11 replies to this topic

[Zik]

Hi all

 

My car has a 3" DTM exhaust on it at the minute from the previous owner. Now I know that is a bit of a marmite statement, some people love those things and some despise them. Personally I love the exhaust note and it looks pretty damn cool. BUT that the point is not.

 

On a standard 998 engine that exhaust pipe must be doing my performance no favours, does anyone know what it would do to a 1275? Building one up at the minute and I might have to add a pipe to the shopping list. The mixture never wants to sit right at the minute and while I'm sure the carb could do with a rebuild I think the pipe is playing hijinks as well. Would switching to an rc40 pipe improve matters? Does anyone produce any sort of twin exit exhaust in a 1 3/4 form?

 

 

[HarrysMini]

Even on a 1275, a 3" DTM would ruin performance. An RC40 or other 1 3/4" is the best for a standard/slightly modified 998/1275.

 

Have a search on the forum for DTM performance, you should learn lots.

[Cooperman]

If you want a twin exit exhaust on a 1275 then each final outlet pipe needs to be no larger than 1.25" diameter. the ideal is a single outlet pipe at 1.75" internal diameter. Fort a 998 a pipe of 1.625" is ideal.

For optimum performance the exit speed of the exhaust gas is very important. An oversize rear exit causes the gas velocity to decrease with a local increase in gas pressure and this really screws up performance.

A 1.75" pipe on a 1275 is at its best at between 5500 and 6500 rpm.

The DTM and other oversize or large twin exit systems are best described as 'power sapping noise boosters'.

Best systems are Maniflow or RC40 twin box single exit 1.75" bore.

[Zik]

 

The DTM and other oversize or large twin exit systems are best described as 'power sapping noise boosters'.

 

 

Says it all really! If I were a vain man (which I'm not honestly  ) and wanted to keep the pipe for looks would a DTM style exhaust which had inner pipework at the correct diameter achieve a good compromise? Think I saw one on ebay with the 3" outer pipe but 1.75" inner piping

[Cooperman]

As most on here know already, my interest is in the performance of the classic Mini, so a 'dummy' pipe has little interest. I guess it would work so long as the 1.75" pipe came right to the very end of the 3" part, or even projected beyond it slightly. Would look a bit silly, but to those who are into Mini performance all the huge pipes look a bit silly, although each to his own.

To the 'engineers' amongst us, that which is right usually also looks right and an upswept centre-exit 1.75" Maniflow looks right because it is.

[HarrysMini]

Not to mention that it is technically illegal to use a DTM on a Mini on the road as it is significantly louder than standard.

[Cerberus]

Not to mention that it is technically illegal to use a DTM on a Mini on the road as it is significantly louder than standard.

 

Spoilsport,

[Tamworthbay]

As most on here know already, my interest is in the performance of the classic Mini, so a 'dummy' pipe has little interest. I guess it would work so long as the 1.75" pipe came right to the very end of the 3" part, or even projected beyond it slightly. Would look a bit silly, but to those who are into Mini performance all the huge pipes look a bit silly, although each to his own.
To the 'engineers' amongst us, that which is right usually also looks right and an upswept centre-exit 1.75" Maniflow looks right because it is.

+1 and maniflow are a pleasure to deal with.

[Zik]

I did have a noise complaint from residents of the road leading up to work a while back   I think a 1.75" centre exit should do the job nicely. I should be fine using just a backbox?

[Tamworthbay]

My maniflow is a single box system and it's not very noisy, especially at low revs.

[cradley-heathen]

i have used single box rc40s on 998 engine in the past and found the sound to be pleasant without being loud.

 

i have used a maniflow on one of my cars, and now have a janspeed system on my metro, but they are all much the same in my opinion, they all have the same pipe size, and the boxes are very similar size and weight too really.

 

get a proper exhaust on it and give your neighbours ears a break lol!

[HarrysMini]

In my opinion, a single box Maniflow system has the ultimate noise and performance for a Mini. It's not so loud that you may as well have used a baked beans tin with a length of tube and it's not so quiet that you can't hear the noise your right foot is making. It makes a great note as well.

 

 

Not to mention that it is technically illegal to use a DTM on a Mini on the road as it is significantly louder than standard.

 

Spoilsport,

 

Only telling it how it is. I've been a passenger in a Mini with a single box DTM system that got pulled by VOSA. They did a roadside noise and emissions test. It failed both.