help with exhaust please

[Hound Dog]

i brough an exhaust back box and mid pipe all in one from someone on here , i took the car to the garage to have it fitted and not being rx7 garage they have asked what happens to 2 pipes on mide box as i dont have a mid box anymore ? any help would be great ie do pipe just get blanked ? many thanks jay

[20B_boy]

One is the pipe that comes from the air pump in the engine bay. The other is I think the temp sensor for the cat. I dont think it really matters what u do with them, although u may perhaps have problems with the cat light on the dash if its not connected to nay thing??

The air pump pipe you can just tuck out of the way. You may as well get rid of your air pump and save about 10lbs of weight too as its redundant without a cat to pump into.

What ECU r u running btw mate? it sounds as though u have a lot of exhaust mods - hopefully u arent on the standard ecu?

[Hound Dog]

i am on normal ecu atm
down pipe is standard just no cat on mid and a big arse can  on rear

[scooby_si]

The usual advice is to upgrade ECU before going the way of the decat http://www.smileycentral.com/?partner=ZSzeb008\' target=\'_blank\'>http://smileys.smileycentral.com/cat/8/8_1_29.gif\' border=0>so i\'d defo look at doing that sharpish before anything goes awry......
Si (devils advocate http://www.smileycentral.com/?partner=ZSzeb008\' target=\'_blank\'>http://smileys.smileycentral.com/cat/347.gif\' border=0>)

[20B_boy]

To be honest the Jap market down pipes without the pre-cat are pretty good. Be careful mate, start by getting a boost gauge and seeing what numbers your system is making. Ideally get it to some one with a WBo2 sensor so they can confirm you arent running lean enough to cause damage.

Start saving for an ECU and fuel system upgrades if you\'re thinking of doing much else to the car...

[Hound Dog]

was told by the person who supplied it that i would be boarder line but not to run it too long with out upgrading ecu . anyone doing a good deal on apexi ecu and commander ?

[20B_boy]

Ross/Dragon probably has a used Power FC in stock, Geff/RE:Worx will sell u a new one (usually from stock) or may be a used one, he has them periodically...

Check the vendors section for others.

[Hound Dog]

i already have a boost gauge i take it im ok as long as it doesnt go over 0.9 ?
exhaust being fitted tomorrow induction kit too so will see what happens then i guess
thanks for all the info

[20B_boy]

0.9 max boost *should* be ok, plenty would say its still a bit dicey though...

You also want to watch what the needle does during the transition between turbos; look for spiking as the second turbo joins in.

[bobster]

Whats the best way to control/subdue this spiking?
I get spiking at transition but it never gets over 10psi.

Also I need a new mid-pipe since the current one has the flanges fitted at 45 degree angles, and I cant fit my cat back.

[Robertio]

Originally posted by 20B_boy
0.9 max boost *should* be ok, plenty would say its still a bit dicey though...

You also want to watch what the needle does during the transition between turbos; look for spiking as the second turbo joins in.

You\'re not wrong there that\'s got to be close to having to roll double sixes every time you floor it.

[20B_boy]

I agree mate; I mustve been rolling several sets of double sixs for 12 months how my car was running Just hope my next motor is as understanding!!

[Hound Dog]

my car standard was running near 0.9 max boost , what should it be then ?

[Robertio]

Closer to 0.7  IIRC std early cars were 10-8-10psi

Ignoring fueling etc. I wouldn\'t be happy running the stock intercooler at 0.9, but that\'s a personal opinion based on the temps mine was running at with less boost.


Rich, I think it\'s safe to say the car is getting its own back for the abuse now :p

Bob, you know that getting a proper midpipe and your new backbox on would make sense.  It may be that that alone will sort out your boost issue.