Federal Exhaust -- What do I have and what do I do?

[Hegg]

Alright, exhaust is pretty new to me (having never had a turbo and never really cared), so I'm getting a little overwhelmed reading all of these threads.

First of all, this is what's on my car right now:
http://unabled.com/show/cars/m100/8-Exhaust/

That's how I bought it. My first question was about the "squish" over the subframe (picture #2), but it sounds like that is a "stock" squish. It seems debateable about how much it affects performance, and Dave Bean locally indicated that it shouldn't have much affect. (http://lotuselancentral.com/forum/viewtopic.php?p=75559#75559 and http://www.asnu59.dsl.pipex.com/elan/pictures/exhaust/squish.jpg as references.)

It appears to be a 2 inch system all the way back. The muffler has been removed and the car is a little loud for my taste (sounds more like a riced-out Honda than a hand-built Lotus). Performance seems pretty darn good to me, but I'm coming from cars that don't have any performance (1968 Ford Falcon, 1980 Triumph TR7).

I also came across an unplugged connector as you can see in picture #4. What's that go to? Also, is this the pre-cat that I'm seeing here? It seems like the best thing to do with that pre-cat is this. Anyone recommend or not recommend that?

Next, does my catalytic converter look stock? I don't know what a stock one looks like, so I'm not sure if the P.O. removed this one and replaced it (judging by the multitude of welds near it). I'm also wondering what type of performance benefits I might get from a high-flow catalytic converter. And, if I did, would I negate any benefits by putting a muffler on the end of the system (to quiet it down)?



So, in summary:

(Q1) Is the "squish" worth removing? My exhaust shop seemed to think it would be more work than it's worth.

(Q2) What is the sensor that's all bundled up in my 4th picture? Is that supposed to go to something? I don't appear to be the only one, as techlectic mentions it here.

(Q3) Is it beneficial to get a high-flow catalytic converter and replace the one that's on there?

(Q4) How much restriction would I be causing if I put a muffler on the car? From what I understand, the catalytic converter causes restriction of the gases, but the muffler (mostly) just redirects sound waves and should cause a whole lot of restriction, especially if you get a "performance" style one.

Thanks again in advance. Y'all are great!

[Doug]

Well, your system looks USA stock to me, except the straight pipe instead of the muffler.

Yes, the old factory squish--probably there more to make a system to fit every Elan than needed in the system--since the cars vary a slight bit, I'd bet they squished them on purpose to be sure clearances were good enough to keep the pipe from rattling on the crossmember. We know from experience that you can make a 2 1/2" pipe go thru there fine without a problem!

That's the EGT probe on the pre-cat. It's not hooked to anything on the USA cars and is just extra on a few. Yes, you can hollow out the pre-cat like your link, but to go to all the trouble to remove the pre-cat to do it would probably necessitate getting a new system (you'd break some bolts/welds/etc).

Bottom line, from what you seem to be saying, I'd say either (1) leave it as is or maybe just weld a muffler on the back, or (2) do the whole deal and gut the pre-cat, make a 2 1/4 or 2 1/2" system with flex-joint at the downpipe to keep it from breaking ( common Elan fault is to break the weld on downpipe from engine twisting/torquing it there ), high-flow cat for emissions, and then muffler or not to suit your aural pleasure . . .

[Hegg]

So would you suggest that making changes such as a high-flow cat and/or hollowed pre-cat wouldn't help much without getting some bigger pipes on there in the first place?

Just curious -- like I said, I'm new to exhaust mods.

[Doug]

yes, you can do it but it won't "help" unless you change the whole thing -- otherwise it is still a less than 2" system from a resistance standpoint

going from that to 2 1/2" would nearly double the volume for exhaust flow


you've got a rusty old system -- it will have to be repaired and/or upgraded at some point in the near future, so decide where you want to go with it and we can help you figure it out.

wouldn't cost to much to just weld on a muffler and forget about it in the meantime until the downpipe breaks or you want to drop that ESM chip in there!

[Hegg]

Very good points. I think I'll leave it as is probably until later this year -- I can live with it until then (as far as not having a muffler goes). But I see your points regarding replacement of the whole sha-bang. Thanks for the informative feedback!

I do have an Everest chip in the car already.

[Hegg]

Oh yeah, and I was gonna ask, is it sensible or foolish to get a high-flow catalytic converter off eBay?

They've got quite a few for cheap!

My brother just picked one up off eBay since they seem to be significantly less expensive than buying one through "the regular avenues". Or do I want to go with something specific? If something is off eBay, what kind would work best? Obviously I wouldn't expect something to just "bolt on", but I don't think $1,317.00 for a catalytic converter from Dave Bean is the best route, either.

[Hegg]

Oh yeah (boy, I say that a lot), Dave Bean also suggested a Dynomax Turbo muffler. Any comments on that?

