74mm Throttle Body vs 82mm Throttle Body Testing...

[bhvrdr]

First, let me take the time to once again thank Bryan at Euromodsperformance.com for the awesome experience purchasing the IABED throttle body harness and adapter. Bryan kept me informed every step of the way and was overwhelmingly responsive, professional and polite throughout the process.

I was able to take advantage of the 10% off sale and purchased the harness for $270 and the adapter for $180. This is all that is needed. I already had a 74mm Bosch throttle body sitting around from my 997. This TB is on a ton of Porsches and can be found in great shape on ebay too for around $50. I also had the 82mm Bosch Throttle body available which is a common 997 Porsche upgrade. This is usually found brand new for approximately $140


Thank you also to Issam Abed for taking the initiative to create this harness given us a plug and play solution for upgrading TB sizes.



CONDITIONS:

All testing was performed the same day and same hour on the same stretch of road running the same direction. The fuel was the same for both runs. The starting intake air temps were closely matched so IAT related timing changes were not confounding.


74mm Runs DA: 3:03pm - 71f

82mm Runs DA: 3:48pm - 70f

Ultimately its about as well controlled of a test session as you can get without having a climate controlled test cell.

The following was the vehicle setup for all runs:
2013 Audi S5, DSG with Unitronic Stage 3 file that allows up to 26 degrees timing and requests 2450mbar boost. 200mm KI pulley was installed with stock SC pulley. Divorced Revo charge cooler installed. Exhaust is stock. The air intake was identical for each run with the exception of the size of inlet to t the throttle body.



TEST VARIABLES:
I tested the following setups:


1. 74mm Throttle body p/n: 99760511501 for 74mm throttle body

2. 82mm Throttle body p/n 99760511601 for 82mm throttle body



RESULTS:

Here is the log of two 74mm runs with cool down in between to stabilize and equalize intake air temps across all sessions and runs…

https://drive.google.com/open?id=1Ke...6SktLBgOdzsz2K

Here is the log of two 82mm runs with cool down in between to stabilize and equalize intake air temps across all sessions and runs…

https://drive.google.com/open?id=1O3...9tUOwJgkrLxxHe

another 2 runs with the 82mm throttle body...

https://drive.google.com/open?id=1Bi...fI7-Y2jZtUdxe1


VIRTUAL DYNO -




DISCUSSION:

Performance is a wash between both options with this vehicle configuration. No significant gains or losses were observed.

Also important to keep in mind that this testing was performed on a car with stock blower without ported inlet and on a relatively modest dual pulley ratio of only 3.17. Further testing is to be performed on a ported blower and higher pulley ratios.

Driveability has been the same as stock thus far. No issues noted. No perceivable difference noted.


PHOTOS:

[bhvrdr]

Would anyone be willing to make some charts out of the data for me? Ill owe you one :)
Mike

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[evil35r]

Both look pretty much the same. The 74 you get slightly less boost but more engine tq if I’m reading it correctly. Not much of a difference

[bhvrdr]

I think i need to virtual dyno the data but my virtual dyno program gives me nothing but error codes. I suck at it

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[evil35r]

Doing it for you now

[evil35r]

[IMG][/IMG]


Very negligible

[vpls4]

Thank you guys!

This confirms what Tony@EPL also found doesn't it?

In our testing... when staying with a conservative size upgrade, there was no lose in torque (in fact there were significant gains). Then going too big, there's no additional peak horse power gains but there as low end losses (pretty significant if you go too big). We tested several sizes btw.

[bhvrdr]

There were no losses in torque but no gains either. It confirms part of what he saw. I'd say its a wash for now. Not surprising with a non ported blower and only 3.17. I'll test again on parted blower and likely up to 3.55 pulley ratio.

Hopefully we'll see even more testing soon as a little birdie told me a certain tuner now has one ready to go on their shop S4 for some exhaustive testing in their MAHA dyno chamber.

mike

[Morritse]

Yup. A wash. Any differences you're seeing are well within margin of error.

There's a reason issam and EPL are pushing the 74mm TB.

[evil35r]

Agree but with a larger ratio and ported blower there may be gains but my guess is still minimal at best 5-10 maybe.

[ModItNow]

Nice Mike! Really looking forward to seeing the data with ported blower and higher PR.

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[brs2c]

As I posted in another thread- Going to be very little difference, if the SC inlet is stock diameter. You can’t take advantage of the 82mm, unless you either have the blower inlet ported out to almost no metal left (76-78 opening), OR cut the inlet off and weld a flange on at the wider point of the inlet (80mm opening, and the safer option). Do either of these, and you will see a difference over the 74mm.


