muffler for 2.7 mfi

[obrut]

I have a fairly warm 2.7 in my race car - 10.5:1, GE80 etc - with a nasty flat spot from about 3300-4000 rpm.

Nothing we've tried has worked and the last part not touched is the muffler - a 2-in, BIG single out Monty (that appears almost completely hollow).

So I ring Monty mufflers and, lo and behold, speak to Monty - I tell him I've got a MFI engine with this muffler and he pre-empts me and says "Oh, you shouldn't use that you'll get a big flat spot. I make a special 6-baffle for MFI engines as they need more back pressure" Its a 2-in, 1 out - and apparently won't work with dual outs (centres or ends) due to some space issues.

I think this must be the 'special MFI monty muffler' that Steve Weiner has referred to in the past.

So before I place the order...has anyone else had success with anything else - esp centre twin out?

[Grady Clay]

Ryan,

One of the cardinal facts about MFI is it is a complete “System” where all the components were originally matched to get the great performance. When you “mix & match” and use aftermarket parts there are some issues that are difficult to overcome in some situations.

I would recommend you find an original or OEM muffler to borrow and carefully reset the MFI (knowing where you start.) Report the results.

You say this is a track car. What is the RPM range that is used? Is it also used on the street, highway? Do you change things for different situations?

Best,
Grady

[obrut]

Thanks Grady

I'm hoping to borrow a stock muffler next weekend - if this improves things then i'll try the "6 baffle special"

My mechanic services another 2.7 MFI car (a real 73 RS) with the same muffler as me and it also has the same flat spot - we'll hopefully repeat the test on his car

My car is used for track and tarmac rallies - I can live with the flat spot on the track but its a PITA when rallying.