A rock let to some mods...Merry Christmas to me...

[Silver Streakin]

I had a rock or something make it's way through my grille and punched a hole in my heat exchanger. Thankfully, I was able to get a couple gallons of distilled water and limp it home with only one small spike in temp and I pulled to the shoulder, opened the hood, and added more water. Temp went back to normal and stayed there until got home, and it peed water/coolant on my driveway while I quickly set up ramps and threw down some cardboard boxes and a pan. Got it in the ramps, shut it down, opened the hood and put a fan on it.

2+ years ago, I bought a MercRacing heat exchanger with install kit, coolant, and thermostat from a forum member. With all of the posts about tstat and PCV issues, I had planned to it all at once when one went, but never did. So, I thought I had all of the parts needed. I installed it (minus the tstat), left the bumper cover and belly pan off, zip tied the fog light wiring harnesses and things up...and I took it for a test drive only to find I had another coolant leak. Radiator end tank seeping. Ugh.

I pulled the radiator to make sure I got the correct PN and ordered one from FCP Euro. In the meantime, I'm seeing holiday sales on the forums... and I'm clearly seeing my crank pulley with the radiator out of the way. Hmmmm...

I bought the crank pulley kit from UniTronic to go dual pulley, since it was 10% off and I'll never have this much room to get to it.

Crank pulley installed
https://www.audizine.com/gallery/data/500/medium/3DADEE33-CA1D-4D09-A447-3D0658A40167.jpeg

Radiator installed
https://www.audizine.com/gallery/data/500/30A40536-6851-4B81-81D2-B514454A4C6A.jpeg


MercRacing heat exchanger installed with the screen mesh that my buddy made for the stock heat exchanger. If I had it installed on the stock one, maybe this all would've been avoided. But, now I'm dual pulley!

https://www.audizine.com/gallery/data/500/medium/75FCCC6B-481F-403B-A1CA-EBC4243C39BA.jpeg

As you can see, I flipped it to have it installed with the correct flow from bottom to top with the passenger side low side on that side. This eliminated needing to do 180 and just use 1 straight connector per side. I added some plastic tubing on the hose to the drivers side. Resprayed the crash bar. Done.

I actually drove it with the pulley on stage 2+ software with bumper cover still off just to make sure everything was ok. I can see why people do the crank without the software. It does pull harder down low, but it feels the same up top.

Downloading the stage 3 software with the UniConnect cable was easy, once I used a better laptop. I used an old one from work that was going to be tossed and it wasn't good enough for the job. Take their advice seriously to use a laptop that will do the job. I called UniTronic and they were very responsive and helpful with working through my initial issues with a laptop that wasn't up to the job.

A test drive with the stage 3/DP software and it's addicting to hit the go pedal!

[Lalalalala]

Very nice write up and pics! Sorry about that issue with your stock HX but I'm sure it was all worth it. Any more reaction to the DP power up top with the tune? Any heat soak issues on repeated runs?

[Silver Streakin]

Very nice write up and pics! Sorry about that issue with your stock HX but I'm sure it was all worth it. Any more reaction to the DP power up top with the tune? Any heat soak issues on repeated runs?

Thanks. It was a lot of work in a cold garage next to a space heater, especially having to remove the MercRacing heat exchanger after installing it.

Yes, it definitely pulls better up top with proper tune. I was more just curious. And wanted to test for coolant leaks again.

I have not tested heat soak / back to back runs. I have not really pushed it much. I'm waiting on spark plugs with heat range 9 from FCPEuro.
And it's sub 50*f here the last few weeks with lows in the 20s overnight. Everything is cold.

[01northernS4]

Thanks. It was a lot of work in a cold garage next to a space heater, especially having to remove the MercRacing heat exchanger after installing it.

Yes, it definitely pulls better up top with proper tune. I was more just curious. And wanted to test for coolant leaks again.

I have not tested heat soak / back to back runs. I have not really pushed it much. I'm waiting on spark plugs with heat range 9 from FCPEuro.
And it's sub 50*f here the last few weeks with lows in the 20s overnight. Everything is cold.

Welcome to the uni dual pulley fam!

curious, you being in the US what made you choose uni now over the current king 034, or even IE/EPL/APR?

I love uni with regards to reliability and safety and especially being in canada, but think I'd have a hard time picking them if I lived in the states with 034 pushing the platform soo much, updating, features and being the fastest... Is it your daily and safety/reliability your number 1 concern?

Also, did uni advise heat range 9 and what gap? They advised to keep everything stock for me and also what I've read on the forums here (stock ngk heat range 8 0.32 gap)

Thanks and enjoy!

[Silver Streakin]

Welcome to the uni dual pulley fam!

curious, you being in the US what made you choose uni now over the current king 034, or even IE/EPL/APR?

I love uni with regards to reliability and safety and especially being in canada, but think I'd have a hard time picking them if I lived in the states with 034 pushing the platform soo much, updating, features and being the fastest... Is it your daily and safety/reliability your number 1 concern?

Also, did uni advise heat range 6 and what gap? They advised to keep everything stock for me and also what I've read on the forums here (stock ngk heat range 8 0.32 gap)

Thanks and enjoy!

