Which Exhaust

[dermotbell]

Hi
Although my exhaust passed it's MOT it has some corrosion and will more than likely not pass next years test.

So I was wondering which SS exhaust is the preferred.

I've read thro' the threads and seem to conclude that:
the Quicksilver is ill-fitting
the peco and piper are much the same?

I have a 90 SE (no cat) so would like an exhaust that sounds good but that doesn't suffer overboost. I guess the 2.25 exhaust is the best option?
I have an Everest chip, if this effects limiting of overboost (suspect it doesn't).

Looking for fellow SE owners to give me some insight to the best option.

Thanks

Dermot

[theelanman]

think youve answered your own question really....

piper and peco are the same people......peco got taken over/became piper....
2.25 seems to also be the size of coice if youre just running the everest chip.....
if youre going the whole hog with the LGM upgrade then 2.5......
so in summary.....2.25" piper system.......and they can fit it for you too if you live within a reasonable distance

[Alan_C]

Whichever exhaust system you fit, unless it's a standard Lotus steel system, expect to get overboost. You'll be a lucky s*d if you don't! Essentially I think Lotus realised the turbo couldn't dump enough exhaust gas through the wastegate on full throttle once they'd tuned the Isuzu engine, and rather than de-tune it they restricted the exhaust by squashing a flat area in it. Remove the squashed area and you've now got a free-er flowing exhaust, change the pipe for a larger bore makes it even more free flowing, which all means the turbo can spool up and run faster. With only a tiny wastegate hole, the boost runs away untill the ECU shuts down the fuel. Once the exhaust has been changed, at least you know the nuts on the downpipe will be new and not siezed, so if the turbo has to come out to be ported, it's one less set of siezed nuts to worry about! Getting the turbo off actually isn't all that hard, I had cause to re-port mine recently - remove, re-port and replace took 4 hours, and the porting was very in-depth this time round, lots of gas flowing just to be sure!

[dapinky]

piper and peco are the same people......peco got taken over/became piper....

You been to the pub again Gareth????????

PECO became CYBORG - PIPER are the other ones!!!!

The rest is right though!

either are good (I personally love my PIPER, and would recomend it over the PECO, but others with a PECO would take the oposing view).

PECO is only to be had in 2 1/2", PIPER gives the choice, and is much more 'modular' so you can have what you want.

I use a 2 1/4, single silencer, with PCE and think its the dogs danglies.

[theelanman]

You been to the pub again Gareth????????

no just got it wrong.......

I never followed the peco thread really as Id already had a custom one fitted.....
I just remember that it started with benkyboy and the peco and then they went bust or something and then a similar product appeared from piper just as there was talk that peco were being made by someone else......1+1 = 5......
you know me n maths

oh and I never got over boost after changing my exhaust for a 2.25" system.....

[dermotbell]

IIRC the OEM is a 2 inch exhaust, so there must be some risk with a 2.25.

So is there any way to limit the risk?

Dermot

[steve matthews]

On the Fed. car with pre-cat and main cat removed.
2 1/4 peco installed. Overboost will show up on cold damp days
9 out of 10 days.
The Everest tones down this happening.
By the time the Everest hits fuel cut you are going tooooooo fast anyway.
Steve

[MPx]

Just had four sessions at Castle Combe with a 2.25 Piper with PCE and just a sports cat and there was no overboost today at all. I did port it to ~20mm tho...!

[Mike_H]

There is a company called Double S Exhausts that make a stainless copy of your original exhaust so you wont have to worry about porting the wastegate .

http://www.stainlesssteelexhausts.com/index.html

Mike.

[theelanman]

mmmm........
Ive heard several reports of the SS (double s) exhaust......non good Im afraid......
however this maybe down to local fitters.......
its been a fettle and see type of exhaust from what I gather...it has never seemed to be an easy job for the fitter is what Im getting at and then its never seemed to be 'right'

just going off what Ive heard but theyre all about the same price so I suppose better the devil you know......piper/peco that is
piper will do you one at 2" if thats what you want.......
theyre all about £300~£350

[rip]

I think Lotus realised the turbo couldn't dump enough exhaust gas through the wastegate on full throttle once they'd tuned the Isuzu engine, and rather than de-tune it they restricted the exhaust by squashing a flat area in it.

I don't think that's the reason..

