project stiffy, free flowing custom downpipe.

[stevo]

WOO HOO!!
the first one is ready. its a bit rough but its just to test fit in my car for size and a dyno run.

pics to follow.

[Ian_W]

Nice one, will be very interested to see the dyno results how much extra BHP are you hoping for?

[stevo]

ok, small technical problem......

as i was photographing them i noticed that the pre-cat chamber was bolted on the wrong way round. my fault i shouldn't have left it with him in 2 bits

should be a quick fix to turn the port round but here is a sneak preview anyway. remember that this is a rough prototype to measure clearances and bhp and the finished downpipes will be a lot nicer.

[Andrew_Ennis]

Stevo,
This looks great, i have had a precat housing made with a 2 1/2" outlet, so it will be interesting to see how much extra a stiffy makes.
i think it would be very important to see if the bracket between the engine and the precat housing can be retained so the bottom of the new pipe is supported.
I would imagine either a plate of sort welded to the new pipe to line up with the holes on the engine or using the original bracket and threaded tube welded to the stiffy pipe. The reason for this is the pipe is quite long and without this bracket the loads from the exhaust during engine movement will be all taken be the turbo housing, transfered to the exhaust manifold and the alloy head. These loads will be large during hard acceleration and power reversals where the engine rocks on the mounts. In engines where the bottom of the exhaust is not braced cracked manifold are very common was the comment i got from my exhaust builder when i got the front section made.

[stevo]

mmmmmm, interesting, will need to look in to that.

[John_W]

In engines where the bottom of the exhaust is not braced cracked manifold are very common was the comment i got from my exhaust builder when i got the front section made.

I can confirm Andrew's comment based on experience with Lotus 907 engines fitted to Jensen Healeys. These were welded tubular manifolds (unsupported except for the studs into the head at the gasket) and used to crack regularly and cost a lot to replace until a specialist re-engineered them. (I'm not sure if Esprits / Excels etc are prone to manifold cracking.)

If such problems occur with an installation where both engine and exhaust are longitudinally-mounted, I imagine the forces involved at the head/manifiold interface for our installation (where the exhaust runs at right angles to the engine) would be much greater.

Worth considering.

John

[stevo]

the stiffy is in getting fixed and thanx to gazza for the pic of his(yes gazza sent me a pic of his proud stiffy) and the other above imput. i will have a braket mounted just like gazza's and it will be ready to show off at callander.

[Gazza]

Stevo,
I haven't got a stiffy (exhaust), that was a picture I had of someone else's stiffy (exhaust), made by Haywood and Scott in Basildon.Just thought it might help you.
I only had the exhaust from the pre-cat back, so I am watching your stiffy progress (exhaust). What diameter will it be at the pre-cat end?

[stevo]

cheers gazza, it will be 2.5.

[Dico]

it will be ready to show off at callander.

Stevo, are you going to be showing Steff your two and a half inch stiffy at Callander?

[stevo]

im not going to rise to that one :gray:

[discovery]

Excuse my ignorance , but will i benefit having one of these ? pros and cons etc.
Mine is a standard se .

[stevo]

no problem disco, the idea is that i am trying to make the exhaust system more efficiant to increase power and torque. most people who have bigger bore stainless exhausts fitted(me included) have had theres replaced from the down pipe back because the down pipe is an odd shape and expensive make. my plan is to have these pipes made as a direct replacement for the old cast downpipe for people to fit ahead of the big bore systems.

if you want one i can put you on the list but it would work best if fitted with a full system.

[woody]

Hi Stevo,
Your stiffy also replaces the pre-cat as well doesn't it.
Woody

[stevo]

it does indeed my friend, i replaces the whole lot inc some of the heat sheilds.

come to think of it there will be a nice little weight saving too.

[Doug]

the pipe pictured above is a replacement from the turbo outlet itself to the downpipe junction--this is a replacement for the parts not usually replaced

it will not bolt onto a stock exhaust so you would have to fit this onto a custom system at the end of this pipe onward

this mod would be good to add a bit more flow to cars with already modded exhausts for those who want to go the extra yard

[Sy V]

A word of caution.

I have the expensive H&S version of Stevo's stiffy and it's blowing at the turbo end. I hope to tackle the problem today. It may be the gasket, it (the stiffy) may just have worked its way loose. These two are easily remedied however, given the fact that I also have a sports clutch fitted and (while it was bedding in) was getting some quite violent engine judder on take off I wonder if I might encounter some more sinister problems when I address the situation...

Let's hope not.

[chrisP]

Let us know what the problem was Sy, as I have one of the H&S creations and it would be good to know if its potentially going to cause problems

Chris

[Sy V]

OK, I haven't been able to get round to it yet though...hopefully this w/e.

[stevo]

yeah keep us posted.