[Bimmer 808]

Haven't seen a lot of info on the new VRSF HD so here's my contribution. I just replaced the original VRSF 7in with the HD. The original wasn't cutting it and heat soaking badly at No Fly Zone. I would not recommend this FMIC for back to back runs.

Here are some pics comparing the original to the HD. You can definitely see the difference in fin density between the two. The original fin gaps are YUGE compared with the HD. Also despite being the same dimensions the HD is 4lbs heavier than the original, presumably from the extra material stuffed in there.

I'll be testing the HD out at NFZ AZ this weekend and report back my results with logs.

[Chris@VargasTurboTech]

Good stuff! Any reason you went with that instead of the 7.5" race version? I look forward to seeing how the HD does at NFZ. We won't be running but I may come out and say hi to a few people and check out the action.

[Bimmer 808]

Originally Posted by Chris@VargasTurboTech

Good stuff! Any reason you went with that instead of the 7.5" race version? I look forward to seeing how the HD does at NFZ. We won't be running but I may come out and say hi to a few people and check out the action.

Hey Chris, couple reasons. First is I'm still running stock turbos and I'm worried about pressure drop. Second is I'm lazy and didn't feel like cutting more, just switch out real quick. Hopefully we'll see some improvement in IATs.

[FEDE/E92]

Subscribed

[ritzzzzzwik]

Subed!

[Tiago@VRSF]

We generally recommend the new 7.5" race core for folks interested in any sort of racing but the 7" HD is a great compromise, especially on the stock turbos. Be sure to post logs if you have them available

[FEDE/E92]

Originally Posted by Tiago@VRSF

We generally recommend the new 7.5" race core for folks interested in any sort of racing but the 7" HD is a great compromise, especially on the stock turbos. Be sure to post logs if you have them available

What difference should we see between both of this?

[Tiago@VRSF]

The 7.5" race intercooler is twice as large internally as the 7". It's rated for over 1000whp and it's recommended for anyone looking to push the limits of stock frame turbos as well as individuals who switch to a single turbo setup.

The standard 7" works well on stock turbos on street duty but the 7" HD is ideal for both stock and upgraded turbos on both the street and the track. If you're going to test the limits of the car on a half mile stretch, the race core is going to be your best bet when fighting rising intake temps.

[mike@x-ph.com]

Thank you for the pictures, the 7" high density is a big improvement over the standard core

[Jeff@TopGearSolutions]

Originally Posted by Bimmer 808

Haven't seen a lot of info on the new VRSF HD so here's my contribution. I just replaced the original VRSF 7in with the HD. The original wasn't cutting it and heat soaking badly at No Fly Zone. I would not recommend this FMIC for back to back runs.

Here are some pics comparing the original to the HD. You can definitely see the difference in fin density between the two. The original fin gaps are YUGE compared with the HD. Also despite being the same dimensions the HD is 4lbs heavier than the original, presumably from the extra material stuffed in there.

I'll be testing the HD out at NFZ AZ this weekend and report back my results with logs.

Really like the HD core from VRSF. You should have great results.

[drpeckr]

I am running Pure S2 snails and I just switched from the VRSF 5" stepped to the VRSF 7" HD.. I could have gone with the 7.5" race, but it's my DD and from talking to the vendor I bought it from, since I don't plan on any extended racing (mostly just drag type runs from time to time) the 7" HD would be the better option. I can tell you that my IATs on longer runs are SOOOOO much better (no meth here), ie a 3rd-4th gear pull used to hit up to ~150 degrees now never breaks 110 on my 91 octane tune (california urine gas) (under similar ambient). And the IAT temp drops quickly once I let off.. I have an e40 tune as well but I haven't had a chance to try that out with the new FMIC as we're still finishing my 91 octane tune..

With how much of the non-stepped FMIC is covered by my bumper I'm wondering if I really need to get an M-Sport type bumper so I don't get too much heat soak..

I hope I made a good decision...

[mike@x-ph.com]

Originally Posted by drpeckr

I am running Pure S2 snails and I just switched from the VRSF 5" stepped to the VRSF 7" HD.. I could have gone with the 7.5" race, but it's my DD and from talking to the vendor I bought it from, since I don't plan on any extended racing (mostly just drag type runs from time to time) the 7" HD would be the better option. I can tell you that my IATs on longer runs are SOOOOO much better (no meth here), ie a 3rd-4th gear pull used to hit up to ~150 degrees now never breaks 110 on my 91 octane tune (california urine gas) (under similar ambient). And the IAT temp drops quickly once I let off.. I have an e40 tune as well but I haven't had a chance to try that out with the new FMIC as we're still finishing my 91 octane tune..

With how much of the non-stepped FMIC is covered by my bumper I'm wondering if I really need to get an M-Sport type bumper so I don't get too much heat soak..

