Exhaust performance - Japspeed vs Mongoose

[androo007]

Hi guys

Watch out....anal warning.....

I currently have the Japspeed exhaust on my turbo, and although I like it, I think the rest of the world doesn't.

I have a mongoose exhaust in the shed in really good condition, so tempted to swap over.

Both systems are 3" inlet, mongoose slightly smaller outlet.

I'm running external wastegated turbo.

Now I may well be wrong, but with the bigger silencers on the mongoose, could this cause a drop in power with the increased baffling? Assuming the Japspeed is the most free flowing as it's just wallop straight out, could it be offering more power than a mongoose?

Hard to say without back to back dynos for sure.

Im tempted to say NO on the basis I have a screamer pipe, so surely any extra back pressure created is non void by the screamer anyway?

What's your thoughts, geeks?

[SonicSW20]

Not going to make any difference in a stock turbo.

[androo007]

It's not a stock turbo though. Td06 20g. Looking to map at 20-21psi so flow is something to consider.

[C35Rob]

Without doing back to back dyno tests you're only going to be guessing. But based on the facts that japspeed is the cheapest exhaust you can get, made in China from low quality materials with no consideration for performance and mongoose is a reputable, quality product I'd choose the mongoose every time.

[androo007]

Yeah, I did wonder that. Although sometimes you do get good results from these cheap exhausts. Back in the day I had I think at one point the UK NA record for a hyundai cope and dyno tests got the best results with.....the cheapest XS power exhaust

[craig]

No question mate, the Mongoose is a quality product, the Japspeed, a readily available, mass produced, cheap exhaust. Nothing wrong with it though, it does what it says on the tin.

If I had a Mongoose sat in my garage, the JS would be up for sale.

Only way to prove, is to do back to back dyno's with both fitted. I wouldn't need dyno tests to do that though, I'd cut out the middle man and fit the Mongoose.

[androo007]

Sold! Thanks guys

Maybe I'll keep the JS for another day. You're right Craig they look great and do sound cool but I live in an elderly area and think the curtains are twitching and neighbourhood watch meeting agendas being written.....

[2mad]

mongoose is 70mm pipework and crapspeed is 76mm .. i had a mongoose and it produces a heavy bass tone on tick over .. sat in the car it seems quiet if i went in the house while the car was warming up my god the place was shaking with a bass boom, this did not make me popular

Crapspeed is also very loud from imoc member accounts


Anyhoo not very neighbour friendly was where i was going with this post

[craig]

Not sure on the Japspeed being loud.

Mine is coupled with a berk decat and its no louder than any other aftermarket turbo exhaust.

I also did 1650 miles round the Pyrenees this year and it didn't drone or do mine or the missus' heads in.

[CalMac]

Screw the neighbours! As long as you're not sitting revving the boobs off it at 6am on a Monday morning then you're not being unreasonable. The car has passed an MOT therefore they can just deal with it

Another vote for the Mongoose though. I run a Phoenix Power and that's pretty quiet but a bit of a mission to find

[2mad]

Screw the neighbours! As long as you're not sitting revving the boobs off it at 6am on a Monday morning then you're not being unreasonable. The car has passed an MOT therefore they can just deal with it

Another vote for the Mongoose though. I run a Phoenix Power and that's pretty quiet but a bit of a mission to find

Funny you mention mot .. my friend runs a garage and booked my car in at a mot testers .. and the chap said it exceeded noise levels or some sh/t but passed it because it was my friend ... just saying ... maybe im getting old my first car had a cherry bomb on it lol .. yeah sod the neighbours lol

[androo007]

So I got the mongoose out today and...

It is a 3" pipe... up to the downpipe. It's then stepped down to a 2.5" on the 3 bolt flange.

My downpipe is 100% a 3" so now unsure.

The step is only a couple of inches but in theory would be a restriction, right?

Or..... is it even of concern as I have the screamer pipe anyway?

Normally I would not be bothered and it'd be easy decision, but I want to make sure I get every hp available without upping boost!

[2mad]

So I got the mongoose out today and...

It is a 3" pipe... up to the downpipe. It's then stepped down to a 2.5" on the 3 bolt flange.

My downpipe is 100% a 3" so now unsure.

The step is only a couple of inches but in theory would be a restriction, right?

Or..... is it even of concern as I have the screamer pipe anyway?

Normally I would not be bothered and it'd be easy decision, but I want to make sure I get every hp available without upping boost!

I remembered the step , thought it was 70mm .. if you running a screamer you will be fine .. thats alot of gas the exhaust does not have to deal with .. you could get the step removed from the b-pipe if you know a fabricator

[Martin F]

I would keep the japspeed on, looks better, Imo sounds better and I doubt very much at your power levels there will be any difference between the two.....
Especially as you are using a screamer pipe, takes some pressure off the exhaust system...

[gnzyza]

Japspeed , very uncomfortable around 3k, or it could be poly engine mounts or both.

Anyone with this exhaust and not running poly mounts find it drones at 3k?

[C35Rob]

So I got the mongoose out today and...

It is a 3" pipe... up to the downpipe. It's then stepped down to a 2.5" on the 3 bolt flange.

My downpipe is 100% a 3" so now unsure.

The step is only a couple of inches but in theory would be a restriction, right?

Or..... is it even of concern as I have the screamer pipe anyway?

Normally I would not be bothered and it'd be easy decision, but I want to make sure I get every hp available without upping boost!

I mentioned this (2.5" being a restriction) to my dyno operator when I took my car to the rollers, I was unconvinced but he said its nothing to worry about, and he's built 500bhp evos that run 2.5" exhausts

the area of a 3"/76mm pipe is 45.36 CM2, the area of a 2.5"/63mm pipe is 31.17 CM2, but if you have a 38mm screamer pipe the area of that is 11.34 CM2 so 42.51CM2 total - very little difference compares to a 3" exhaust with a plumbed back dump pipe, probably better anyway since you don't have the two different flows converging

there's a B2B dyno sheet here from KO racing

http://www.koracing.net/viewarticle.php?article=7

which shows very little real-world difference between the two

[androo007]

Wow what an answer! Cheers Rob

[mrfil13]

In a similar predicament to yourself, i have a PP Dep 2 Std on the car, sounds really nice and ear friendly on a motorway. It sounds/looks like the y section is starting to go. I could get it repaired but there's a crack in one of the tailpipes.

I also have a Japspeed in the garage.

Choices are either get the Dep2 repaired although i've not found anywhere near cambridge yet or potentially get one of the apexi exhaust valve style things but not sure if they can be fit without modification. Yet to find any examples of people installing the valves on a MR2 though.

My Japspeed had bungs that i could bolt onto the tailpipes, looked abit naff but did help alot.

Alternative i was considering was finding somewhere that could replace the japspeed mufflers with something much bigger.

[benjo]

I run a fujitsubo legalis r on a n/a I've had complaints
That it rattles the windows of man across the road!!!
But since he's a pr@&k I don't care
Told him he should ov bought better quality Windows as mine
Don't rattle

[alanmr2turbo]

Japspeed , very uncomfortable around 3k, or it could be poly engine mounts or both.

Anyone with this exhaust and not running poly mounts find it drones at 3k?

I have Japspeed and poly engine mounts. It does drone a little at a certain rev range but then i just turn up my stereo up which is running 2 x 12" subs so I dont hear any engine noise LOL