[algirdas]

Dear Hegg:

I'm in a similar situation as you. I have basically a stock system on my car. I have decided to go with the Peco 2 and 1/4 stainless steel system. They are currently working on a sport cat solution and should have it available in the next few months (more money unfortunately). Since I am in no hurry, I can wait, but at least I got in on the group buy on the basic system. Plus, I have had experience with Peco products on my 1971 Elan. Their products truly are high quality stuff and worth the money, in my opinion.

Here is my current plan (anyone reading this thread feel free to chime in with suggestions. I do not profess to have a monopoly on good ideas.): I'm probably going to fit the Peco exhaust without a cat and see if the pre-cat is enough to get me past emissions. If it passes, great. If we develop a stiffy II for A/C equipped cars, then I'm probably going to try and see if I can pass emissions without any cats (I guess I'll know then whether there is any truth to the urban legend that cats don't work at altitude (I live at 5,000 feet-Ft. Collins, Colorado)). If I flunk the emissions test with no cats, then I will probably get the sport cat from Peco and put it in. If it passes emissions with the sport cat-great! If not, then I will be looking for an emissions station with a greater degree of moral flexibility and a larger margin of error in their testing equipment.

These are my long-term plans. My current system seems to be working okay for now and I have a spare downpipe in case mine breaks (BTW-if yours ever fails unexpectedly and you are in a real pinch-call me, its yours until you get things sorted out).

What do you think?

Sincerely,

Algirdas

[algirdas]

Dear Hegg:

An alternative would be to just put a Borla muffler on it.

Sincerely,

Algirdas

[Hegg]

I saw the posts regarding the PECO system, but figured that the shipping costs from the UK to the Rockies would be prohibitive. Do you already have yours? If so, what did you pay all said 'n done?

Next time I head to Colorado, I'd love to see your '71 Elan and your M100!

[algirdas]

Dear Hegg:

I got in on the group buy at 250 GBP. The guy at Peco (Dave or Peco Dave to those who know him well (just kidding)) is looking into shipping costs at the moment and I soon as I know them, I will pass them on to you.

I know that the shipping from the UK can be ridiculous. I was thinking of picking up the system on my way back from Stoneleigh this fall. I was planning on just taking an extra pair of underwear in my coat pocket and two empty suitcases for car parts.

I realize that this may raise some eyebrows going through security or at customs. I guess I could always tell them that they are nuclear bomb parts and see what they do. On second thought I better not. In this post 9/11 world these people just don't have a sense of humor any more and they may make it so that I can't drive any of my cars for 10 to 20 years.

I'll ask him if the freight gets any cheaper if we send two at once.

Also, the next time you are passing through Colorado give me a shout. Better give me some advance warming since I am a bachelor and I live like one. I may need a few weeks to do some cleaning/remodeling/demolition before the place is presentable.

In addition, don't forget that LOG27 is in Aspen/Snowmass in August 2007. That is so close to you, you really have no excuse for not being there.

Sincerely,

Algirdas

[Doug]

pardon the truth, but only a fool would ever buy a cat for $1000

that, I assume, is the "Lotus OE" part? what a joke!

you can get name brand hi-flow perfectly working cats for $100-200 from what I recall

[Doug]

here's a quick dirty link to prove my point about name brand universal cats

http://www.sportcompactonly.com/product.aspx?p=101138&c=100019&l=2

those ones on ebay are obviously crap!!





http://www.car-sound.com/catalog/universal/500.aspx

[GeoffSmith]

Hegg,

Ailwyn has asked Peco Dave to look into providing a cat solution for his S2, as he wants to get a stiffy and would obviously loose the pre-cat. I'm hoping we can come up with a solution before Algirdas gets over, as it would be well engineered (the standard Peco fits like a dream) rather than a chop and weld bodge. This would benefit both Fed's & S2's and hopefully it would provided the facility for easily removing the cat for track days like the exhaust Peco do for the Elise.

Keep an eye out on the Peco thread for progress.

Geoff

[Hegg]

So... I was just thinking.... It doesn't look to me like the Pre-Cat is even 2.25 inches to start with. If that's true, what good does it do to enlarge the pipe after the pre-cat?

And as a 2nd question, does anyone know if the PECO system can sell just the muffler (that's what you folks call a silencer, right?)? That seems to be a reasonable size to actually ship to the US without taking out a 2nd mortgage.

Thanks again, and sorry to bring this back up!

[GeoffSmith]

Hegg,

Sorry, but I forgot about this thread. I've started a new S2/Fed cat thread which you may be interested in.

I don't know whether you will gain anything by buying the back section of a Peco as the pipework will be a different diameter and you'll end up needing some welding done. If you can wait a month or so, Peco should have completed the development of their cat system.

On the issue of restrictions in the exhaust, length is important! A short length of narrow diameter pipe may restrict a lot less than a long length of wider diameter - try blowing through a straw and a hosepipe.

Geoff