I hope I made a good decision...

You definitely made a good decision

[BKBMW335I]

Originally Posted by mike@x-ph.com

You definitely made a good decision

He did, but not on his forum name, lol.........j/k!!

[drpeckr]

lol yeah the name is something I've been using as a moniker for many a year, it started because I had a hat that was burgundy and in the Dr Pepper font said "Dr Pecker" (I lost it in a mosh pit, the only time I've ever been knocked down in one.. was during Thunderkiss '65 by White Zombie @ Arco Arena in Sacramento circa 1996!).. since I'm such a d!ck, I ran with it.. "asshole" just didn't have the same ring to it and alot of places where I use a username won't let me use "bad" words.. peckr isn't a bad word apparently

hehe

[mike@x-ph.com]

Originally Posted by BKBMW335I

He did, but not on his forum name, lol.........j/k!!

[Tiago@VRSF]

Glad to hear you're enjoying it

[Bimmer 808]

Here are the results of my intercooler comparison from recent No Fly Zones.

Bottom line up front, yes the 7in HD is better than the original.

How much better? I will attempt to quantify. These are just basic measurements and I don't claim to be a scientist. If anyone else has a better way to compare the two than by all means please contribute, the raw data is all there.

Here are the logs from 8 Oct 2016 with VRSF original:

http://www.datazap.me/u/lumikuke/log...=1534.38&hg=17

http://www.datazap.me/u/lumikuke/log...=4215.61&hg=17

http://www.datazap.me/u/lumikuke/log...x=293.29&hg=17

http://www.datazap.me/u/lumikuke/log...=1109.18&hg=17

http://www.datazap.me/u/lumikuke/log...=2360.08&hg=17

Here are logs from 11 Mar 2017 with VRSF HD:

http://www.datazap.me/u/lumikuke/nfz...x=343.30&hg=16

http://www.datazap.me/u/lumikuke/nfz...x=570.17&hg=16

http://www.datazap.me/u/lumikuke/nfz...=1644.10&hg=16

http://www.datazap.me/u/lumikuke/nfz...x=374.44&hg=16

http://www.datazap.me/u/lumikuke/nfz...x=325.93&hg=16

http://www.datazap.me/u/lumikuke/nfz...x=473.75&hg=16

Both days were pretty hot, around 89 degrees. You can clearly see the highest IATs achieved at the end of runs for the original were in the 180s, vice 150s for the HD.

Comparing the highest temperatures achieved from both days, the HD was about 15% cooler than the original at peak IAT.

160/187 = 0.85, or 15%

There was also improvement in temperature delta for each run. Taking the difference in temperature between the highest and lowest point of each run you get an average temperature change of 43 degrees for the original vs 22 degrees for the HD. That is a 49% improvement in temperature gradation.

Original: 43, 38, 40, 44, 50 = 43
HD: 22, 20, 18, 25, 18, 29 = 22

22/43 = 0.51, or 49%

So how did this translate to the track? No change. I still trapped 143-144 mph consistently despite running the VRSF HD with lower IATs.

Final thoughts:
The extra money for the VRSF HD is worth it. Despite no change in trap speeds, there is more peace of mind running the HD with the lower IATs it provides. I'm still not satisfied with the peak temperatures I am seeing in between runs. There is clearly heat soak going on with the HD, albeit to a much lesser degree than the original. The change in temperature gradation is much improved.

I'll be upgrading to stage 3 twins and inlets soon, so we'll see how well the HD performs then. I expect IATs to decrease with the bigger turbos and less restriction.

If anyone runs the 7.5 in on stock turbos I'd like to see a comparison.

Thanks

[arhoads335i]

If you mind me asking what kind of front bumper do you run? That could play into it!

[Antetokounmpo]

Originally Posted by arhoads335i

If you mind me asking what kind of front bumper do you run? That could play into it!

Sig says e90 m-sport.

[Tiago@VRSF]

Thanks for posting the logs!

I don't think you'll find any intercooler in the 7" range that's capable of only increasing temps 23 degrees through a 2-5 gear pull although these are the highest temps I've seen so far with this intercooler. For example here's an independent log provided recently by a member of this forum who seems to be running the same amount of boost as you. 12 degree rise, 99f at 2k rpm in 3rd to 111f at 6.1k rpm in 5th.



The heatsoaking issue when doing quick subsequent drag pulls is going to be a constant issue with all intercoolers. Unless there's ambient air flowing through the core, you're not going to be able to cool it down in between quick runs.

[hellokitty]

Tiago: How would the 7.5" race do on maxed out stock turbos?

[Tiago@VRSF]

You'd have a very hard time increasing the intake temps more than 4-5 degrees on a 2-5 gear pull with the race core on maxed out stock turbos. The race core is almost double the capacity of the 7" with the same incredibly dense fin pack.