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[Michael]

Am I seeing right? Because those flanges have no holes!

Umm, yes - that is indeed a slight flaw in the design

[Mats]

Was this supplied with the engine? How are a couple of tube bends and a couple of half ready flanges "downpipes"?

[kevin]

Michael, The fuel rails that partner the red injectors (GTA spec and very last of the 3.0 34v spiders) have a deeper cap with a hexagonal nut on it as shown in my pic. Your rail DOES NOT have this. That is why the clip is bigger a it goes around the hexagonal nut. Your rails are more than likely of a 156 like the ones on my 3.7. which can use clips and injectors from the 164. This is not to confusing yet.
If you have 164 injectors which I think you said you ordered or have use them at this stage.
Strange you have bottom flanges with out holes. From my last six GTV's (some not on net) I have found that 50mm down pipes work best on 3.0 and 3.2. This can cross straight into your first box and then all the way using 63mm into last box.
Personally I have also found as on my race car the two banks been seperate from the heads to out side of car did not drop power but I actualy gained. This could be for a number of reasons ie shorter length of exhaust system. All the after market systems for our 3.2 GT's remain seperate from front to back.
Check page 12 on your thread. I know you cant do this but you can follow this principal. Mandrel bends will not make any difference but dont use those 63mm pipes for down pipes.
Pity I cant send you some Maps but they are not compatible with the MFI.

[Michael]

Was this supplied with the engine? How are a couple of tube bends and a couple of half ready flanges "downpipes"?

Yes - those parts were supplied with the engine. The exhaust is actually quite a logistics challenge ... had the downpipes been bolt-in (as promised) I could have cobbled up a temporary exhaust myself (linking the downpipes to my current system). This would have been enough to allow me to tune a bit, then drive the car around to various exhaust shops to get a few quotes and make a final selection. Now I have to pick just one, have the car moved there on a flat bed and hope for the best.

[Zamani]

Well you need a proper flange before you even bring it to a shop. No exhaust shop will have the proper flange. Once you get a proper flange and proper mandrel bends, then you're good to go.

[Michael]

Sounds good, It only does not start some time because your crank speed is to slow. Recheck cam belts. How much can you twist it on the long side. +- 60degrees. I know you set it with tools but it would be interesting to where it is now that it has been fired.

Yip - stll looks very good - though the belt did loosen up very slightly (I set it very slightly tight):

belt_tensioner.jpg (166.91 KiB) Viewed 6658 times

The piece of wire can be inserted through the holes in the housing and the push rod, and the 3mm drill bit can be inserted between the housing and the arm....

Damn - I should powder coat the tensioner - pretty ugly!

[kevin]

Michael, have got any friends , family etc here in SA. to pick up a set. I got spare flanges with holes as all mine were laser cut with holes. Stlii use two 50mm into first box under gearlever then 63mm straight to the back into last box. You will not go wrong. Its not something you can overthink.

[Michael]

Hi Kevin:

Thanks for the offer
I do still have some friends in SA - in PTA. I'd go for this in a second but I'd like to try using what I have first in the interests of saving time. Will try making a template and drilling out the flange today - fortunately, I have a reasonable drill press to use now!

Cheers,

[Michael]

I have ordered a replacement (Alfissimo stocks them ~$170) but in the interim, I was able to jury rig the sensor closer to the wheel and that got all the coils firing.

To confirm, installing a new CAS solved the issue.
One thing is that I could not find a cheaper replacement (it first seemed that a Cadillac Catera CAS would work...) - needed to order the original Bosch PN from Alfissimo - $170.
Thanks JJ

I ran the car some more yesterday - have it idling pretty well by adjusting the closing point of the butterfly valve. GoTech cannot control an idle valve which is unfortunate.

