New Merc Racing Heat exchanger, other options?

[Darren McDonnell]

Hi has anyone seen any results of tests with the new design Merc racing heat exchanger. It looks better but with the likes of MRC still saying that Merc is not upto the Job i was wondering if the new one was any better.

I would like to upgrade to keep thing safe once the summer arrives and have been looking at options.

This is what I have in mind without spending 1k+

Jag XK dual stacked system £150 + fitting Kit
Merc old version £350 ish
Merc New £470 ish

Both the Merc ones are me buying Direct.

 

[Simon]

Lots of people in the US seem to get good results with the Merc kit, why does MRC say it doesn't work?

 

[NHN]

If mrc say this, I'd be more inclined to listen.

 

[mercules]

MRC are comparing it to the AMS one which has a upgraded pump. It's not apple for apples.

If you have money then go for belt and braces one with a uprated pump if you want something in-between go for the Merc one with stock 100% pump duty mod.

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[Dippy]

Isn't the 100% pump duty mod only applicable to the b8?

 

[mercules]

Isn't the 100% pump duty mod only applicable to the b8?

Previously I read quite a few discussions on US forum particularly on the logging Vs stock setup. Some of the cars were B8.5. Someone also posted wiring diagram which was similar between a 09 and 14 S4. When I did mine I did notice I could hear the pump more soon as ignition is on. I put some connectors on the end so could revert it if required.

Also I've read (again) some tuners have this mod mapped in more recently.



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[Simon]

I have nothing against MRC but they don't list a price for their option or give any kind of details of what it entails on their website.

So if they are saying the Merc option isn't as good as their option I would like to know why. These are the same people that charge £450 for a pulley that can be had for £150, and that doesn't even include fitting so forgive me for being skeptical.

 

[mercules]

I have nothing against MRC but they don't list a price for their option or give any kind of details of what it entails on their website.

So if they are saying the Merc option isn't as good as their option I would like to know why. These are the same people that charge £450 for a pulley that can be had for £150, and that doesn't even include fitting so forgive me for being skeptical.

During a map tweak they told me face to face a forced induction car would make less power if you removed the back pressure. Specifically my car. Never went back.


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[Darren McDonnell]

During a map tweak they told me face to face a forced induction car would make less power if you removed the back pressure. Specifically my car. Never went back.


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Yer they told me by email the same thing, quote if you remove the cats it will loose power this is the 3rd forced induction i have tuned and the first time i have ever been told that even if the others where Turbo's.

Issue I have is i dont fancy the cost of starting with the mapping again with someone else.


MRC have told a few guys now that the Merc cooler cant cope with the extra ratio of a dual setup. I dont think I would be looking to go all out for a Dual setup anyway as I have a high Miles and also there is the charger clutch to Protect, but i was wanting something that will keep AIT's in check if I do a track day Or two. I have also been reading about the Ported blower which has seen good results for an MRC stage 2 car.

 

[mercules]

Yer they told me by email the same thing, quote if you remove the cats it will loose power this is the 3rd forced induction i have tuned and the first time i have ever been told that even if the others where Turbo's.

Issue I have is i dont fancy the cost of starting with the mapping again with someone else.


MRC have told a few guys now that the Merc cooler cant cope with the extra ratio of a dual setup. I dont think I would be looking to go all out for a Dual setup anyway as I have a high Miles and also there is the charger clutch to Protect, but i was wanting something that will keep AIT's in check if I do a track day Or two. I have also been reading about the Ported blower which has seen good results for an MRC stage 2 car.

Agree with you, I actually thought the exact same thing. I wanted to change tuner to IE with the map update box but already sunk too much in to justify change and tbh IE came too late in the platform for me.

If you look at the quickest tuned cars on this platform it's a even mix of cat and decat. When they did the tweak I made a tiny bit more power on DP.

I don't know if you noticed but when you boot it on a really cold day you can feel how harder it pulls compared to warm day. The Merc racing changes this a little and it definitely improves the recovery to go again. I am happy I changed it as stock was really bad in summer. AMS if you got £2k spare


I've seen some users put a 2nd pump on the system so it runs two stock pumps and it's supposed to be better as its helping flow for the larger HX.

You planning on doing ported blower and throttle body?


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[Simon]

I spoke to MRC when I was rebuilding my car, they told me I would get an “easy’” 500bhp with just a remap and a single pulley and the clutch would be fine. With quite a bit more reading I realised this was not possible so went another way.

Even with an uprated clutch fitted I can’t launch with just 400bhp (should have gone for a better clutch while I was doing it but didn’t want a lightened flywheel.)

I am sure they have done some good things but I wouldn’t trust them with my money

 

[Dippy]

I can monitor my IAT whilst driving as it's on one of my FIS-Control MMI lists. I also have one which is "torque reduction due to high IAT" which has always been 100% (which doesn't mean 100% reduction - rather the opposite). I have only ever done "fast road" driving and IIRC one summer I saw IAT peak in the 60C region and I read somewhere that's about the max the ECU will tolerate before retarding? I feel fairly happy that I'm OK with the stock cooling for my style of driving, especially with the improved intercoolers used in the CREC engine. But I certainly feel that anything more such as a track day would take the cooling system over its limit.

I remember (early 2017) asking Doug @ MRC about improved cooling and he mentioned that they can uprate it but that they hadn't done many on this platform. Fortunately I'm happy with my "off-the-shelf" stage 2 because I don't believe that I'm wrong in suggesting that for most tuners 80%+ of their business is simple "off-the-shelf" stage 1 & 2 tunes and when they do more it should really be considered custom/prototype. As such their experience may not be any better than that from individuals on web forums. One thing for you to consider @Darren McDonnell is that you have the CREC engine and so you can't 100% rely on any information either from the web or tuners which is based on experience of the previous engine. Remember that in North America the CREC was never used in the S4 or S5, only in the A6, A7 and IIRC Q5.

 

[Darren McDonnell]

Cheers Dippy. Its good to know that your AIT have always been in a reasonable range. After reading on here about the Dual stacked cooler and also the Gen1 Merc racing they both seem to give the same sort of result, which is a reduction of around 10c on a 1/4 mile run.

I know there will be some issues with most coolers on track days if not given the correct time to cool down as the heat soak with also play its part. I had a turbo car many years ago with a charge cooler set up and this suffered the same.

I may just try the Jag dual stack to see how i get on as i wont be doing track days every week just the odd one a year and mainly the start and end of the year.

 

[Darren McDonnell]

Agree with you, I actually thought the exact same thing. I wanted to change tuner to IE with the map update box but already sunk too much in to justify change and tbh IE came too late in the platform for me.

If you look at the quickest tuned cars on this platform it's a even mix of cat and decat. When they did the tweak I made a tiny bit more power on DP.

I don't know if you noticed but when you boot it on a really cold day you can feel how harder it pulls compared to warm day. The Merc racing changes this a little and it definitely improves the recovery to go again. I am happy I changed it as stock was really bad in summer. AMS if you got £2k spare


I've seen some users put a 2nd pump on the system so it runs two stock pumps and it's supposed to be better as its helping flow for the larger HX.

You planning on doing ported blower and throttle body?


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I dont think I will be going for the throttle body, well not just yet any way its more of a long game with me. I like to keep adding and playing but it is still the family car.

There was a guy with MRC stage two and had the Ported blower mapped in and saw 20-25Hp extra with no other changes. this seems like a good return and making the airway more efficient is also supposed to help keep the temps down.

 

[Darren McDonnell]

Isn't the 100% pump duty mod only applicable to the b8?

Do we know if this is mapped in on our versions?

Is there any way to check it with VCDS at all