Confusing Exhaust Sizes

[Manuel Kasko]

Sorry guys, picked her up lastnight and have been busy since. RP were under the pump and down on employees, they have so many cars down there to finish lol.

R33 GTS-T (~150,000km)

Apexi pod filter

Yellow Jacket coil packs

3 inch turbo back

Blitz CS FMIC

Z32 AFM

Bosch 040

Nismo 555cc

Power FC + EBC kit

HG SS1PU custom (Nissan comp housing instead of ATR43)

258.6rwkw @ 16psi on Shell V-Power (98)

Second line is a slightly safer tune with some pulled timing and more fuel, making 252.4rwkw.

[XKLABA]

Going from 3" down to 2.5" is not a good thing and given how the boost trails off about 3 psi I'd say your right and it is a restriction of some sort

I always say fix what you know is not right before something that might not be right, remove the 2.5" section and make it all 3" and see if that helps then go from there

[Birds]

Mani, run 3" all the way from turbo back. All you can do is eliminate one variable at a time, but you'll spend a lot of money chasing those few extra kw. For all you know your engine could have less than ideal compression and you'll never fix that without a bottom end.

There's nothing trick about my setup, I just spent good money on the components that affect power/reliability and probably got lucky with the condition of my engine. It made 170rwkw on standard boost, standard turbo, with just the exhaust and front mount.

While we're here, the exhaust was $500...custom mild steel 3" mandrel bent w/X-Force cat. Idiots go and spend $1500 on a big brand, sounds-like-farting stainless system, thinking that the 3 inch diameter of one will flow better than the 3 inch of another. It's not a complicated science.

[Manuel Kasko]

Cheers for all the information guys.

I was thinking the same thing with just make the system a consistant size all the way through.

From the figures I provided.

Is my dump pipe actually 3inch or 3.5?

I measured it across the face and it came to exactly 8.5cm which measures 3.3inches

[AngryRB]

Cheers for all the information guys.

I was thinking the same thing with just make the system a consistant size all the way through.

From the figures I provided.

Is my dump pipe actually 3inch or 3.5?

I measured it across the face and it came to exactly 8.5cm which measures 3.3inches

why dont you also crank up some boost with a EBC, make it 19psi spike and hold 18.. then fry some tyres

Edited February 14, 2013 by AngryRBGTX

[Manuel Kasko]

why dont you also crank up some boost with a EBC, make it 19psi spike and hold 18.. then fry some tyres

It's running 20psi and bleeding to about 16psi

If it could hold the 20 then that would be great but I will work on that soon

[AngryRB]

Actually , in comparison to the others there not much difference, everyones around 250-260kw, your matching hypergears graph most of the way, it probably nothing to do with exhaust restriction, more about boost and engine condition and tune/timing etc, even different dyno ? thats looking pretty good for only 16psi.. id just replace cat and get it holding 18psi, could be 20kw's or more left in it

Edited February 14, 2013 by AngryRBGTX

[Manuel Kasko]

Then water meth to make sure it's not temp related!

Got the water meth kit sitting at home

[AngryRB]

you've actually got more than birds at 110 and 130km's, so its looking good, with water meth and boost you might make it close to 290-300

Edited February 14, 2013 by AngryRBGTX

[Joshbigt62r]

I would replace the cat with atleast a 3" 100 cell cat. Stepping down to 2.5" cat is not good for flow. And if your running a gutted caf on the street be prepared for some trouble with EPA ect.

Cheers Josh.

[Stevoss]

http://justjap.com/store/home.php?cat=275

[ARTZ]

you've

actually got more than birds at 110 and 130km's, so its looking good,

with water meth and boost you might make it close to 290-300

yeah a mid range spike is often good for some extra kws...

if you have a water meth kit put it on and you cat would be best to be the same size as your exhaust.... but other than that don't worry cause your cars fine Mani...5-10kws can always be just a dyno variance anyway..just go drive the thing..I wanna see you do a 1.10 at wakie before you come back here moaning again..

[Hanaldo]

Yeh I wouldn't be too concerned about 5-10kw dude. That's nothing. Go take it to the drags and see what trap speed you can get (I don't think the results you got from the airfield are very accurate, otherwise you definitely have nothing to worry about!).

If you get anything close to my 108mph, then come back and we can cry together

[Manuel Kasko]

Yeh I wouldn't be too concerned about 5-10kw dude. That's nothing. Go take it to the drags and see what trap speed you can get (I don't think the results you got from the airfield are very accurate, otherwise you definitely have nothing to worry about!).

If you get anything close to my 108mph, then come back and we can cry together

Haha will do!

Got myself a 3.5 inch Venom 100 cell just to be safe.

This will come in handy anyways when I put the water meth kit in.

Measured my exhaust again and the inside of the dump = 3.5 inch

I also took the cat off and measured after it (between cat & muffler) = 3.5 inch

So this should be a perfect size.

Do people normally weld it straight to the original exhaust?

[ARTZ]

Do people normally weld it straight to the original exhaust?

no put flanges on it so you can bolt/unbolt it...my exhaust is all in one piece and its a pain in the ass when you have to work on it cause you cant drop it in sections..which usually results in me standing there holding it for ages while scott welds shit to it...not fun

[scotty nm35]

But flanges cost money.

[ARTZ]

so does building your exhaust all wrong and having to do it again...

[SiR_RB]

Can wind some more preload on the wastegate actuator arm to hold boost more steadily?

[Hanaldo]

Yeh get flanges put on it man. My exhaust guy gets his mild steel 3" flanges for $6 or something. The number of times I've taken my exhaust off, I would've set the car on fire if the exhaust didn't come off in sections.

[wedge_r34gtr]

Yeh get flanges put on it man. My exhaust guy gets his mild steel 3" flanges for $6 or something. The number of times I've taken my exhaust off, I would've set the car on fire if the exhaust didn't come off in sections.

this! or you can get 3" SS v-band clamps for around $30