KWE Intercoolers - My Review

[IanH755]

***EDIT*** Feb 2020 - Wagners have now created a C6 RS6 replacement Intercoolers for around £2500 inc new radiators and new crash bar which is now at a pricing mid point between the HS Marstons and the KWE IC's but with a proven better performance than either with 1 car hitting almost 1100hp with them fitted.

***EDIT*** Early Oct 2021 - I've now swapped from the KWE I/C's in this review to a set of the Wagners mentioned above, just waiting on a remap now!

***EDIT*** Mid Oct 2021 - I just had my car mapped for the Wagners - made 930hp and 1125nm - way better at the top end, better cooling and flow rate meant the redline could be increased to 7500rpm!

*******************************************************************************************************

I’ve already covered some of this in the HS Marstons thread I posted.

As part of my research into the spec for my car the intercoolers were another thing which seemed to be an expensive and time consuming part to source.

KWE wanted over £1k for their “untested in the UK” IC’s and the only other one we knew of was the HS Marston’s ones that Classba and Brett have which, again, had been posted as costing around £5k-6k originally (price since dropped to £4k).

I decided to try the KWE’s, mainly for their price and also because no-one had fitted them and done any dyno runs to performance check that I knew of (only 1 other with them fitted I believe), so I thought I would be the guinea pig for these.

MRC had the task of fitting them and we knew from a Facebook post by SW Auto’s in Kent (who’d fitted a set to the garage owners own RS6) that fitting was not “Plug and Play” as described on KWE's website. It turns out the UK spec RS6 has some coolant pipework routed differently to the Euro Spec RS6 so while in Germany KWE had no issues fitting them (other than modifying the air shrouds/guides to fit the bigger IC) in the UK we have a pipe that wraps around the right IC. This pipe doesn’t fit the much wider KWE IC’s so the pipe has to be modified (either replaced with a flexible pipe or a new solid pipe made). The shrouds (or air guides) also needed some custom work to fit the bigger IC so mine have been adapted by MRC with a metal shroud “extension”. KWE have since released a new set of shrouds for around 600Euros but that happened after I’d already bought mine so I’ve not had these fitted and don’t really see the need to either to be fair.

So, performance figures! Well it’s a mixed bag of good & bad which doesn’t sound great but let me explain. They do make the power! They made 920hp no problems which is great for their cost, however, there are two “issues” they have which need to be mentioned.

Their flow rate above 6500rpm seems limited and, as they were making no extra power above that, Doug decided to reduce my limiter back to OEM 6500rpm. This isn’t a huge issue as they still make 900hp+ at that rpm but something to be aware of.

Their biggest problem is that they suffer from heat soak when the car is not moving, due to a combination of having no fans fitted (I felt they block the air passing through the core when driving and I’d rather have more cool air when driving) and having a thick metal core which absorbs heat and doesn’t cool back down easily in static air. On the roads I’ve had absolutely no problems or power issues but when in static air (dynos, start line on drag strips, traffic light grand prix etc where the car isn’t moving) after repeated runs they just couldn’t cool down quickly enough between runs which raised the intake temp and robbed power. In fact Doug said my 920hp runs at MRC dropped to 900hp within 3 consecutive runs and to 880hp after a further 5-6 back to back runs and that is with some very good dyno cooling.

Worse still, at the Surrey Rolling Road day the car had not been “prep’d” in the best way prior to the run. I’d been out for a blast, then switched it off for 20 mins, then sat idling for a further 10mins adding even more heat soak before the run which was done without any IC fans (only one engine bay fan so the worst possible setup imaginable) and the power had dropped to only 780hp!!!! Even cooling the IC’s by flicking some water on them brought them back 30hp to 810hp showing how poor they are when in static air (when the car isn’t moving).

So, my review – They work, they’re cheap and they’re adequate for 900hp+ but just stay away from dynos and drag strips as heat soak is an issue.

Will I be changing mine? – It depends on the cost of the Sportmile ones to be fair. Now I know the KWE’s “limitations” I can work with those as I rarely do dynos/drag days/traffic light grand prix but if there’s a better IC for a respectable price then I’d consider it. However I feel the Marston’s are still too expensive for what they are, now I know the cost of the cores.

[Ungjaevel]

Great write up, glad you got the power needed. Problems are just obstacles to overcome. Assuming fitting a fan - any fan - is near impossible?

[IanH755]

No they're designed to fit the OEM fan if you want to fit them.

However the core of the fans restricts the airflow to about 40% of the cooling fins so I made the choice to leave them off as I personally prefer to have 100% of the cooling fins available for cooling when your driving (which is how my car spends 99.9% of its time), rather than having fans to help during the very short time you're static and want to launch off the line.

Again, once your driving the IC's are fine although it's still fairly "cold" here (<10'c) so maybe once it gets up to mid 20's in the summer it'll be different?

