Intake manifold failed - replacement and JHM intake spacer install review

A6 All/ S6 All
#1

So most of you all know about the manifold issues the S6/S8 V10 experience.

I was super fortunate to buy a car that had a failed manifold, the previous owner had the manny opened, and then lockedwired and tried to glue the flaps to stop them rattling for a few miles to sell it…

So the shop I took it to found this, opened it up and removed the mess - reinstall the manifold gutted but with the flapper motors still in place and working to keep the codes at bay.

How it drove gutted:

I had no miss fires or rough idles, It started normally and drove fairly stock. I did approach everyone and anyone I could about possible tunes to “get around” the flaps being removed. All responses including from this forum were very honest and stated “nope you wont get the performance back” but the car will self tune as good as it could.

From 1000-2000rpm it was sim to stock around town, from 2000-4500 there was a flat spot - this was very noticeable if you applied more than 50% throttle within this range, the car would labor or bog - imagine a civic with the airfilter housing removed and a massive pod filter glued to the end. If you smacked the throttle down within this range the car would cough and bog and not understand what was going one. The induction noise was great but torque was down for sure. From 4500-7000rpm was actually really strong, fun and made even better noise. It felt faster up there than before but as has been proven this is not the case. Power was just peakier. Economy was ok, not hugely different from before, 1 or 2 litres per 100kms ave worse maybe. At this point a new manifold in my home country was $10,000.00 or half what I paid for the car…So I made the D to live with it as it was…

I then had one of the flapper motors at the front of the inlet manny burn out, it was not driving anything within the manifold but it was keeping the ECUs happy. So when that went pop the car went into limp mode, the most aggressive I have ever found. It popped the Cam shaft timing adjuster fuse instantly (well hidden in the engine bay) and would keep doing that unless the cooked motor was unplugged (as it was earthing that system out) this limp mode would struggle to get the car to 60mph. It would drive ok cold but as soon as the car warmed up it was impossible to do anymore than limp back home. If you unplugged the motor the check eng light was on, it drove in a variant of limp mode - or maybe it the cam timing was simply pulling from the get go as the car would drive ok and accelerate ok - but nothing like it used to with a broken manifold. A new flapper motor was $1000.00 here, this was super crap as it was going to drive nothing but would get the car to be back at a reduced power and not have an eng light on… All of this was less than ideal on my car which I had owner for 2 months.

After the research on this forum and trawling the globe for the best deals on manifolds - the US of A was the cheapest. I tried everywhere, Singapore, Germany, wider UK, but JHM was the place to go. With the exchange rate the latest version manny with JHM inlet spacers gaskets etc and shipping came to around $3000.00 my money. Bargain.

post install review on next post

#2

New manny install and review

So the parts arrived from JHM in about 5 working days…this was USA to New Zealand, or basically Antarctica! amazing postal service. Packaged super well too.

Everything was dropped off to my shop - I considered doing this myself however I had claimed on a mechanical insurance and as the shop had been into my car I figured it would be a simpler job for them the second time around.

The inlet spacers came with everything needed for install - The job was fairly simple according to the guys. I provided this forums how to guide, they followed most of it…not all but was an easier fix post the install. The guys also did a quick decarbon while they were in there - not a full eat your dinner of it clean but a decent huck out.

So the drive home - I was expected power wheel stands and AWD burnouts…wasnt the case. It drove nicely - the power was flat and smooth but didnt really feel faster in 1st or 2nd around town. Baring in mind the car had been driving in a version of limp mode for months so im picking the ECUs were a bit confused that now she was back to 100% and fueling may have needed to catch up.

Open road

So out we go, smash the go pedal - the biggest notice was not a huge feeling of power but a rapid need to hit the up paddle. The rate of rev was higher, and the pull from 5500rpm was much higher - this is what the other reviews are of the inlet spacers. In each gear at 5500rpm she really pulled much harder - and pulled all the way to 6800/7200…as opposed to tapering off. On a windy B or C style road in Manual mode was where the inlet manifold and spacers came into their own. The throttle response at any rev is now brutal, specifically small throttle inputs - the responsiveness is night and day to pre replacement. The torque of the motor isnt really noticed/felt during 1/4mile sprints or high speed runs. But on a windy road it really shines. The dead spot is now of course gone - its full of Cocaine fueled pleasure and gas gobbling addictive fun.

It is also no longer a one hit wonder… I used to take people out for drives and as most of you know you would get one or two good fast straights out of her before you felt the cam timing pull and it slowed down. The JHM inlet spacers have completely removed this during out of city driving. You can mash away at your hearts content as it just pulls hard time and time again.

