mx5cartalk.com

I'm getting a 2.5 inch catback system made on Thursday, the original quote I got was for a press bent system. Is there a huge difference in flow on a turbo car compared to a mandrel bent system ($300 more)?

I know that press bends reduce the cross-sectional area, but hot gas flows better than a cooler gas, so is the difference going to be less noticable than if it was a NA engine?

I guess I could always get them to step it up a size to 2.75 or 3 inch?

Cheers

press bend is fine, a press bend 3" would flow more then a mandrel 2.5", mx5 exhausts dont have a lot of bends so go a 2.5" & save your money for another gift ;)

I went with a press bent mild steel 2.5 system with a highflow cat and a straight-through muffler. Sounds good, not too loud, I'm happy for $660

Had my first drive of the 5 with boost, it seems to make a lot of whooshing noises but not a huge amount of forward progress. No push in the back anyway.

Have you got a leak somewhere?

Thats what I was thinking, but it wasn't blowing heaps of fuel out the exhaust... and it just occurred to me that I no longer have an airflow meter so of course it wouldnt blow unburnt fuel out..... Maybe I do have a leak.

Does the fifth injector on a AVO kit have to be removed and a plate fitted over if you arent using it, or can you just leave it in place? I'm not sure if maybe it could be leaking out there, or if I have to go hunting for something else. I'm sure that all the cooler piping was done up tight

If it were me, I'd get rid of it and put a blanking plate. Attack every clamp with a screw driver/socket, just to be sure.

yeah i put a blanking plate on mine.

i agree with daz, sounds like you may have a leak somewhere.

I did all the hoseclamps, they're all pretty bloody tight. I'm going to change to using those other clamps, is it t-bolt clamps?

I'll check the cooler piping clamps next time I'm where the car is though

the first place i would check is the manifold. the avo mani is a bit of a pita to fit and i had an exhaust leak on mine when i first fitted it coz i didn't get one of the bottom bolts done up tight enough.

another thing i had an issue with was the intercooler. mine was the older style avo intercooler so i'm not sure if this is relevant to you, but there was a bracket that bolts on to the intercooler, in the end tank on the driver's side. there is a threaded hole for this bracket and unless you have a bolt in there, well all your boost pressure is just gonna blow out that hole (as i discovered, when the bolt came loose). but yeah i'm not sure if this hole exists on the newer avo intercoolers...

Aaaaaaagh, not the manifold That thing is a complete pain in the arse. I'll remember to try taking the passenger side wheel off first though this time, would have been far easier last time if I'd thought of that I think

I dont think my cooler had any other fittings, will check though

my leaky manifold was quickly diagnosed by a local exhaust shop, using a probe. and fixed easilly by one of the local ricer tuning shop mechanics after my initial attempts failed.

also, don't forget the blanking plate

Did you guys use sealant around the blanking plate, if so, what type?


So it was just one of the nuts on the manifold studs not being tight enough?

Re the hose clamps. When I first installed my setup some of the hoses popped off under boost. I replaced every clamp with one of these, and have not had a problem since.



http://www.breezeclamps.com/ct.htm

They are same design as used on the SP. Not cheap at between $9.00 and $13.00 each....but boy do they hold those hoses in place.

I was pointed to a distributer in Melb that is a truck specialist, so they had a big range of clamps. Also just found some on flea-bay -->> http://stores.shop.ebay.com.au/PartsSys ... QQ_armrsZ1

Re the exhaust mainifold, I used an extra OEM gasket when fitting mine. I read this suggestion on either the big forum, or the miataturbo.net forum.

Good Luck.

J

Adam_NAclubman wrote:Did you guys use sealant around the blanking plate, if so, what type?


So it was just one of the nuts on the manifold studs not being tight enough?

some sort of asket sealant is on the plate is probably a good idea.

yeah the bottom middle 2 nuts on mine were where the problem was. just not tight enough.