[FUBAR]

Euro spec cars also have cooling pipework routed around the right hand ic. Don't ask me how I know.

The KWE ic's are far from plug and play on euro spec cars no matter what KWE is saying.

[porteriow]

Hi Everyone,

I have just bought some of these KWE intercoolers I wish I had read some more on here first with regards to the fans etc.
I live in Dubai, so heat is the main problem out here. What do you think about keeping the fans on out here as its over 50 Deg C in the summer in the day and 35 at night? I run a mild Stg2 Revo map for summer use and I'm running TTE850 turbos and I'm looking at going for the loba fuel pump soon and a de-cat. Winter is around 3 months, when it goes down to 15 deg C or so minimum and i run a more aggressive map.

Best Regards

Richard

[FUBAR]

When I was in contact with KWE they suggested to use the OEM fans. This was the best compromise at the time, but that all depends on how you use the car. For your area it is probably the best solution.

KWE has also experimented without fans and with bigger fans. They went back to recommending OEM fans.

[porteriow]

Sounds like a plan I was a bit worried at first that they would not fit, I am not sure if there is extra cooling for cars with Gulf spec due to the high ambient temps here. I will get them installed in the summer when I go away so I will have to wait a while to see.

[IanH755]

Yes the OEM fans fit and, for Dubai, I'd definitely fit them.

[c3nturi0n]

Great write up... and comments.

Drive side IC developed a leak and i'm contemplating to replace both during winter with KWE (considering that cost of single OEM is the same if not more expensive than BOTH KWEs). Any suggestion of whether to keep the fans or completely remove from the setup? Unfortunately my car spends much of time in Lon traffic with occasional blast on motorway's.

One other thing (and this one is for Ian) - did you simply disconnect you fans or removed them altogether? Assume no error on the dash etc.

[IanH755]

From my experience - traffic & cities etc needs fans regardless so while I completely removed my fans to allow more cooling air to hit the IC's when driving at speed (spend most time in countrysides and fast roads) if I lived in London I would never remove the fans.

One thing to remember is these KWE IC''s are not direct fit replacements, they needs the "ducts/shrouds" from the bumper to the IC modding to fit properly so add that cost into the buying price too, although KWE also do a nice set of CF ducts/shrounds for about £600 which is ridiculous but so tempting

[c3nturi0n]

cheers Ian... point taken.

I just bought OEM IC off the friend who bought it by mistake... super cheap and I guess Christmas coming early for me ("change" will be well spent on other mods, most notably Maxton front lip, ARBs and fixing the p/s pump).

[c3nturi0n]

off the top of your head, is it worth changing any other parts when replacing IC's? e.g. rubber hose that connect to IC.

[IanH755]

For me I say yes but for others you real;ly have to look into the "cost vs benefit" as it makes very little difference to performance on anything OEM or stage 2 TBH.

The OEM pipes are very thin so can expand under boost but, TBH, they don't seem too bad for stock boost pressure or even stage 2 but the thicker silicone pipes will resist that "expanding" under boost much more allowing you to hold a better boost level plus, being thicker, they're less likely to be damaged. However I very much doubt you see or feel any performance difference on a stock car, maybe a few HP on a stage 2 car as you can hold the boost better but for me it was a nice decorative improvement added to a few minor performance benefits.

[c3nturi0n]

For me I say yes but for others you real;ly have to look into the "cost vs benefit" as it makes very little difference to performance on anything OEM or stage 2 TBH.

The OEM pipes are very thin so can expand under boost but, TBH, they don't seem too bad for stock boost pressure or even stage 2 but the thicker silicone pipes will resist that "expanding" under boost much more allowing you to hold a better boost level plus, being thicker, they're less likely to be damaged. However I very much doubt you see or feel any performance difference on a stock car, maybe a few HP on a stage 2 car as you can hold the boost better but for me it was a nice decorative improvement added to a few minor performance benefits.

Cheers Ian.

Any places that you could recommend to source silicone pipes?

[c3nturi0n]

For me I say yes but for others you real;ly have to look into the "cost vs benefit" as it makes very little difference to performance on anything OEM or stage 2 TBH.

The OEM pipes are very thin so can expand under boost but, TBH, they don't seem too bad for stock boost pressure or even stage 2 but the thicker silicone pipes will resist that "expanding" under boost much more allowing you to hold a better boost level plus, being thicker, they're less likely to be damaged. However I very much doubt you see or feel any performance difference on a stock car, maybe a few HP on a stage 2 car as you can hold the boost better but for me it was a nice decorative improvement added to a few minor performance benefits.

Cheers Ian.

Any places that you could recommend to source silicone pipes?

hi Ian, do you recall what is the length of the lower IC hose? and also what is the diameter as I'll try and source some aftermarket ones?

ps. lead time for KWE is around 4-5 weeks .