What would be a better exhaust?

[fjs3]

Hi all, new guy from the Philippines here. Just wanted to have some advice on my vehicle's exhaust system.

To describe my vehicle, I own a 2000 Toyota Revo. This is a utility vehicle designed by Toyota specifically for the asian and south asian market. It's based on a late model 4x2 hilux—minitruck platform with torsion bar IFS upfront and leaf springs at the back. It stops using a disc and drum brake setup. It seats 10 in a 2+driver front, 3 middle, and 4 passenger rear configuration. It is basically a people carrier with folding middle and rear seats for large cargo. Amenities include power windows, 6-speaker radio system, velour seats, and dual airconditioning.

It runs on an NA 2L diesel engine(this is where my question is) with a 5-speed manual tranny. To squeeze out every ounce of hp and torque from the 2L, I've replaced my oem intake with an aftermarket cold air unit. I'm currently deciding on a custom exhaust system. I'd like to get anyone's opinion on which is a better system for the 2L diesel—a 4-1 or 4-2-1 configuration? The 2L's sweetspot is at 2000-2500 rpm so I'm thinking of having longer primaries. 36in x 2.25in diameter pipes seems to be the best. I'll end it with a straight-thru muffler for a nice tone. The engine sounds like a heavy breather with the cold-air intake installed(I like this very much)

Both hilux and revo front dimensions are about the same so the engine bay has enough space for me to work on. And the revo is only for street use as a daily driver. Hope I can get some advice from anyone here. Thanks very much.

 

[Jonathan_Ferguson]

My Hilux has the 2L and on it's second rebuild it runs beautifully all the way to the maximum speed limit of 110km/h where the engine is operating at 3,200 RPM.
On it's first rebuild it was difficult to exceed 80km/h. - The differences between the rebuilds is that the bores were honed with emphasis of prominent cross hatching and the injection pump was accurately rebuilt to OEM specifications.

I shift up gears at 2,500 RPM and back down at 1,500 RPM - The only time I exceed 2,500 RPM is when in fifth gear.

I'm currently in the process of building an exhaust, the pipe size is as per OEM which is 1.5" schedule 5, and will have a straight through silencer. The manifold is original and the front pipe is an aftermarket piece matching the original layout.

I believe cold-air intakes are snake oil.

 

[fjs3]

Thanks for the info.

My 2L hasn't been rebuilt yet, it already clocked up 255,000km++ on the odometer. I just keep to the regular maintenance schedule for the engine—I swapped the old timing belt, engine oil, glow plugs, and fuel filter just recently. An oil catch can will be next.

I was able to push the 2L to about the same max speed as you did on a straight run, but only for a minute or so (didn't want to do anything that may damage it and an engine rebuild will cost an arm and a leg here).

I also shift up at 2,000-2,500 rpm but it depends on traffic conditions. I can barely get up to 3rd gear here on rush hour. So I prefer to leave work at a later time when the streets a less congested.

Have fun with your exhaust build. I still have to save up for mine. I'm going for a full exhaust rebuild with custom manifold. The pipes will still follow the original layout and will be clad in header wraps to keep the heat in. I decided on slightly larger diameter pipes to get the engine exhaling better—again, to gain a bit more the hp and torque without having to get a turbo.

 

[cody c]

Your headed in the right direction, over sizing the system should help more then whether its a 4-2-1 or 4-1.

But I would I would go 4-1 myself just as it may balance the pulses of gas from each cylinder a bit better.

I had a "straight through" style muffler on my NA 3B once upon a time, was great until the first long road trip, nowadays I'm much more content with a quieter system and wouldn't go back.

It seems you care for your revo very much, make sure your coolant system gets preventative maintenance, as the word is the head problems are very much related to heat.

 

[fjs3]

Your headed in the right direction, over sizing the system should help more then whether its a 4-2-1 or 4-1.

But I would I would go 4-1 myself just as it may balance the pulses of gas from each cylinder a bit better.

I had a "straight through" style muffler on my NA 3B once upon a time, was great until the first long road trip, nowadays I'm much more content with a quieter system and wouldn't go back.

It seems you care for your revo very much, make sure your coolant system gets preventative maintenance, as the word is the head problems are very much related to heat.

Thanks, I'm kinda looking forward to the intake and exhaust notes the engine will make once I put in the new system. Don't know what the wife will think though hehe.

I actually had to have the radiator repaired yesterday. Summer's here where I'm at and the heat and humidity is unbearable. I was stuck at traffic going to work after dropping off the wife at her office. I was sitting inside with the airconditioning on and listening to glenn frey singing about the boys of summer. Then I thought off how this year's weather is going to affect my cooling system. Soon enough I knew when my temp guage shot up close to overheating. I parked the revo on a curb, opened the hood and saw small fountain of water and coolant coming from a crack in the radiator. Fortunately it happened in the morning so I was able to limp the revo to a nearby radiator specialist and get it fixed. Talk about timing. I can't imagine if it had happened at night. I'd have to have it towed back home with the wife fuming.

So, the radiator's fixed and filled. So far so good.

 

[Jonathan_Ferguson]

Here are awful photographs of my 1.5" schedule 5 pipe Exhaust with Motorcycle Silencer.
Notice that the Silencer's mounting strap is horizontal with the chassis and that the strap did not need to be cut down to affix to the wee bracket I made to utilise the original rubber hanger. It is hard to see but the lowest point of the exhaust is exactly at the same height as the sidestep bracket, fuel tank and across that point of the propeller shaft. The very tip of the silencer is inline with the bottom of the leaf spring.
I have driven around the local residential streets where it's all second and third gear between 1,500 and 2,500 RPM, and I have driven on two major arterial roads with 60km/h limits. In both situations I was amazed at how quiet it was, but I haven't wound the windows down yet.
Before fitment of this system I had run the car around the local residential streets without the secondary pipe fitted, where it sounded like a tractor or small earth-moving equipment on idle-up to run the hydraulics. I have also run the same design secondary pipe as my new setup but without the silencer, where the extra length and four bends made so much difference that the exhaust no longer emitted such a harsh tractor sound.
The bends used were a 15°(Down 15°), a 30°(Up 15°), a 15°(Parallel), and a 45°(Down 45°).