Reading thread...trying to learn...head spinning...time for a beer...

 

Another data point from the drive home. Way more traffic, lots of heat soak.
3000rpm, 5th gear steady driving for about a mile:
ambient 62F, core-in 216F, core-out 101F TE=(216-101)/(216-62) =~ 76% Still not bad under pretty nasty evening commuter conditions. Of course, in stop-go traffic I saw the IATs rise to 130F--that's some hot air entering the cylinders.
I should get my new M7 boots in a few days, so will wait to put them on, and undo the VGS at the same time. Till then I'll keep logging the casual observations.

 

Again, this morning, a constant 3000rpm 6th gear (70mph) run on the freeway. After a couple of minutes the IC settled down to produce 88% efficiency (200-60)/(200-40). I seem to be sitting at about 20F above ambient at cruise. I presume this is about normal? Only Sid gets lower due to his water/meth injection!!

 

In those conditions mine varies from 12-15º with the JS scoop on. With a stock scoop it's higher. Like the graph I posted yesterday.


Can't find my spreadsheet of data with the JS scoop What a doofus.

 

I think that's in a fairly typical range. This morning on the way to work on I-65 it eventually settled in to around an 8-10degF difference between ambient and the stock IAT sensor reading (via Scangauge hookup to the OBDII port).

That's at 70-73mph actual (not the speedo reading) and 3000rpm in 6th. No wind to speak of today. 2003 MCS, DT bypass valve, 19%, DFIC/scoop currently installed.

FYI, the GRS with stock scoop under the same conditions did about the same prior to the DTBPV.

Scott
90SM

 

Actually, this is a bit on the high side for outlet IC temps. Here is the data I posted previously, where the outlet temps are 10-15 F over ambient, which on this day ranged from 60 to 62 F. Measurements taken with 19% pulley, HAI with heat shield, VGS, stock IC (insulated), new diverter, and opened up hood scoop (stock).

 

So how would you thermally isolate thermocouples that would fit in the 1/8"NPT bungs in the DFIC?

 

you want a Tc that is nude (fast response) and is isolated with a temp range appropriate potting compound. Also, having the SS sheath longer (it has very poor thermal conductivity) helps, so coming in from the side with a longer probe into the middle where the temps is measured, helps as well. THe smaller the diameter Tc wire, the less the effects will be as the temp of the junction will be more directly effected by air changes than the wall temp (smaller diameter conduction path for heat along the wire). For exhaust work, you can go too small (I used some in my job that were made with wire less than 1 thousanth of an inch in diameter to prevent thermal leaks) and cook them.

Alother thing to look at is jacketed probes have more of an issue with thermal leaks, and for the short term just use a bunch of winds of thick teflon tape. It will help. Also, jacketed probes take longer to stabilize (the time constant for the temp part of the T-Map sensor is 10 seconds!) so keep that in mind when you measure transients.

Matt

But I'd say who really cares? Probes alone for exhaust gasses in Jeg's are about $70 each! So just say ef it, and look at changes. While you won't get absolute numbers (or may not, it all depends), all trends will show the proper direction and close to the correct magnatude....

Matt

 

That's the way I look at it too...Afterall, we're not flying space shuttles...it's nice eye candy too

 

Sid's right! It *is* the VGS! Did the mod this morning, and here are the numbers:

3000rpm, 6th gear, 70mph constant freeway driving about 5 miles

ambient 56F, inlet 160F, outlet 60F
TE = (160-80)/(160-56) = 77%

another interesting observation: after 3 minutes in a drive through line, the outlet temp was 160F. After 1 mile down an uninterupted road at 50mph, the temp had dropped to 96F! That's incredible.

Me likey my air intake path. No to test a new air filter...

cheers,

 

Just waking-up, so please forgive me if wrong, but shouldn't TE be like 96%?

I think you meant to use 60 where you have 80 here:

ambient 56F, inlet 160F, outlet 60F
TE = (160-80)/(160-56) = 77%

The doc's around here are appreciated! Thank you for more data, further confirming Sid's comments from quite a while ago...

 

Sorry, the calc is right, my statement of the outlet is wrong: 80F not 60F.
This TE is closer to those reported by inimmini above and appear to be in the range reported for larger ICs like the GTT and GRS.
Oh well...