I purchased my S4 used and the PO had a shop that is a UniTronic vendor to flash it UniTronic stage 1 and install H&R coilovers, AWE exhaust, intake tube, and RS4 grille at somewhere in the 40K miles. I believe at one of his oil change appointments at ~50k, he had them install the upper pulley and tune for stage 2+. He sold it before it needed another oil change to me and I'm now at 100k.

So, it wasn't my choice; it just made more sense to stick with the same tuner.

This is from a support tech at UniTronic :

We recommend the use of the NGK BKR9EIX gapped to 0.025” on this vehicle using our stage 3 performance software.

[01northernS4]

I purchased my S4 used and the PO had a shop that is a UniTronic vendor to flash it UniTronic stage 1 and install H&R coilovers, AWE exhaust, intake tube, and RS4 grille at somewhere in the 40K miles. I believe at one of his oil change appointments at ~50k, he had them install the upper pulley and tune for stage 2+. He sold it before it needed another oil change to me and I'm now at 100k.

So, it wasn't my choice; it just made more sense to stick with the same tuner.

This is from a support tech at UniTronic :

We recommend the use of the NGK BKR9EIX gapped to 0.025” on this vehicle using our stage 3 performance software.

ahh gotcha, makes sense

I've been running stock 8 heat range ngk gapped at I'm guessing 0.032 stock with no ill effects, clean logs and little to no misfires... wonder if it's worth switching to the 9 heat range at 0.025 gap uni recommends ... she runs strong and clean so what would be the point... could I notice more power?

looking forward to hear how you like the uni dp tune when you've had a chance to ring her out!

Thanks!

[Silver Streakin]

It appears those plugs are a galactic back order everywhere.

UniTronic said it was ok to use the stock plugs, but recommended being safer with 1 step colder and smaller gap.

I have 25k old NGK PFR8S8EG in there right now. I hope FCPEuro has the 9s or can find them. If not, I'll at least replace them so they're fresh and reduce the gap.

It was my daily, but it has only seen about 1k miles in the last 10 months. No rush.

[Silver Streakin]

FCPEURO just confirmed shipment of the NGK BKR9EIX plugs!

I ordered some Sonax alcantara cleaner to get over the $50 free shipping. It could use a good cleaning. I wish I had full leather.

[6SpeedS4]

I just ordered a merc hx. So your saying to install it 180° different than what's instructed? Can you elaborate as to why ?

Sent from my SM-N975U using Tapatalk

[Silver Streakin]

I just ordered a merc hx. So your saying to install it 180° different than what's instructed? Can you elaborate as to why ?

Sent from my SM-N975U using Tapatalk

This won't apply to you with your B8.5 since your S4 has both coolant hoses on the drivers side. A lot of these heat exchangers are setup with both connections on one side. So they connect better to the B8.5

For the B8, it flows from passenger side to drivers side. If we B8 S4 follow the directions, both connectors on the exchanger are on the drivers side. To keep with the intended flow in the exchanger to be in the bottom, a B8 car would run a hose from the passenger side under the exchanger and then need to do a quick 180* to connect it to the bottom connection on the exchanger. MercRacing supplies two 90* connectors to achieve this. Then the upper connector on the exchanger is connected to the drivers side easily.

Personally, I don't like that 180 connection point. It's more free flowing and easier to connect the lower connection if you flip the exchanger around to have the lower connector on the exchanger to be on the passenger side. It lines up perfectly with only about 6-8" of hose with 1 straight connector. If you look at my pic above of the exchanger, you can see the hose to the left of the screen that I added. Again, you don't have to this since this is a B8.

Yes, I still need to run a hose across the exchanger, but, IMO, it's freer flowing from the top (now on passenger side) of the exchanger down to the driver side coolant hose connection with just a straight connector again. Back to the pic, it's the gray plastic covered heater hose. It fits between the exchanger and the a/c condenser. And that's the direction of the coolant flow too. Win-win.

This eliminated using the two 90* connectors (and less clamps, less chance of leaks) to connect the passenger side hose to the lower side of the exchanger on the drivers, if installed following the directions. which to me were written for only the B8.5

I have watched install videos and read write ups where people had the exchanger connections on the driver side and connected the lower side to the drivers side coolant hose on the car. Wrong. That's not the correct path.

Can you send me a Primanti Bros sandwich? I miss Pittsburgh.

[6SpeedS4]

This won't apply to you with your B8.5 since your S4 has both coolant hoses on the drivers side. A lot of these heat exchangers are setup with both connections on one side. So they connect better to the B8.5

For the B8, it flows from passenger side to drivers side. If we B8 S4 follow the directions, both connectors on the exchanger are on the drivers side. To keep with the intended flow in the exchanger to be in the bottom, a B8 car would run a hose from the passenger side under the exchanger and then need to do a quick 180* to connect it to the bottom connection on the exchanger. MercRacing supplies two 90* connectors to achieve this. Then the upper connector on the exchanger is connected to the drivers side easily.

