Hi guys,
Although it's a known that the original boosts pipes are routed through the cam-cover because of standard layout logistics, some heat transfer must occur and add to the charge temp versus not running it through the cam-cover.
Has anyone done any research or got any data on what sort of temperature difference there is, or knowledge of whether the rise in temperature is negligible enough not to worry about?
Ross.
i think having the room or routing it would be a problem. I suppose if you made a t piece into the inlet of the charger and blanked the other inlet to charger off you could do it.
I personally found, i got better mpg with boost return mod done, but thats obviously not re-cerulating hot air. Must be a bit of temp difference.
That's only re-circulated air anyway, so it's going back through the intercooler before getting into the engine so changing this pipe routing won't make any difference at all.
As Jezza says though getting rid of this and blanking the charger does make a good difference
Thanks for your replies chaps,
It was a more general question really - my fault as I didn't give you any background. I'm going K03 turbo on my PY, but i'm not going the traditional Rothe manifold route - i'm building my own and moving the turbo elsewhere and as such I have few different piping options for charged air. The easiest may be to utilize the cam-cover to minimize pipework. It would be before the intercooler, but obviously I don't want to heat up my charge temp any more than necessary, so I was trying to understand how much putting it through there heated the air.
The fact that it's the re-circulated air will probably mean that no-one has done the research i'm after.
I didnt realise that was the case, so cheers guys.
Ah I get ya know. Still think you must mean AFTER the intercooler? ???
I doubt it'd heat it up much at all tbh, but I think it will a little.
nope, definitely before the intercooler ;) watch this space.......
If it's pre intercooler then no, charge air will be hotter than cam cover. Energy flow from high to low = heat up cam cover.
Charge air temp ~ 130-180'C (dependent on boost pressure)
Cam cover ~ 70-90'C
So I wouldn't worry about the transfer temp, however the cam cover does go fairly narrow, definite flow restriction, but probably not a problem at ~170bhp (your target power?)
Ahh, that's what I was after Yoof. Cheers pal. Wasn't sure what the charge air temp would be. (Actually, didn't realize it was that hot, but it makes perfect sense.) Cam cover would be around indicated engine temp, yeah - got it.
Hmm, well was looking at throwing 21psi through it - I guess that might be an issue with the restriction at that bore then? I'll do the maths on it when I get a chance, back pressure could screw it right up as you point out.
Just looking at options at the mo. Could always mill it out a bit but it all starts getting a tad tricky.
What's the ID of that pipe? Is it 48mm ish? From memory the K03 compressor outlet only needs 51mm ID pipe, so might not be such an issue.
On the road my post-intercooler inlet air temps were about +25°C over ambient with my old front-mount cooler if that helps. Now running a larger, better flowing intercooler which will hopefully help.
So it it's certainly before the intercooler then the chance of the rocker temps raising the charge temp isn't going to matter? As the intercooler will cancel this out?
But like Yoof says, it's going to be hotter anyway
There's no chance... it's physics!
If anything the opposite of what you suggest.
I'm confused :D No chance of what?
you are confused...
Quote from: Yoof on January 02, 2014, 05:50:55 PM
If it's pre intercooler then no, charge air will be hotter than cam cover. Energy flow from high to low = heat up cam cover.
So basically, the cam cover works as an intercooler. ;D
@Dubstar: If the ID is too small, you could modify the cam cover to fit a bigger pipe, shouldn't be to much of a problem I suppose.
Quote from: OCDmatt on January 03, 2014, 01:06:17 PM
I'm confused :D No chance of what?
You can't heat the charge air up with the cam cover, the charge air is at a higher temperature than the cam cover.
scully - I guess your restriction is the camshaft, not sure how close the standard pipe is...
Got ya, no I knew that. I was just saying that if it's passing through there before the intercooler it wouldn't matter anyway.
Quote from: Yoof on January 03, 2014, 03:07:30 PM
scully - I guess your restriction is the camshaft, not sure how close the standard pipe is...
I don't know either, but you could open the top, make this bigger, and leave the bottom in place. Just need to figure out the room between the cam cover and the hood.
K03 outlet is Ø40 ID. Cam cover pass-through is Ø36 ID, so it would represent a 10% restriction (in terms of area.) That's if the area of the Ø36 remains constant through the profile change inside - which I guess it should, couldn't easily measure it.
It would be possible to do what Scully suggests but the cam cover is cast ally so it would be a tw@t to weld - if thats specific mix of aluminium would take weld at all.
Looks like it's best to leave it out if I can get away with it.
Wasn't there a fancy PY rocker cover that'd had the stock hose pass-through milled out and replaced with some pipe insert instead? Can't remember whether it was something offered by one of the German tuners, or whether it was a one-off on a show car somewhere. Or maybe I'm imagining it!
I reckon the 10% restriction might be worth the sacrifice if it makes the packaging nice and neat, especially if it reduces bends etc. elsewhere. Still intrigued as to what you're planning Ross!
cover wont be that shit to weld as a few people have cut the pipe ends off and welded over the top.
the pipe itself is a little squished in the middle too- presumably for clearance in the head.
Ross- I've welded to it (with a MIG) wasn't too bad :)
(http://img.photobucket.com/albums/v251/Young_Un/Mk3%20Re-Build/DSC02037.jpg)
Probably got a spare G40 cover somewhere too... I'll have a dig around
This might be a helpfull image. ;)
(http://rs1279.pbsrc.com/albums/y523/richard-polo/Mobile%20Uploads/G40_zps9034868e.jpg~320x480)
That look quite smart, have they cut the top half of return part out of the rocker cover?
Yeah good point guys, I have seen some welded come to think of it. Should of remembered. And thanks for the engine & engine bay porn too! I think as I've not got the airbox there, I've probably enough room to get round the timing belt cover without using the cam cover pass through.
I'll find out soon when I do the dry build of the engine bay. YEAH BOY! ;D
Quote from: scully on January 05, 2014, 12:37:06 PM
This might be a helpfull image. ;)
(http://rs1279.pbsrc.com/albums/y523/richard-polo/Mobile%20Uploads/G40_zps9034868e.jpg~320x480)
That's the one I was thinking of!