higsy

Anybody have any heatshield rattling?

williamGT

iTrader: (5)

I wish I knew that before I bought the $50.00 flex tube.

higsy

I didn't say the flex made the sound go away or eliminated the whistle. Mgp said he was going to also add one which I did. Before headers the flex i used off the Hogan DP didn't whistle.

williamGT

iTrader: (5)

What about if I put the flex pipe behind the rear header? cut 4inches off the DTH y pipe.

higsy

I wouldn't go that route if you ever decide to get rid of the Thorley Flex.

williamGT

iTrader: (5)

ummmm....Mybe I'll just buy the heat tape.

Mgpeagle

iTrader: (6)

Here is what I am going to do. I am going to wrap the x-over along with the flex in one pass and then make a second pass over the DT flex to further dissapate the noise. I am also going to add a flex after the headers on the collector where Higsy has his. If it still whistles a bit there isn't much else I can do. Only if DT made the flex after the collector instead we wouldn't even be doing this.

-Mike

williamGT

iTrader: (5)

Curtis Hogan from Hogan performance called me, It will cost about $30.00 to ship to my door (USPS)...So I'm not getting it....Might order from ZZP.

higsy

Why not use the one from your DP7S. You didn't use the Hogan with your headers?

williamGT

iTrader: (5)

they cut the DP and welded to the DT downpipish...so I thought I didn't need it, so the shop disposed it.

higsy

I think you will be happy with wrapping the flex. My whistle is definitely less and non-existent when my cut-out is open.

williamGT

iTrader: (5)

You think I should still put the flex after the collector?

jderou_GXP

Is it possible you are just hitting the resonant frequency of the flex? The tape would serve to dampen the resonance, so that would make sense. Shortening or lengthening the flex would fix it also. If it is a resonance, the pitch of it wouldn't really change with rpm once it is singing. So once you get at the right rpm to get it vibrating, the sound wouldn't change pitch as your rpms climb (until they get so high the resonance stops, which may be well above the rev limiter).
Is this true, or does it change pitch with rpm?

williamGT

iTrader: (5)

What Header wrap to buy????

Mgpeagle

iTrader: (6)

I used 2" wide header wrap made by Mr. Gasket I think???.... It was a fiberglass mesh type. Most of it is all the same. It also comes in a 1" wide too. The 2" wide makes it easier to wrap.

Here take your pick...

http://www.jegs.com/webapp/wcs/store...rm=header+wrap


-Mike

higsy

I used DEI Exhaust Wrap (2" wide) . I have to say though due to the position of the flex I had a hard time getting it started and keeping it tight. Maybe 1" would have been better. I had to spot use pieces of elec. tape to stop it from unwinding.

williamGT

iTrader: (5)

So I guess I'll get the 1inch wrap in black, does it come with the clamps?

Mgpeagle

iTrader: (6)

It usually doesn't come with clamps.

-Mike

williamGT

iTrader: (5)

just ordered black 1inch x 15feet DEI header wrap and metal ties....so how do you wrap it?

gulfstreamcpt

Like Higsy said, it is quite a b*tch to do. I did it as well last week. My results are very much the same as too. I think the whiste has diminished a bit, but is still there. One change I have noticed though is that it stats later in the rev range now. Where it use to begin at 3500 rpm on the nose, it now doesn't start till between 4000-4200. Like Higsy, mine probably isn't wrapped as tight as I would maybe like, but it is just SO HARD to get it just virgin crotch tight with the angle and placement of that flex!!!!!!

Now, I don't know how the GXP's are, but I found it easier to take off the brake master cylinder resivoir and move it out of the way to make more room down in there to wrap... And of course if you have any sort of CAI, you'll need to take off as well..

Now, to keep it tight as you wrap around is a real pain as well. Higsy has a good idea of taping the start of the wrap to keep it from moving as you keep bringing around the rest of the wrap. I thought about doing that, but just got lazy and didn't... (I may go back and try that to see if tighter IS better..) I found it easier to cut a piece of wrap about 5ft long and wrap with that. That was enough to go over the flex 2 tmes, maybe a little more. The more wrap you have to keep wrapping around that flex, the more it just gets balled up and just makes it hard to get all wrapped around. So again, I would just cut off a piece only as long as you think you need... Makes it easier...

So brass tax.... Was this a help to the whiste???? Yes.... Did it work 100%??? No... (Maybe better/tighter wrap would help.. Maybe...) Was it a bit of a bitch??? YEP..... And some of the tricks I used to make it easier are outlined above... Hope this helps...