Personally, I don't like that 180 connection point. It's more free flowing and easier to connect the lower connection if you flip the exchanger around to have the lower connector on the exchanger to be on the passenger side. It lines up perfectly with only about 6-8" of hose with 1 straight connector. If you look at my pic above of the exchanger, you can see the hose to the left of the screen that I added. Again, you don't have to this since this is a B8.

Yes, I still need to run a hose across the exchanger, but, IMO, it's freer flowing from the top (now on passenger side) of the exchanger down to the driver side coolant hose connection with just a straight connector again. Back to the pic, it's the gray plastic covered heater hose. It fits between the exchanger and the a/c condenser. And that's the direction of the coolant flow too. Win-win.

This eliminated using the two 90* connectors (and less clamps, less chance of leaks) to connect the passenger side hose to the lower side of the exchanger on the drivers, if installed following the directions. which to me were written for only the B8.5

I have watched install videos and read write ups where people had the exchanger connections on the driver side and connected the lower side to the drivers side coolant hose on the car. Wrong. That's not the correct path.

Can you send me a Primanti Bros sandwich? I miss Pittsburgh.Thanks for the detailed explanation.

I must admit, I haven't been to Primantis in forever!

Sent from my SM-N975U using Tapatalk

[01northernS4]

It appears those plugs are a galactic back order everywhere.

UniTronic said it was ok to use the stock plugs, but recommended being safer with 1 step colder and smaller gap.

I have 25k old NGK PFR8S8EG in there right now. I hope FCPEuro has the 9s or can find them. If not, I'll at least replace them so they're fresh and reduce the gap.

It was my daily, but it has only seen about 1k miles in the last 10 months. No rush.

Yes I just called Unitronic to ask if I can use the 8s since as you said the iridium 9s are on backorder everywhere... but reading on these forums I find many of the notable and respected veteran members saying they aren't great, on all of the top tunes...

Any idea how much of a difference there could be between the 8s and 9s power wise? Unitronic specifically said, if I understood correctly, they pull more heat out of the head?

on stock 8s I see no misfires gapped at stock 0.030/0.032 and it seems to run ok... besides what I would call a very slight, almost imperceptible hesitation low rpms and off the line at times... except when using launch control...

would hate to wait for the 9s gapped at 0.025 and the difference is negligible or worse misfires/problems start as others have said...

[Silver Streakin]

Yes I just called Unitronic to ask if I can use the 8s since as you said the iridium 9s are on backorder everywhere... but reading on these forums I find many of the notable and respected veteran members saying they aren't great...

Any idea how much of a difference there could be between the 8s and 9s power wise? Unitronic specifically said, if I understood correctly, they pull more heat out of the head?

on stock 8s I see no misfires gapped at stock 0.030/0.032 and it seems to run ok... besides what I would call a very slight, almost imperceptible hesitation low rpms and off the line at times... except when using launch control...

would hate to wait for the 9s gapped at 0.025 and the difference is negligible or worse misfires/problems start as others have said...

I am only following what UniTronic said to use, which makes sense to go colder. I did with my stage 3 B5.

I believe it's only a heat issue, not going to change power. It would be negligible. If anything, less power with a smaller gap recommendation. But you don't want misfires.

FCPEuro has them. They just shipped them to me.

Any links to threads about them not being good to use?

I've read more about tuners recommendation of using them.

I can see changing them more often, but they should still be a great plug. This could be another one of those things like engine oil how one car likes one over the other.

I plan to drive it with 8s and then change to the 9s to see if there is any difference. I doubt it. Just pulling heat out better, IMO.

[01northernS4]

I am only following what UniTronic said to use, which makes sense to go colder. I did with my stage 3 B5.

I believe it's only a heat issue, not going to change power. It would be negligible. If anything, less power with a smaller gap recommendation. But you don't want misfires.

FCPEuro has them. They just shipped them to me.

Any links to threads about them not being good to use?

I've read more about tuners recommendation of using them.

I can see changing them more often, but they should still be a great plug. This could be another one of those things like engine oil how one car likes one over the other.

I plan to drive it with 8s and then change to the 9s to see if there is any difference. I doubt it. Just pulling heat out better, IMO.

agreed... what are the main benefits of pulling the heat out better? Lower IATs? Better engine reliability?

honestly, a bunch of threads that I specifically saw the most respected and fastest guys recommend against, iirc, like loe and mattys4... let me see if I can dig up some links as their posts were buried in those threads and I'd have to re-read all of them... just posted another thread to try and consolidate the info there

you'll have to vote the 9s in that poll as will I! lol

[01northernS4]

I purchased my S4 used and the PO had a shop that is a UniTronic vendor to flash it UniTronic stage 1 and install H&R coilovers, AWE exhaust, intake tube, and RS4 grille at somewhere in the 40K miles. I believe at one of his oil change appointments at ~50k, he had them install the upper pulley and tune for stage 2+. He sold it before it needed another oil change to me and I'm now at 100k.

So, it wasn't my choice; it just made more sense to stick with the same tuner.

This is from a support tech at UniTronic :

We recommend the use of the NGK BKR9EIX gapped to 0.025” on this vehicle using our stage 3 performance software.

Unitronic advises 0.028"... call them yourself to confirm before you install those 9s... they still recommend the ngk 9 iridiums