hope this helps
marc
M C Lovell

John. What type of exhaust manifold do you currently use? That would, for me, be the deciding factor. Since you are running a Weber DGV, does this mean you have a rubber bumper car? If so, if you are using the original exhaust system, with the intake portion cut away, you may find it useful to change. I have the Peco system on two cars and would not recommend it, especially on an RB car. The Cannon header is easier to install and I can see no peformance differences between my Peco equipped cars and my Cannon equipped cars.

The factory supplied exhaust system, up until they went to the single carb, seems to work as well as the headers and, due to its design, it forms a tuned exhaust system. I would not consider replacing a CB exhaust system with any of the custom headers.

As to mufflers, any good muffler shop can fit you up with a new one, you do not have to go with a whole new, specialty system if the head pipes are in good condition. When I needed a new muffler back in 81, when there were still BL dealers offering service, the BL dealer in Austin advised me to take the car to Midas for a better muffler at a lower cost and a better warranty. Les
Les Bengtson

I remember putting HS4s on my '76 B as part of a modest engine upgrade. I had a header on it but the exhaust noise was getting to me, so I switched to a stock manifold and exhaust - ready to compromise power for some peace and quiet. Surprise! Guess what? With the stock system, the car was both louder and faster. Go figure! - Allen
Allen Bachelder

I went for the matching set of Maniflow intake/ exhaust manifolds. Along with a free flowing ported head, I figure I have the best flowing top end a guy can get. Haven't dyno'd it, but there is improvement over stock. My advice, you must match the components with other performance upgrades to get results.
Brian Johnson

The way the car is set up now is a Weber DGV carb with a Longflo foam air filter. It has the stock manifold with a Pacesetter exhaust (the exhaust has a broken plate and rattles which is why I want to change). I figure if I'm going to change the exhaust I might as well think about a header. Thanks for all the input.
John

For the most part headers don't really provide much more HP than a stock manifold unless the stocker is horribly designed and the B manifold doesn't appear that kind. Generally headers cause the bottom end to get mushy because of the reduced backpressure. Save your money.
Mike MaGee

The stock B header is well designed. You won't get much except a dent in your wallet unless you've made radical changes to the engine.
R. L Carleen

The Special Tuning manual says that the biggest gain from using a header is from decreased weight. I went with a 2" system with one turbo muffler and the stock manifold. Effective and cheap - a good combination.
Glenn

Ditch the foam air filter before you burn your car up from a backfire
gerry masterman

I've never heard that about the Longflo foam air filters. If I swith would I be better off with maybe a K&N filter?
John

In general, foam filters either filter poorly or restrict flow, sometimes both. The ones with perforated chrome covers flow badly, because there is very little open area unless the filter is HUGE.
You haven't told us what "stock" manifold you have or what year the car is. If it is the 2 outlet early B one, then you will see no gain with a header, and possibly a low end loss. Most headers are too big for a basically stock engine, many are also poorly made, giving both too low gas speed at low RPM, and bad flow at high RPM. (It is gas speed that makes smaller pipes work better at low speed, not backpressure, which is always bad) If you have a good reworked head, and a hot cam, and use high RPM, then a good header can help, but not much. The cast iron manifold is also much quieter and more durable. If you have a chopped off late B ex manifold, then anything else that fits is better.
FRM
http://www.usachoice.net/gofanu
FR Millmore

I went with the cheap header from Victoria British. then had it ceramic coated, inside and out, locally. [Minneapolis/St Paul, MN]
It's just as quiet as a manifold, and very nice looking. Way lighter, and seems fairly efficient.
I would like to know if the Maniflo intake really has performance gains. You know, PROOF!
Safety Fast
Dwight McCullough
Dwight McCullough

This thread was discussed between 02/09/2004 and 05/09/2004

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