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[bhvrdr]

[IMG][url=https://ibb.co/h7CY84R][img]https://i.ibb.co/0DQsJ6j/0-D63-AECA-DB9-F-4-EC1-96-D5-E4822763-


Very negligible

Thanks for the graphs!


Yeah i agree for my mods 74mm makes sense. You can find the tb used for change and the 74mm adapter plate seems like it provides a better seal to the throttle body.

You can see on the 82mm adapter the seal is broken up by the bolts from the adapter to supercharger. Theres no ring of clean smooth surface around the tb where it mates up to the adapter.

Mike

[proxemus]

As I posted in another thread- Going to be very little difference, if the SC inlet is stock diameter. You can’t take advantage of the 82mm, unless you either have the blower inlet ported out to almost no metal left (76-78 opening), OR cut the inlet off and weld a flange on at the wider point of the inlet (80mm opening, and the safer option). Do either of these, and you will see a difference over the 74mm.


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If someone is willing to mail me an empty core I will gladly cut it off and weld one on for science free of charge.

[lopott]

+2 in dealing with Bryan at euromods. great experience.

[k186]

Couple cleaner vdyno files for comparison:

First 74mm run vs. First 82mm run in the first file:




First 74mm vs Second 82mm run in first file:



In both cases, it looks like 5-10HP increase across most of the powerband. I think the comparison evil35r (lmk if I'm wrong) posted was based on the later log with 1-2 degree higher starting / ending IATs relative to the 74mm logs. I'd say....cautiously optimistic?

Edit: re-uploaded vdynos with DSG specs (somehow I ran it under manual)

[bhvrdr]

Couple cleaner vdyno files for comparison:

First 74mm run vs. First 82mm run in the first file:

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First 74mm vs Second 82mm run in first file:
[g[/IMG]


In both cases, it looks like 5-10HP increase across most of the powerband. I think the comparison evil35r (lmk if I'm wrong) posted was based on the later log with 1-2 degree higher starting / ending IATs relative to the 74mm logs. I'd say....cautiously optimistic?

Edit: re-uploaded vdynos with DSG specs (somehow I ran it under manual)

Hey, thank you so much yet again! It may not seem like much but I go nuts trying to get my virtual dyno to work, lol. I had mistakenly only posted that first, single 82mm run. I meant to post the 82mm session that had multiple pulls.

Yeah, its possible there is a little something. At the very least I'm glad there appears to be no losses at all. Perhaps the more we go up in pulley ratio the more we can see.

Thanks again
mike

[evil35r]

I used the first set of runs in both logs when he first posted them. Yea I agree if anything prob 5-10 still a wash now if I were to do it all over again would I get the 82 now that I am ported and have a larger ratio prob but will I stay where I’m at till I’m bored and wanna switch and sell my 74 maybe lol

[bhvrdr]

So my concerns about the design of the 82mm may be well founded.

Look here at the 82mm tb adapter and see the sunken bolt holes that secure the adapter to the supercharger span the entire width of the adapter plate.... meaning there is no uninterrupted flat surface to mate to the throttle body...




Here on the 74mm tb adapter see there is a flat full circle of metal that can mate and seal to the tb...




Sure enough im getting p2279 air leak codes despite torquing perfectly again now to even 15 lbs


Mike



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[evil35r]

Mike you’ll get a air leak code it’s tune related... I don’t think you have a air leak. Anyways I used gasket maker in both sides.

[bhvrdr]

Mike you’ll get a air leak code it’s tune related... I don’t think you have a air leak. Anyways I used gasket maker in both sides.

Never gotvan air leak code on the 74mm and i beat the piss out of it. Look at the imprint in the gasket. I think i need to use something else to seal it no?

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[evil35r]

Gotcha, yea I would just forgo the gasket and use gasket maker...

[bhvrdr]

Heres the 74mm seal. Theres space to seal between the bolt hole and lip

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[evil35r]

Concur

[bhvrdr]

Concur

Darn. I was hoping youd tell me why i was being stupid lol

[evil35r]

Lmao you’re being stupid 🤣

[j23a45m]

Mike do you know the out side bolt specs? Looking for them and didn’t know what ones to get!

[TSherk]

Great comparison mike. Glad to see you back in a 3.0T
Sorry if it’s off topic but how would you describe the differences in the b9 compared to the b8.5

[MercRacing]

Hello. Upgrading the TB will net no significant gains if the air is being choked at the intake of the supercharger. you must allow all the new air to feed to the blower unrestricted. :)

what you may get is a slight bump in the chart because the TB is opening to more air sooner.