Thanks

[kevin]

Michael, did you check those flanges fit on those headers. Im still interested how much you can twist the cam belt with your hand on the long side if your covers are still off.
Im not sure which Gotech you have but as mentioned with time there are many upgraded models(since then) out just like the three haltechs I bought.(each came out with more channels and more GPO's ie idle control, fans, fuel pump, launch control etc) .
If you want the ultimate set up(for budget) try go for latest pro x with full sequential.I have noticed big power increase in the midrange with better consumption on my other 3.0. I really dont like advertising for anyone but where there is a noticeable gain I will mention it. Kinda like my Blackberry over the last two years-major upgrades !!

[Michael]

Hi Kevin:

I will remove the manifolds this weekend to check that the flanges fit. Actually, I see now that I need to weld a nut on the back of the manifold flange since there is no way to get a wrench in there to stop the nut spinning. This will also allow me to accurately drill the holes in the flange and try and find a gasket.

If I go for a twin exhaust set up (removing the spare wheel well) what diameter pipe should I use for each pipe? How about 57mm OD - which is like 53mm ID?

Also, does this sound good? I plan to use an X-Pipe near the front but still want to avoid having my car sound like a 3 cyclinder (Triumph motorcycle)

How much extra power comes from a twin pipe exhaust?
When I had my old 12v dyno'd, we did find 10 extra HP by replacing the rear exhaust with a straight through pipe so I tend to think that the new engine would also suffer worse if I use the same exhaust design there.

I will test the belt tension also this weekend...

[kevin]

Michael, to weld a nut on the manifold is a big NO NO unless the thread is stripped and then you dont even weld it, just hold the nut from the top. With the headers still on screw a stud in with your fingers. Make sure the stud is not to long otherwise it really difficult toget the down pipes off. Measure thickness of bottom flange plus washer plus nut and add 4mm for diameter of stud(stress curve up stud when tightening). Make sure you use 12mm nuts(socket size). When you tighten up the down pipes the stud will automatically tighten as the lip on exhaust nuts(copper) creates enough friction to turn it in. Does work - got five cars running like this for five years. I always use a flexible extention on ratched to tighten up.(150mm long)
No need to take manifolds off. Just place the undrilled flange over manifold(some one underneathe) and scribe it from top then drill to 9.5mm. I think 57mm is to big. I am getting results with 50mm on the 3.0 and 3.2. I got 57mm on the 3.7.
A well made 63mm last section from centre to over caliper will work well.
Check niclas racing 75 also 50mm first section.

[Michael]

Michael, to weld a nut on the manifold is a big NO NO unless the thread is stripped and then you dont even weld it, just hold the nut from the top. With the headers still on screw a stud in with your fingers.

These headers don't have tapped 8mm holes for studs - they are more like ~9mm so I would need to use bolts.
I do have some 8mm Helicoils - I could use those instead of welding the nuts on I guess.
I actually got the idea of welding nuts on the backs of the flanges from my 12v CSC headers.

I think 57mm is to big. I am getting results with 50mm on the 3.0 and 3.2. I got 57mm on the 3.7.

Do you use 50 mm Inner diameter or Outer Diameter pipe?
The flanges seem to be made for ~56mm OD pipe. I could get the Exhaust shop to taper the pipe gradually down to 50mm if that would result in a performance benefit.

flange_diameter.jpg (86.49 KiB) Viewed 6167 times

A well made 63mm last section from centre to over caliper will work well.
Check niclas racing 75 also 50mm first section.

Yes - but will a thinner diameter, dual system work better?

[Zamani]

Mike,

About the flange, I think it's just an honest mistake by the supplier. I'm sure you can ask JJ for a set with holes. That would really make things simpler.

BTW, the downpipes Larry supplied me are nice stainless 2.25" OD with 3 bolt flanges (TIG welded!!!)

[kevin]

Michael, are they no threads in the manifold flange ? If not you have no choice then you might as well take it out and just weld a nut on. Please PM with your adress. What size is the outlet of the header. Should have an insert welded into it to prevent gases blow by. Like ones below.