245 BHP for £1000 and perfect delivery!

[simonbuk]

All this stuff about turbos, chips and boost but not much talk about heads ?

Has anybody ever done any development on heads ? Anybody do porting work ? Maybe not worth it when the cost of a chip is so cheap for 40 odd bhp gain ?

[lotusflasherman]

All this stuff about turbos, chips and boost but not much talk about heads ?

Has anybody ever done any development on heads ? Anybody do porting work ? Maybe not worth it when the cost of a chip is so cheap for 40 odd bhp gain ?

Keith Duckworth objected to turbochargers coming into F1, not only because they were not allowed under the existing F1 regulations, but because they would not advance the design of engines as anyone could take a badly designed engine and wind up the boost to get power from it - 'tuning by screwdriver' he called it.

If you are going to do some serious modifications to head castings you need to know where the various waterways are and what the variations between individual castings are likely to be or you'll end of with just a lump of scrap.
Playing around with turbos, chips and boost is much easier and cheaper - and if you get it wrong by going too far and affecting 'driveability', going backward towards standard set up is much simpler/cheaper.
I've done some work on the head of the 2.2l (912) engine in my Eclat when I was rebuilding it, just a bit of 'blue printing' - port alignment and port & combustion chamber polishing but never had an Elan engine to pieces.

My gut reaction tells me that if the NA gets 130bhp at 7,200 rpm and the secondary throttle doesn't open till 5,200 rpm the general breathing of the inlet tract in standard form must be pretty good so any improvement by blueprinting would only be marginal, particularly when compared to the gains available from increasing boost with adjustments to fueling to suit and letting the exhaust get away with an improved system. Much easier 'tuning by screwdriver'.

[Simon_P]

There is a massive step in the inlet tract around the injector housing. It looks like they shortened the length of it without changing the angle.

The top and bottom do not align so correcting it would require removal of material from the top of one casting at the top and the bottom of the other casting at the bottom. Do this and you have a dramatic increase in cross section area right by the injector.

Without testing you couldn't tell if the existing step is even detrimental.

All rather proves Mr. Duckworth's point

[simonbuk]

Thanks, and yes I guess once your turbo'd it's the easiest thing to tackle/improve.

Can't believe an exhaust change takes it to 200 bhp though. Normally a 15-20 bhp increase on most cars ?

So after an exhaust change and intake change (for what it's worth what's next ?

Get the inlet on the turbo enlarged ?

Want drivabilty more than chasing big bhp numbers !

[Simon_P]

On the standard exhaust the pipe is squashed where it goes over the prongeron. Probably for some good reason.

On the after market pipes it is not.

Can't believe an exhaust change takes it to 200 bhp though. Normally a 15-20 bhp increase on most cars ?

No, neither can I.

[lotusflasherman]

On the standard exhaust the pipe is squashed where it goes over the prongeron. Probably for some good reason.

On the after market pipes it is not.

Can't believe an exhaust change takes it to 200 bhp though. Normally a 15-20 bhp increase on most cars ?

No, neither can I.

Not sure about that...

In 2008 I asked Hanger 111 if Quicksilver could supply an exhaust for my SE. Think it was the first they made as the front pipe was tubular and was in noisy contact with the prongeron.
I took it off, heated it up with Oxy-Acet' and flattened it in the offending area and sent them photos with a comment that I'd have hoped theirs might have fitted for £418.30 !
I got a 'thanks for the feedback, try this one' reply and a new LO121 front pipe. Still not fitted it as mine's still working OK and I hadn't flattened it as much as they had for 'prongeron clearance'.
Here's a photo of their LO121...

lo121.jpg

I'd be interested to know if Karl's 200bhp Quicksilver exhaust has/had a similar flat section. My car already had a Manual Boost Control Valve, Lambda Sensor in turbo driving a LED Air/fuel ratio monitor so I could see I wasn't causing problems and a Bailey Recirculating Dump Valve. Quicksilver exhaust made quite a lot of extra difference but haven't a clue how much. If I used the BCV with it I got the 'wastegate needs porting' hiccup though.

[Simon_P]

Phil,

Agreed Quicksilver produce great exhausts very nicely made - I have one on another car.

The flattening of the OEM pipe is far more than that, and far more than necessary for clearance, and it is a smaller diameter to start with. The Piper and others that I have seen aren't squashed and must have 50%-100 more cross sectional area.

[lotusflasherman]

There is a massive step in the inlet tract around the injector housing. It looks like they shortened the length of it without changing the angle.
The top and bottom do not align so correcting it would require removal of material from the top of one casting at the top and the bottom of the other casting at the bottom. Do this and you have a dramatic increase in cross section area right by the injector.

Sounds like you've just got to do it. Be silly not to while it's there looking at you . These CNC machines can't beat a man with a grindstone in a drill...

[lotusflasherman]

Phil,

Agreed Quicksilver produce great exhausts very nicely made - I have one on another car.

The flattening of the OEM pipe is far more than that, and far more than necessary for clearance, and it is a smaller diameter to start with. The Piper and others that I have seen aren't squashed and must have 50%-100 more cross sectional area.

Simon,

Long time since I've seen an OEM pipe, cant remember what diameter they are.. My Quicksilver is 2" diam but my mod to their original tubular one didn't flatten it as severely as the one they supplied. When I've got time I'll copy the cross section of the flat section onto some graph-paper and count the little squares to see what the csa reduction really is.