 

Bingo, all clear now... Good info on the VGS.

I feel (from my data-logging) that the real benefit of these type of IC's is seen at WOT, increasing RPM's to the limit, and higher speed.... lower peak IAT's when really hammering it.

 

Tony: I have had a couple of pms with Don (dmh) who is not at all keen on any of the available ICs on the race track. The DFIC he tested apparently fell off the boots! Those of us using silicon boots don't have that problem, fortunately.
Anyway, I agree with you that the benefit of the DFIC may be seen in other areas than just pure highway cruising TE. I am impressed that at WOT, I only saw 130F max inlet temps. I am also impressed by the ability to lower inlet temps from a stand still, or prolonged idle situation.

btw, I insulated the probes from the IC body with more rubber, hopefully to prevent thermal transfer to the probes under heat soak conditions. The probes don't actually touch the IC directly anymore.

cheers,

 

Finally...vindicated

Thanks for the confirmation Phil

Just got back from a day long cruise and Msfitoy's rippin good! This just makes my day

Sid

 

I've had zero problems with the stock boots, but then I prepp'd them first by filing the clamps down a tad so they would cinch-up more sunggly; and they do. I don't track my MCS though... but it sees some pretty heavy action on canyon roads...

Max IAT's with my modified GRS were seen at max RPM's... with the DFIC, max IAT's (lower than the GRS) were not seen at the highest RPM's... revealing, I feel, the DFIC's ability to more effectively get quantities of ambient air through the core...

Good job on insulating the probes! Please share a photo or two, when time permits... Thank you for your efforts.

 

Where's the before and after comparison?

 

FWI, a stock intercooler with NO diverter and NO hoodscoop does a REALLY poor job of cooling.

It was a short one-time-only drive and not an attempt to improve anything. The hole in the hood is really big though!

Scott
90SM

 

I tested that configuration and the IAT shot up to near 300F with every step of the go pedal...don't do it...

 

MSFITOY,

It wasn't an intentional experiment, it was just a way to get home! I babied it all the way in light traffic, trying to keep from going into boost. Despite that, it still crept up to around 155F intake air temp in 60F ambient.

Just throwing another (borderline worthless) data point out there, just because.

The diverter and scoop are now installed. They were off because we were still waiting for the epoxy on the threaded studs on the scoop to dry after being glued back in place. It took longer than anticipated.

Scott
90SM

 

I see...

 

I did a little run the night before last, Amb. temp was 65F I found a clear spot in traffic for a bit and was able to run 3k @ ~70mph for about 1 minute. The scan tool read a consistent 75F IAT. I don't have any idea what the pre IC temp was but it was probably less that you guys see as I haven't installed my pulleys yet. This was with a bone stock car.

 

Before: (with VGS) :TE = (200-60)/(200-40)
After: (without VGS) : TE = (160-80)/(160-56)

If course, you could say that the before TE was higher, which it is, but the after TE leaves me with a lower IAT relative to ambient. Doesn't it?
Also, with the VGS, I was seeing 200F IC-in temps constantly, whereas I was seeing 30-40F lower IATs without the VGS.
Ultimately, I'm inclined to go with the system that produces the lowest IATs for more day to day conditions.

btw, I don't have a scanning tool, but I'm suspicous of any tool that shows "consisent" temps: the instrument that Sid and I are using is designed by Davtron who makes airplane gauges. I talked with the rep on Wed. and he told me quite a bit about the design of the gauge and the probes. I have another call in next week for more information, but they calibrate to 1% error using the probes that the kit ships with. Apparently the gauge calibration is software controlled, but this is what I need to find out more about. Anyway, Im pretty confident in the instrument.

 

The consistent 65/75F I saw was only seen while I held it at 3k & 70mph. It was all over the place while working through traffic.

 

Wish I had your gauges.
Mine are cheap and slow but are accurate compared to a pretty expensive pyrometer.

I'll have to test the VGS thing too. I have very good temps now. If they get better without the VGS then my TE should get slightly better as well.

Now that you have your gauges going will you see what a difference closing off the CAI air?

Thanks