Driving home I have a 10-15mile journey, 2/3rds the way home there is a decent descending bend that you can take at about 50mph that leads to about a 1.5mile straight. It was nice and cold out around 10degrees C so I thought id wind her up proper…left her in 4th for the corner and went for the go pedal. The grunt was good and I just kept her flat until I had half a mile to run before the straight fades, my B6 S4 with great smack out of the corner in third, I would be at 120mph or top of 4th gear at this point. I look down and the S6 was at 140mph easily pulling in 5th…a backed out like a girl at this point. smiles all round.

This blast or test was because I had some oil leaks fixed last week and I wanted to beat on her a tad to try and make sure they were actually fixed.

Soon as I was home I popped the bonnet - I looked at two things

A - oil leaks fixed at this point… winning.
B - placed my hand on the valve cover, noting this was a 15 mile or so drive which take me about 20-25mins and I had just 3 mins prior wound her up to 140mph… the cover was id call warm to touch, about the temp of your shower before you would get in. Not hot, but nice and warm. By shear chance I placed my hand on the inlet manifold as I leaned over to look at the back of the engine where the leaks have been. Result: my hand was cold, not luke warm not a touch cooler. But cold. Like the motor has not been run today cold. I retouched bits around the motor - the motor was warm alright, just the manifold had nice cold air (10 degrees C) sucking through it and was smashing it into V10. I was amazing that after that kind of drive with that kind of high loaded running the manifold could be that cold compared to the rest of the engine.

Cheers Chappy

#3

New working IM and jhm spacers make a world of difference. Wish you many miles of happy motoring!

#4

Great review. Thanks for taking the time to put this in. Lots of guys don’t quite understand just how good the JHM intake spacers are and how they make a world of difference. Add in the working intake manifold and your off to the races. Next get the JHM tune and you’ll think you got a hole new car.

#5

Very nice. I am glad I decided not to wait to replace my manifold then. I should receive the new one from JHM tomorrow.

I am going to remove the old one this evening and replace the oil filter housing o-rings and maybe the valley cover gasket as well just in case (if I can get it off without removing the fuel rails).

Then on Thursday, I should be able to install the new intake manifold.

#6

Great news, and good maint items. You will be pleased with the results! Enjoy!

#7

Got the old intake manifold off again yesterday afternoon. Went much quicker this time. In taking the intake off again, I noticed that already there is a little bit of carbon already starting to deposit on the valves. And I am sure most of this is coming from the carbon caked intake manifold.

Hopefully, FedEx will deliver my new manifold today. I may not be able to install it till the weekend as the weather may not cooperate. We have rain and possible storms coming through today.

#8

There can be small amounts of carbon but it would be hard to believe it would be that quickly. What will happen from time to time is that the valve actually rotates enough to expose the back side of the valve you didn’t see before.

Enjoy the new intake. it will be nice to have all that power back

#9

After a second look, you are correct. The valves have rotated and it has exposed areas I couldn’t quite reach.

I received the intake from JHM yesterday and was able to get it installed and get the car running. Took about 3 hours as I was again taking my time to make sure I did not forget anything. I ended up having to replace the 8 bolts holding the throttle body y-pipe to the manifold. It looks like there was previously work done to the car and whoever worked on it before over tightened these bolts. As a result when I was trying to torque them down, one snapped, so I decided to replace them all. Short little delay. Luckily the threads in the intake were not affected.

While I have not been able to fully test the car’s power, I could immediately tell a difference in the sound of air flowing through the manifold. With the old manifold, you really could not hear the air when the car was idling. With the new manifold, you can hear the air whooshing at idle. Really a surprising difference.

Here is a link to my google picture album with some install pictures:

https://photos.app.goo.gl/SrSuEE9KxSz3RECk6

#10

Glad to hear things worked out well after the manifold replacement. Cheers to miles of maintenance free enjoyment ahead.

#11

The intake manifold is such a big part of the 5.2. Its a tough pill to swallow but when it comes down to it its a big hp gain if you don’t have one that’s working.

#12

My IM is also faulty on the flaps. So far, I see three options: Audi IM, JHM IM or have flaps removed. Anyone went for the JHM IM? What makes ot better then the other two options?

#13

From what I understand and what the numbers confirm. JHM gets the latest versions of the intake manifolds. Even over in some cases dealerships. They also offer the intakes at a lowest price you will find. Now in some cases you can find a intake manifold cheeper but what you will generally see is that its part houses that have older stock that they want to sell off. Those intakes generally are the older intakes before the latest updates.

In the end. JHM has been supporting the platform and its always a good idea just to support those that are supporting the platform still.