The Elan with the Quicksilver is on SORN and was thinking of transferring it onto my 'daily drive' Elan. However, needed a new system for my Subaru Forester and went to Hayward & Scott in Basildon who supplied a stainless system with about 20bhp increase for less than a Subaru standard system. They said they could do custom M100 Elan if I left it for the day - at least it would fit properly! Once they'd done mine they'd have a pattern for other owners.

If anybody else wants to be the 'guinea pig' they're here... www.haywardandscott.com/gallery

[John_W]

When I've got time I'll copy the cross section of the flat section onto some graph-paper and count the little squares to see what the csa reduction really is.

See this thread: viewtopic.php?f=36&t=877&p=56498&hilit=Squish#p56498

Cross-sectional areas:
2" diameter (standard): 3.142 sq in
flattened section (standard): 2.5 sq in
2.25" diameter: 3.976 sq in.
2.5" diameter: 4.909 sq in.

The squish loses 20% of the cross-sectional area of the standard exhaust. Therefore a 2.25" exhaust effectively increases the area (compared to the squished pipe) by 60%.

John

[lotusflasherman]

When I've got time I'll copy the cross section of the flat section onto some graph-paper and count the little squares to see what the csa reduction really is.

See this thread: viewtopic.php?f=36&t=877&p=56498&hilit=Squish#p56498

Cross-sectional areas:
2" diameter (standard): 3.142 sq in
flattened section (standard): 2.5 sq in
2.25" diameter: 3.976 sq in.
2.5" diameter: 4.909 sq in.

The squish loses 20% of the cross-sectional area of the standard exhaust. Therefore a 2.25" exhaust effectively increases the area (compared to the squished pipe) by 60%.

John

Thanks for info John. Curiosity prompted me to find time...

An eminent engineer once said to me 'Listen politely to what other people say, but ignore it and start from Square One and work it out for yourself. If you agree with them good, if not you have a good foundation for an interesting discussion..."

Well, I measured my Quicksilver 2" pipe and where they have squashed it into a 'D' it has actually changed to 2.17" across the major diameter and 1.5" from the chord to the peak. I might have been able to do a theoretical maths calculation 5 decades ago but that would still be a theoretical calculation. Using 'graph paper technique' the squished 'D' shaped area is 62 'whole squares'; and the circular end of the pipe is 69 'whole squares'.

So surprisingly the flattened D section of that pipe actually has 62/69 or 90% of the csa of the circular section. The pipe I 'squished' myself is probably better than that too ..

How did you work out a 20% reduction?

[John_W]

Phil,
There wasn't a lot of science in my calculation. I took a card template of the cross section and, like you, counted graph paper squares. It was a long time ago and there will be a large error bar, but the pictures on the thread I referenced show a pretty severe squashing of the standard exhaust pipe.
John

[Simon_P]

Yes, the OE pipe is a lot flatter. I had the S2 cat and I was basing my engineers estimate of 50 to 100 % on that vs 2 1/4 and 2 1/2 in pipe. Nothing scientific just an estimate.

[lotusflasherman]

I was very surprised how little the csa had changed by the squashing into a 'D' section. My gut reaction was it would be much more so didn't think 20% would be far out but glad I measured it.
Still think if I get Hayward & Scott to build one I might ask them to squish a larger round section in that area so we get no throttling in the system at that point.

Looks like Quicksilver aren't interested in Elan systems as they haven't listed them for several years. Probably too few compared to the number of Elise/Exige variants on the road.

[Simon_P]

As it has a circular cross section a small squash has proportionaly small effect double the squash and the effect on csa is more than double (sure that you know this) the S2 cat pipe is as good as squashed in half. Hence my estimate and surmise that they were trying to influence more than just clearance with the restriction. Piper don't squash the pipe and there isn't a clearance issue. The only thing I have noticed is contact and a loud vibration for a few seconds after driving through a deep puddle with a hot exhaust. I haven't been able to trace the point of contact.

Someone on here once in the early days had an H&S exhaust.

[simonbuk]

So after an exhaust change and intake change (for what it's worth what's next ?

Get the inlet on the turbo enlarged ?

Want drivabilty more than chasing big bhp numbers !

If I just got it chipped would I suffer from boost creep with just a 2 1/4 pipe and KnN filter ?

[Artaban]

Simon,
I have the PNM/Cybox 2 1/4" exhaust and the K&N filter and I suffer from boost creep though its quite easy to control with the right foot. At some point I'll get the wastegate ported. You get to know when fuel cut off kicks in so you back off just before it does. I later fitted the mountain chip and I think fuel cut off came a little bit later but its still there.
Andy

[simonbuk]

Ok cheers, haven't had mine long and haven't driven it very hard yet. What sort of revs are you pulling when this sets it ?

I take it it just kind of dies on you if the fuel cuts off ?!

[Simon_P]

Save the money on the K&N. The engine already has more air than it can handle so it is almost pointless and you may as well have cleaner air and less engine wear.

If you want drivabiity you don't want boost creep.

Not sure why you want to change anything on the inlet side on a turbo engine with more air than it needs. Do you have a particular problem with lag?

[simonbuk]

Sorry didn't mean inlet on the turbo, meant wastegate on the turbo.

The KnN is already on the car - but I might put an air box back on and a recirculating BOV if it's going to quiet things down somewhat.