View Full Version : what is IC and reversing pipes?

Tuesday 29th March 2005, 23:01
Can anyone explain what this is and what it means and does etc?


Wobbly Dave
Wednesday 30th March 2005, 00:19
IC is short for intercooler.

Reverse IC is a former setup of early T5s. I am yet to be convinced. The piping on the early T5's such as Pedro's is shorter because the air flows through the intercooler in the opposite direction to mine and yours. The principal reason for wanting it in that configuration is the distance is shorter between the compressor and the throttle body. Problem was on the early models, in cold countries, this early config meant there were issues with the throttle body icing up. Bits were changed in the design.

IMHO it is a complete waste of money and time installing it. The charge temp of the gases under the same pressure in either config will be the same - as the volume is fixed.


I also doubt that the 30cm or what ever distance you shave off will have any difference on turbo lag either.

Reverse IC :tombstone

If you don't have it - don't worry. If you do - well that's just fab! :crazy:

Wednesday 30th March 2005, 00:26
If Volvo changed this item to stop throttle body icing would it not suggest that intake temps were lower?

Wobbly Dave
Wednesday 30th March 2005, 00:36
I think we are talking about Sweden and Scandinavia to be honest - so I am talking proper cold. Not your average sorta-chilly-day in Kent, north wind blew a bit - but real brass monkey/welding torch kinda cold.

This is the reverse IC. The charge pipe from the turbo compressor side comes up and over and feeds into the top of the IC.

as most will have seen, the pipe on most 850's comes up and wiggles a bit
and goes to the bottom of the IC. The outbound from the IC comes off the top and into the throttle


It is my opinion, in much that moving your horns makes no difference either, that spending the money on reversing the flow is pointless. But, (as Jezza and this is a big round full-bodied) but if someone can prove conclusively that doing this mod is worth the money - I will be out there buying one as soon as I can. Failing that I will be down Halfords buying extra stickers to make my car go quicker??!

I cannot see the point.

I would like to make it abundantly clear I am not casting aspertions on those that have done it. Purely my own opinion on the matter

Ian C70T5
Wednesday 30th March 2005, 08:11
I have noticed however that the S60 has utilised a similar setup ..


Which is interesting, perhaps Volvo have bought that plumbing back again

Wednesday 30th March 2005, 09:17
Its funny, a lot of folk who are well into their modded T5's have changed to the reverse IC (admittedly most of them are abroad) but they cant all be wrong surely? :confused: And if its being used again on the S60 again it would give the indication that there is rhyme and reason behind it? :duck:


Wobbly Dave
Wednesday 30th March 2005, 09:21
I wish someone could explain the benefits in mechanical terms. As far as I can tell the normal 850 plumbing was put in to sort a problem. The new IC pipework on the S60 is more likely to do with simplicity, space and cost (shorter pipes = less ), IMHO.

Ian C70T5
Wednesday 30th March 2005, 10:17
Shorter pipe also equals less distance for air to flow so in theory its less lag.

If i could get the mod easy enough i would do it and be interested to know the difference. I dont fancy buggering about i want bolt off bolt on changes. its easy enough to do just need the correct pipes

Wednesday 30th March 2005, 23:11
I have a 1994 Turbo that came with this plumming as standard and I have to agree with Dave that I can see no benefit in it either - the pressure in the pipeworkwill be the same no matter what.

The only advantage I can say it might, and it's a BIG might, is that there will be less heatsoak from the engine on the shorter pipework but this will only effect the intake temps at idle (hence throttle body icing in cold countries)?

Pedro Fandango
Thursday 31st March 2005, 16:33
As far as I can tell the normal 850 plumbing was put in to sort a problem
to stop the throttle body freezing in Sweden (why make a different pipework for a different country when you can give everyone the same & save alot of hassle)

The new IC pipework on the S60 is more likely to do with simplicity, space and cost (shorter pipes = less ), IMHO.
the S60R is basically the same block as ours, so if they can fit it in an 850 with the newer pipework i'm sure they could have got it in a S60. As for cost saving the S60R has more computers than a Nissan Skyline so why would they worry about saving a few pennies on a bit of pipe

still not sure what difference it actually does :B_thumb:

Wobbly Dave
Thursday 31st March 2005, 16:53
it could be proved by making the change on the same car and use VT new dyno (when it comes) before and after?

I am still sceptical.