Hayward & Scott downpipe

My car was used many years ago by Hayward & Scott to build the first 3" downpipe for the 20vt

I've used the car very hard ever since and the pipe has been faultless (apart from wearing through part of the flexi where it rubbed on the undertray, but that's hardly the downpipe's fault)

However, when Barbz delivered my freshly-ported cylinder head, he commented that the downpipe would be holding back my power, as it wasn't a true 3". Sure enough, on inspection, it's pretty obvious that it's tapering down to about 2.5" - 2.75" for the initial bend, then up to 3"

Its clearly not a massive restriction, otherwise I wouldn't have produced the power I've got, but Paul at Motormech is going to have a go at fabricating a true 3" downpipe, just to see if it can be done within the (very) tight confines of the Coupe engine bay. He's got hold of a 5-stud flange and a 3" downpipe from another car - this also has a very tight bend straight out of the turbo - he may be able to cut 'n' shut the pipe to fit the 20vt

I've seen the MIJ downpipes, but I have to say I'm not particularly impressed with the sharp angle that has been fabricated into the elbow.

Anyone got any suggestions or piccies?

nigel nigel you havent seen joes FCSS page have you with the true 3.5" down pipe on it and the external wastgate plumbed in.

its a work of art

I have a full 3.5" system including downpipe, but the space is so tight, the very first bend from the turbo is 3" widening to 3.5".

How did you manage to fit a full 3.5" bend in there?

from what i remember the oilcooler pipes where braided to make space

Can't find it...

http://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Number=1360621#Post1360621

Go to photos and look for it Nigel!!

Clicky Here you go Nigel

im sure it tappers down at the end to match up to the 3" that was already made for the car

By making major adaptions, but once done there's plenty of clearance.

http://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Number=1388098#Post1388098

Give me a bell Nigel, impressive gains on spool up.

Just a thought....

Why down we extend the manifold downwards by say three inches, thus lowering the turbo) so that we can get a straighter exit from the turbo?

Should be possible with a pair of flanges and a short length of stainless tube

Would it cause more lag?

I looked at this but the turbo fails on the block casting for the balance shaft, moving it forward fouls the rad so larger turbos are limited for there position.

Makes sense - just wondered why it hadn't been tried before

Shame we can't move it a couple of inches to the nearside of the car, but I guess that would require an entire manifold - not worth it just to open out the initial bend

Paul has an idea he's going to look at next week - watch this space....

Nigel, I did mention to you that the Hayward downpipe wasn't a true 3" when you first had it done many moons ago. I don't know why they did that really, just a bit lazy perhaps, as it's not that hard to make a full 3" system without any modifications to the standard setup.



The 3.5" is a different kettle of fish, but there is room to be found.

Anyway, it is certainly worth doing, we need to see every last bit from that turbo of yours.

Just a thought but doesn't Paul do exhausts?
If so the components can be bought cheap and then its just the welding.
A downpipe won't cost you more than £70 in materials.

Agreed - I'm sure it has quite a bit more to give with the right supporting mods, especially in the areas of spoolup and mid-range

John - yes, Paul also runs a Longlife franchise, so we have access to everything we need to make a one-off. My exhaust from the downpipe back is a one-off 3" system built by Paul

The hardest bit is the first foot or so - getting cleanly out of the turbo and turning sharply downwards, without restricting flow or touching the oil cooler pipes.

I'm just searching for some heat-wrap - I think I'm going to need it this time

Yeah the first few inches is difficult.
I made 1 inch segments and welded them on that way.
Made it also easier to tig weld them as tig is less forgiving if you have gaps.

The first foot had around 9 segments on mine.


Made life easier to Tac them and then machine the weld off from the inside to promote the flow.
Took me 4 days to make mine,but around 6 hours to make the downpipe.

But I had the joys of trying to squeeze a 4" exhaust in so won't take you as long.

Great satisfaction to see it built at the end.
And further to that saving yourself a few quid for a better job is always worth it.
Paul will love doing that

have you got any pics of yours JBT would be good to see in comparison with the other's on the market, i was thinking of lobster backing mine and i still think it will be the best option.

