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MG MGB Technical - PECO exhaust - installation tips?

1977 MGB, Weber carb. New PECO exhaust installation.

I'm looking for some installation tips on the PECO pipes. On acceleration, the connector pipe vibrates against the cross piece that has the jacking points. The pipe is obviously too close to the cross piece, despite the notch.

I'm thinking that resolution lies in rotating the connector pipe which is in front of the muffler. But before I take things apart I thought I see if anyone had other ideas.

Thanks for any suggestions.
Brian Denis

Brian. An exhaust system will not "knock" if properly stablilzed. I have the Peco system on two of my cars and do not recommend them.

Take your car into a good quality muffler shop and have them stabilze the system. Check with several mechanics in your area and see who they use for their exhaust system work. Then, take your car into the one most recommended and have them fit the system properly so that you do not have a problem.

Les
Les Bengtson

Brian,

I had the same experience as you. I could not get the supplied pipes to fit correctly. I went to the local muffler shop and for less than $80 they made a connecting pipe between the Peco header and muffler.

They adjusted the muffler and bent the pipes correctly. It now hangs perfectly and the muffler is much higher than with the original pipes. I love the sound, but the quality of the fit was very poor before visiting the muffler shop. When I have to replace the system, it will not be with a Peco system.

Cris
Cris DeYoung

Les, why do you not like the Peco? I have one on my roadster and while it was difficult to fit, it did go on and sounds wonderful! I'm planning to install one on my GT soon.
Steve Simmons

My findings on PECO systems are not that good, whilst I was working for their advertising agency I bought a system for my Mini, it sounded quite nice but did not last seem to improve the performance much. It also didn't last that long. It was only when I cut it open (to see how things work - my usual practice) I found that the pipe through the silencer was actually crushed and did not give a smooth flow though.

I had installed a PECO system on my first midget and whilst at that time (I was young) I thought the red system looked really good, I was disappointed with the performance.

When I started to chase the BHP we put it on the rollers and then swapped to a Janspeed system, immediately there was an increase in the performance levels, so I junked the PECO system and have stuck with Janspeed ever since for "off the shelf" systems. My race Midget runs a one off system that was specifically mage for the car (for a one-off price also I may add!).

Mostly it's a matter of preference, however the Dyna proved otherwise..

Andrew
Andrew

I was hoping the issue was finding the correct orientation of the two connecting pipes.

I've only have about an hour invested in getting them right... exclusive of the header and muffler installation. But I'm not getting positive vibes that things will improve.

I'll probably give it another go but use Les' recommendation of the muffler shop as the fallback.

Again, any other suggestions are appreciated, as are the ones so far.
Brian Denis

I don't know about Minis and Midgets, but Peter Burgess recommends the Peco above all others for performance. In the years I have run one on my '65 I have never noticed any performance hits or negative affects on the car.
Steve Simmons

Steve. Someone asked me why I did not recommend the PECO system a few weeks ago and I spent some time the problems with the system as currently supplied. Big problems are the paint, which does not stand the heat; flanges and spacers, of inconsistant size and not designed to mate with any known intake manifold; and fit, which always take professional help to get to work perfectly.

I have tested the PECO system on both an RB and a CB car. In neither case could I detect a performance increase when the new exhaust system was installed.

The PECO system is expensive for what it provides and the design and production is not of sufficient quality to justify the premium price for the product.

My latest car is using a spare, factory original, exhaust manifold and header pipe. Much easier to install than the PECO system is (especially on RB cars), costs less and seems to work just as well.

You can look in the archives should you want a full, piece by piece description of all that is wrong with the PECO system.

Les
Les Bengtson

I installed a Peco on my '80 LE. In the '70s and '80s when I ran Bs, I installed the Ansa system. It fit better and I liked the sound better, but could not find one this time. Does anyone know if this is still available anywhere? I recommend it highly over Peco if you can get one.

My system rattles also. One thing of note on all B systems is there is a connector that is supposed to hold the maifold header. It attachs to the bottom of the transmission bell housing. It has been removed on many Bs that I've worked on. You can find it in Moss and Victoria British catalogs.
Rick Penland

Rick, I'm aware of the connector from the manifold to the transmission, but with the increased diameter of the Peco header I wasn't able to reuse the old one. I improvised, but because it's at an angle I think it's not effective.

I'm figuring the that larger diameter of the Peco means less space to the cross piece, which leaves less margin for error.

I'll give it another go today, but Cris' & Les' recommedations are sounding pretty good.

