Will 2" exhaust will be sufficient for the 4AGE 20V Blacktop

[onnaj]

Hello,

I own a 1998 Celica ST. About 10k km ago i completely rebuild and swapped a 4AGE 20V Blacktop. The engine is completely stock and the only mod i have is an Apexi cone filter and when i grinded the valves i polished the exhaust chambers. That are the only mods and i'm not planning to do much more mods in the future. (maybe i want to achieve 175-180 hp max)

I'm now still using my stock 7AFE downpipe (1.5" OD ), my stock 7AFE catalytic converter (2.5"), stock centre exhaust (1.7") and stock rear muffler (1.6"). These are all outside diameters. With this setup i managed to get 148 crank hp and 153 nm torque and that was only 2800 km after the rebuild. The car feels a lot smoother now it has done 10.000 km.

My plan is to grab an OEM AE111 Levin header (2.25"), keep my stock catalytic converter, a custom 2" centre section and an OEM Toyota Celica 3SGE 2.0 rear muffler (also 2" outside diameter).

Would that setup be sufficient for the blacktop the breath well and keep torque available?

Thanks!

[dnegative]

Depends, I think 2 1/4 is a pretty good size for 4A's working hard with revs.
Big enough to minimise back pressure but small enough to have good exhaust gas velocity.

[onnaj]

Problem is 2.25" mufflers are not readily avalaible over here. Mostly it's either 2" or 2.5". I think 2.5" is a bit too big and i don't want to much noise from the exhaust. I just wanna hear the intake

I know the stock 3SGE 2.0 has 2" from the front till the back. It produces more horsepower (175hp), is a bigger engine (2.0 vs 1.6) but it's max rpm is 7200 vs 8200 for the BT. So would that 2" be sufficient for the BT??

[jondee86]

I'd go with the 2" exhaust. It will help the engine maintain
torque in the normal driving range. A larger pipe would only
be helpful at maximum engine speed.

Cheers... jondee86

[onnaj]

I'd go with the 2" exhaust. It will help the engine maintain
torque in the normal driving range. A larger pipe would only
be helpful at maximum engine speed.

Cheers... jondee86

The 2" OD (i think it's always OD) will be 1.85" ID, but that's enough you think?
Ofcourse now and then i will be accelerating to 8000+ RPM

thanks!

[Indelible]

this may help i found this usefull in the past

http://www.exhaustvideos.com/faq/how...pipe-diameter/

[old_mr2]

So long as its free flowing and your muffler is straight through, Id go 2.0".

2.5 will drone/rasp and I doubt you would see any benefit to hp/tq.

[jondee86]

The 2" OD (i think it's always OD) will be 1.85" ID, but that's enough you think? Of course now and then i will be accelerating to 8000+ RPM

If the tube was available, I would say use 2.25" diameter. But since the choice is between 2.0" and 2.5" I think that the 2.0" is preferable. It will be a nice improvement over the existing system. A 2.5" system will only give a small advantage at the highest rpm, but it will reduce the driveability of the car at the rpm's used during everyday driving.

Cheers... jondee86

[onnaj]

I decided to go for 2". 2.25" is like i told almost not available over here and 2.5" is too big imo.

I've also checked this website: http://www.exhaustvideos.com/faq/how...pipe-diameter/ (thanks for the tip!) and asked him a question about what he think is a good size. Besides that i did find out that the Honda Integra R uses only 2.1" piping (that on some places is even only 1.9") and produces 190 hp @7900 rpm and can rev even higher (8500 rpm vs 8200 rpm)

So my setup will be (all in outside diameters):
Stock 4AGE 20V header: 1.75 inch i believe
Stock 4AGE 20V downpipe: 2.25 inch
Stock 7AFE Catalytic converter: 2.5 inch
Custom centre section: 2.0 inch with quality Simons chambered muffler (i don't want too much noise or droning)
Stock Celica 2.0 3SGE rear section: 2" with chambered muffler

Does anyone know how much a stock 20V blacktop head will flow? I thought it's about 180 cfm, but can't find the exact number.

[marvis]

I would go 2.5 for sure. 2" will be too small for what you are wanting to do later on, sure it might be ok now, well maybe a little restrictive.

Plenty of info around on the internet

[BLK_20v]

2 1/4" is a good size for 20v.

[LittleRedSpirit]

Ive had a few 20vs and tried 2 and 2.25 inch.

I prefer the 2.25 inch, however with the 2 inch I was able to initiate and slide it better, had a better hit in the mid revs to get you going. I think my car made 100hp by 6000 revs, but fell flat after that with a 2 inch. If you want to hit the peak numbers you speak of you will most likely need poncams and a 2.25, otherwise while driveable it wont work up in the revs and get anything like 175hp.

[onnaj]

I'm not looking for the most peak power, but driveability for daily rides is the most important. I'm going for a 2" catback with the stock 20V header and 2.5" catalytic converter.

I'll update later how it worked out