Copyrighted I'm afraid.
Only Barbz,Biggenz's and crazylegs have seen it
And it's covered in heat wrap .
2mm clearance each side of the sump.

Front section upto the handbrake cables looks a work of art.
Chocolate orange comes to mind .
The back half is scruffy as I lashed it together as I was getting peed off with welding and fabrication on the 4th day and needed it done for mapping.
My face was burned,my hands were torn and my head ached.

Trying to et 4"components was no mean feat.
Had to use truck exhaust.

But as Ed China would say.
Probably saved myself £600 in expensive garage costs.

But....you had a nice tan.

Yeah only problem is it started peeling the next day which made me look like i had some sort if skin disease.

Never a good look.

Who, JBT? You're not wrong lol

Dude I looked like Mattm

Your taking a pasting tonight jbt.
Everyone is having a dig. Cough cough (power envy) cough.

I dish it out enough,so its due returned.

As proctard says,if you want to give then you must be prepared to receive.

At least that's what his man friend says

It's lukcy i read the whole of JBT's post otherwise i might have gotten the wrong idea

copyright

Hello Nigel
Have you thought about going for Teflon coating on the inside of the downpipe once completed?
This will help with the temperature issue and might save all the pipe wrap.
It was an option offered to me years ago on a Caterham to move the heat out of the engine bay (to get around a vaporisation issue with carbs).

Roy

Hi Roy

I had looked at ceramic coating to the outside (I assume cheaper than coating the inside?)

Zircotec and Woof do it, but it costs about the same as the downpipe!

I'm not overly bothered about using pipe wrap - its mainly to stop heat soak into the oil cooler pipes, so I may just wrap the oil pipes instead

I wrapped both my pipes individually on the oil cooler as Didnt want to retain the heat after cooling.
Wrap the pipe too which might cover up some quick welds .
With heat wrap make sure you have no oil leaks or it goes up like petrol.

Well there is a name that is certainly a blast from the past

You may be better off using something like This Nigel?
Or this one with an even higher rating.

Not sure Roy ever went away, just went quiet for a bit (presumably spent all of his time driving his Sprinty - now has an epic 285,000 miles on it)

Well, at an epic 5.6 posts per year, you're probably right.

I lost my old login when the site did its thing years ago...... And did not feel like saying much since.

Hello Begbie, long time no speak

I do see Nigel from time to time as he now has a bed and desk set up at motormech

Roy

Lovely downpipes chaps.

You should see the elbow in my rs6 down pipes - awful!

Things are moving along slowly...

Paul's downpipe idea didn't work (using a 5-stud flange downpipe from an Impreza) - flange shape was different

So - I've bought a stainless T28 flange of the correct shape, and Paul is going to have a go at fabricating a true 3" elbow

I've also bought some good-quality heat wrap for the downpipe and some reflective heat-resistant tape for the oil cooler pipes

Head is now built and ready to go on next week, so there's light at the end of the tunnel

the sharp angle was only on the version that mated to the standard 2.25" v-band, the transition/alignment between 2.25-3in was very tight in the space allowed.



The 5 stud version was different, and a true 3in elbow. it used a 5 stud to 3in v-band adaptor, and then 3in all the way down to the cat.




I too have wrapped the DP, and foiled the oil cooler pipes.



Hope that helps

Ninja

Is there any place that will do an off the shelf 3" downpipe or are they pretty much only ever available custom made on the car?

W

It's better to get it custom made mate that way it's bespoke to your car you only have to have the down pipe slightly out by a fraction and you have now brought a big paper weight

full 3' downpipe.

Ben

Mine was full 3" from H+S

Same here, i just asked for a full 3' downpipe, simple.

Ben

I think this is the point guys. You ask for a full 3", and don't get it. I've seen a few in the flesh now and they don't look like much. Nasty, messy welding and not true 3" at the most important area.

I asked for and paid for a 3" downpipe, but I didn't get one.....

I'm guessing it was nearer 2.5" around the sharpest part of the bend.

Still, the H&S pipe is no more- Paul hacked off the flange to use as a starting point for a custom 3" downpipe - it's about 50% built now and just needs a little bit of tidying internally

With a bit of luck and a cancellation or two, the rest of the pipe can be built and the remainder of the car put together.