Thanks to all who have shared their knowledge.
Brian Denis

Les, that explains why I didn't have a problem as you did. I am using the stock early manifold and down pipe with a Peco rear. The 2" pipe is welded directly to the end of the MG downpipe. So no flanges to worry about and I ahve that incredible Peco sound!

The paint is definitely bad, or at least it was many years ago when I bought my Peco. If I were to do it again I would either get a stainless system or strip and repaint it before installation.
Steve Simmons

Steve. Some things for thought.

The PECO header costs $228.95 from Moss and the rest of the system (what you are using) costs $266.95.

Yes, Peter Burgess does note that: "The best exhaust I have tested so far--in terms of quality, effectiveness and reliability--is the Peco HDR...Fitting one typically boosts the mid-range power by 5 BHP at the wheels."

He also mentions the header: "The Peco HDR exhaust manifold is a one-piece unit, appearing to copy the standard manifold design pipe lengths. Even though there's no easily measurable power increase from using it, even at high rpm, the manifold is worth fitting as it then mates very easily with the rest of the larger bore system.

However, earlier he states: "An instant mid-rang4e power gain of 2 to 3 bhp at the wheels can be achieved by removing the first silencer box from the standard system and replacing it with a straight pipe."

Thus, in the final analysis, we are looking at investing something over $500, plus having a difficult time fitting the system together, for a net gain of 2-3 bhp over the factory system with the middle muffler removed. It cost me $20 to have a muffler shop remove the middle muffler on my GT and fit a straight pipe.

I would never tell anyone who wanted the PECO system not to buy it. However, I can purchase a new header pipe and rear muffler, have them professionally installed and only spend about 1/3rd the cost of the PECO system. The difference in performance is, at very best, less than 5%. The sound is, with my old ears, identical. This is why I do not recommend the PECO system and, when one wants to replace the RB intake/exhaust manifold with a different system, my experience is that the Cannon header does not require you unbolt and lift the engine to install it. Unlike the PECO.

Les
Les Bengtson

I bought the Peco when I needed a new system anyway. I paid $179 (this is 5-10 years ago) when a stock replacement would have been just shy of $100. So for about $80-90 I got the Peco instead.

Performance is only one reason, and a minor one at that, why I bought it. I find the sound of the Peco HDR to be very nice. Low but not overly loud. I removed the center box (resonator) on my stock-style Falcon exhaust from my '67 BGT a while back to help the engine breath and hopefully lower the exhaust note. It doesn't sound anywhere near as nice as the Peco on the '65 does!

If money were no option I would still go Peco for the sound alone but there are certainly more economical ways to replace an exhaust system with a similar performance increase.
Steve Simmons

i had a peco large bore on my midget what a waist of time,when i had some work done at peter burgess he told me that a large bore system is not needed .iwent for a standard bore falcon with a performance manifold and to give it a nice tone i had 1 baffle box and 1 bullet box,you get a nice tone sounds like a v8 but is nice to drive at speed not like the peco.the whole lot in ss was around 200 pounds a bargain
daz

I installed a complete PECO system a week ago, and clearance beneath the crossmember Brian mentioned is indeed small, however, it only hits it when starting the engine. Took some time turning the tubes to find a reasonable installation.
Trying to fit an old header (used for 3 years) on my GT failed, as it seems to be warped, the rest was scrap due to rust. So much for quality. The paint develops a neat amount of smoke and smell when firing up the first time. But:
I must agree with Steve about the sound, it was the main reason for getting a PECO system again. (the other was easier installation of exhaust temp sensors in the front and rear header)
Jochen
Jochen Beyer

Rick Penland - I bought my replacement ANSA exhaust from these guys in Houston:

http://www.britishcarpartsco.com/

At the time, it was pricy, but then they last forever. (I actually made a mistake when I bought an entirely new system. The middle part had actually given up the ghost due more to the sagging rear springs than anything else. I replaced the rear bit, it turns out, unnecessarily. It went to a good home, though, now adorning a Bedouin B GT of a fellow club member in Windsor.)

Repeating the past consensus, the stock cast iron exhaust manifold IS a header design, optimized for stock and street applications. Its drawback is weight vs. other designs. I read an article years ago which did say that the PECO system is somewhat more powerful than most, but the objections Les noted were included in the article as well. The author ended up recommending a stock header, with PECO pieces aft.

John Twist has in the past recommended the Ansa, largely due to the sound.
John Z

This thread was discussed between 15/04/2006 and 19/04/2006

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