I have heard 2 reasons for limiting the power:
Lotus deliberately restricted power to 165bhp to reduce torque steer.
The other reason is that they restricted max power to ensure that the Elan could not lap their circuit faster than the 'flagship' Esprit.
Either way, the wastegate & stock exhaust are nicely matched: It needs to open almost to max in regular use to maintain controllability.
Enlarge the exhaust & you upset this balance.

Having said that, With my Piper 2.25" exhaust, unmodified wastegate & adjusted timing, I have only got overboost in cold weather & the exhaust gives a nice performance increase & sounds great without being too obvious.

[steve matthews]

Agree, after obtaining more than 55 hp on the dyno Ican live with
occasional over steer and boost creep.
Steve

[ksgrimsr]

Hi
Although my exhaust passed it's MOT it has some corrosion and will more than likely not pass next years test.

So I was wondering which SS exhaust is the preferred.

<snip>

I'm using the Piper 2.25 setup that includes the sports cat (they have a couple different configs) as well as the Piper PCE on my FED car with an Everest chip. It's nice setup and performs/behaves well. I'm sure there are other quality setups as well, but I'm very pleased with the Piper and wouldn't hesitate to recommend it.

Knut

[dermotbell]

Guys

Thanks for the info and comments. I think I may well go for the Paul Matty 2 inch system that Matt Don is selling as I am keen to avoid boost creep as the car is an every day vehicle and I think this would get tedious.

Dermot

[ksgrimsr]

Guys

<snip> ... I am keen to avoid boost creep as the car is an every day vehicle and I think this would get tedious.

Dermot

I realized that I wasn't clear in my earlier post. For the setup I installed I haven't suffered from boost creep. I get the impression from the postings that boost creep is a little bit variable across vehicles and configurations and I'd be curious where the edge lies as I'm sure folks anticipating exhaust upgrades may be interested.

On my car with the 2.25" Piper with main cat included and a PCE, I got modest overpressure with the stock chip as I could tell the boost gauge readings were a bit higher than before the exhaust change, but I never managed to get enough pressure to reach cutoff. With the Everest chip everything looks exactly as advertised. With the modest overboost I observed before changing to Everest, I suspect I was on the edge and that if I had selected the 2.25" Piper setup without the cat or the 2.5" Piper setup that I'd probably be past the edge.

From other folks that have done exhaust changes, are there commonalities in how far you have been able to go before going past the edge on the overboost (requiring the waste gate to be ported)?

Knut

[steve matthews]

Dermot, you have the potential to realize the power locked up inside your Elan.
Boostcreep is the result of a HEAVY FOOT. It does not show up every time you
gas it. Leaving the pre-cat and main cat alone will certainly increase your odds
of not. Tough decision, I went for the H.P.
Steve

[dermotbell]

Steve
As I have an SE I don't have a CAT so this is why I think I would suffer from boost creep, and I do have a heavy right foot.

The majority who don't have creep seem to have the CAT which restricts airflow so maybe this is why??

Dermot

[rip]

I'd be curious where the edge lies as I'm sure folks anticipating exhaust upgrades may be interested.

Firstly, I refer to boost creep as any boost over the ecu's target (in the case of a stock ecu, anything over 0.65bar). Boost creep is great!
Overboost is when the ecu goes into safety mode. Overboost is bad

Ok, I've got a Piper 2.25" system with the extra silencer on my UK SE, so no cat.
I have the stock ecu & downpipe.

I had an issue with my timing. With the base timing set at 16btdc, I got overboost at about 4000rpm, sod all power & the car was not very driveable.
I have now fiddled with the timing & found that at 32btdc the difference is amazing. I get boost creep quite a lot but only get overboost in cold weather & when I'm doing around 6000rpm with my foot hard down, which is not very often at all.

[Axel-F]

Ok, I've got a Piper 2.25" system with the extra silencer on my UK SE, so no cat.
I have the stock ecu & downpipe.

Having stock ecu is an important point, as everest chips seem to help to control overbost,
But also may be sport cat is more restrictive to gaz than silencer, so it also tend to avoid overbost on a 2,25 line?

[rip]

Having stock ecu is an important point, as everest chips seem to help to control overboost,

Sort of.
Everest ups the overboost cut-off very slightly (0.95 from 0.94 IIRC), but the difference between target & over boost is so small you are not likey to see boost creeping on the gauge in time to back off.