I've also had the rear subframe removed to fit PU bushes, I've had a new 24mm rear ARB fitted, new rear brake compensator, new front discs and pads and new front wishbones. Should feel nice and tight when it's back on the road (hoping to have it mapped on Friday)

wouldnt it been cheaper to sell the old DP and start a fresh?

it will be good to see yours after the mapping and what improvements are making.

could see Nigel well into the 500bhp club!!!

he will see you there then marco

hows the diff going?

HA i would love to be in that club!
thats the deep pocket club in my eyes

the diff, well after mapping i will share my experience with you all!

for now, all i will say is... A Quaife is the way forward for any one wanting to take the coupe to the next level.

im surpised the small number of people with them fitted are not letting the rest of the forum know how bloody amazing these things really are!!!!!!
but they know...
they know

Oh yes - we know....

I doubt if I'll be into the 500bhp club - I specced a meatier mid-range when Barbz was porting the head. It's all very well having big-number peak power, but if it makes the car less drivable then its pointless. My car was already as laggy as I was prepared to accept, so when a new head was needed, I took the opportunity to try to lower the spoolup point.

Yes, the bigger downpipe and bigger injectors will help increase the peak power, but if I came back from Leighton's with the same 450-ish bhp and a decent increase in the midrange, I'd be happy. Of course, if Leighton manages to find some extra ponies at the top end, I'm not going to tell him to throw them away....

well i havent driven a coupe with one in yet but ive still booked myself in next year while im away so should be testing it when i get back. if anyone isnt done a write up by then il do it.

Did Nigel get mapped today??

Not too sure...

Would text him but its far to late...

Nigel... Feel free to let us know the outcome!!!

Outcome was that this week didn't go as planned - car is still not back together - subframe is still on the floor and the downpipe isn't finished yet (I spent a noisy couple of hours smoothing off the inside on the pipe on Wednesday)

Paul's diary suddenly got very busy, so he just didn't have the time this week

However, he's cleared the diary for next Friday, so hopefully it will be finished by next weekend - I'll have to book time with Leighton for sometime the week after

Update

I got the car back last Saturday and I've spent the week running it in. Paul changed the oil and filter today, which has allowed me to explore a bit more of the performance.

For the whole of last week, I was running no more than half a bar and 4,000rpm max, so it was difficult to get much of a feel for the car. However, it was obvious that boost is coming in earlier - I'm seeing positive boost well before 2,000rpm

Now the oil and filter has been changed (and the sump plug helicoiled - sorry Paul), I've opened it up a bit more. I'm still running base boost (about 0.8 - 0.9 bar) but I've upped the revs to about 6k. The difference is now very noticeable - there is much more of a five-pot growl to the exhaust note and its absolutely flying. It really pulls hard from quite low down and just gets stronger as the revs rise. I have a feeling it will keep pulling all the way to the redline.

Handling is much improved (again). I've always said that the uprated rear ARB was the single biggest handling improvement I've made to the car - going up another 1mm to 24mm has made the car even less prone to understeer (although because of the new wishbones, the tracking was miles out - 4mm toe-out - steering was rather 'pointy'). It's now very planted, but with a very positive turn-in as well - just what I'm after.

The PU rear subframe bushes are also noticeable - in two ways. I can feel the rear end is now under control - it just follows the front and never feels like its doing its own thing - exactly what I was after. However, I have to report that road noise is also up a bit - unavoidable, I guess and it makes me very glad I didn't go for solid bushes.

So - another week of taking it relatively easy, then a remap, then we'll see what Barbz's new headwork has given me. Can't wait....

Sounds good, look forward to hearing how everything goes, good luck.

P.S Ive always heard people talking about when the get positive boost and anything below 2k revs is very good, although I must say on my car I get positive boost literally from take off at around just 1,200 rpm.

Yes.. Looking good by the sound of things Nigel...
Should make good power to go with the handling improvements..

Oops - misfire at 6k rpm at base boost - hoping its just down to old plugs - new BKR8EIX ordered - glad I found it before I have the car to Leighton next Monday

unless its a coil pack breaking down nigel.

any updates always a good read