Straight Pipe thickness advice?

[G-Ammo]

Hey guys

I'm going for a full stainless steel straight pipe on 13th of may,
But I need some good advice on what thickness I need?

Its a 1KR-FE Engine... 3 cylindre 1.0 litre.

I think the original pipe is about 3 cm in diameter?

Should I have the new straight pipe with a 5cm (50mm) diameter?


Thanks

[Silver Streak]

G-ammo, Others can correct me if I'm wrong, but on an engine of that size I wouldn't go as big as 5cm. Keep in mind just going with that straight pipe is going to flow more that your stock system anyway, but going too large may actually hurt performance due to a lack of back pressure.

[1.5]

yea man 3cm is barely larger than 1 inch, i doubt its that tiny maybe 1.5" at the smallest and I still doubt that.

I went with 2.25" all the way from header back but I have the 1nz engine

[G-Ammo]

So how big should I go? maybe 3,5cm then? or 4?

[1.5]

i think 4 is still tiny that is only approx 1.6" how about 4.5-5?

[G-Ammo]

well that's what i've asked... 50mm (5cm) thickness... but I only have a 1.0 litre engine... isnt that too big ? original pipe is about 3 cm i think... maybe 4...

[Rigaud]

1.0L engine = 1.75" or 4cm max is fine. Their isn't enough air volume to require bigger and even at that size if it's all straight pipe without a catback you'll lose a lot of power.

[fnkngrv]

http://www.exhaustvideos.com/faq/exh...m-power-curve/



Check this out. According to these folks you should stick with stock diameter if you are making no other upgrades.

sent from my m-o-b-i-l-e

[Rigaud]

Originally Posted by fnkngrv

http://www.exhaustvideos.com/faq/exh...m-power-curve/



Check this out. According to these folks you should stick with stock diameter if you are making no other upgrades.

sent from my m-o-b-i-l-e

Exactly, you gain more from staying with stock size but going with mandrel bent pipes. Same with cold air intakes that usually only gives a faster throttle response but no real h.p. gains on small engines. Read alot of research and studies on it.

[G-Ammo]

Thanks guys! So when reading that table of the diameters... its better to stic with 3 cm / 3,5 cm in diameter or else i will lose alot of power.

I just emailed the performance shop about this.. I hope to get a positive answer this week.

[Rigaud]

Originally Posted by G-Ammo

Thanks guys! So when reading that table of the diameters... its better to stic with 3 cm / 3,5 cm in diameter or else i will lose alot of power.

I just emailed the performance shop about this.. I hope to get a positive answer this week.

[trunkout]

Me coming from "old school" modding.... The whole idea I was taught with "straight pipe" is to get exactly that... As much straight, unbent, pipe as you can replace from the cat back. Also... You want to have a section ABOUT the size of a muffler where the origin pipe sets inside (via weld) a slightly larger pipe. I've done this on several cars. Sounds angry. I've always loved this "glass pack without glass" sound!

[G-Ammo]

Ok so they replied:

they say 40mm should be the best because I still have enough airflow and stainless steel holds warmth better than the original. Plus i have enough back pressure cause of my cat and my header turbo on the nitto axle back exhaust.

I also asked them if they can put the exhaust pipes deeper into the chassis, because im so low to the ground, haha. Hope they don't mind doing that... :P

[1.5]

Originally Posted by Rigaud

Exactly, you gain more from staying with stock size but going with mandrel bent pipes. Same with cold air intakes that usually only gives a faster throttle response but no real h.p. gains on small engines. Read alot of research and studies on it.

how would the method of molding the metal effect performance?

[Rigaud]

look up mandrel bending. Pipes stay perfectly round in bends where as stock pipes are flattened and or rippled in the bends. Stock pipes have air flow restrictions due to that.