DCIs vs stock and modified air boxes

[B21]

For those not following the other thread on airbox discussions here’s the abridged version..

All on an E89 35is running TTE500 turbos on 99 RON fuel..

So here’s the answer to ‘well how does it compare to DCIs?’…

Today’s dyno runs..

The chart with 3 lines is tune V17 (iteration 19) which has been tweaked to reduce timing corrections and improve spool..peak power is slightly down on the earlier v13+..torque up..two versions one with the Mr.5 mod and one using DCIs…compared to v13+ with the Mr.5 mod…

The chart with 5 lines is version 6 of the tune ..revisited twice..once with a Mr.5 mod and one with DCIs

[KennyP]

Hmm interesting...

So DCI has higher peak torgue and is better in midrange rpm and Mr 5 mod is better in the higher rpm?
So basically depends on what your needs are isnt it?
Better midrange is actually good, because you mostly live in that rpm range and you dont really redline your car everyday or every drive... for street car that is.

I had Hondata Flashpro on my FN2 Type R with a Gruppe N map on it... It didnt really give much peak horsepower (NA engine life), few hp maybe because of the raised rpm limiter, but lowering Vtec high profile cam switching from 5600rpm to 3800rpm totally transformed it... Lot more power in the midrange where you mainly are most of the driving...

My question is why does DCI fall short at high rpm? Really temps come so much into play? It shouldnt be restrictive... i would think mr5 is more restrictive...

[Hejnfelt]

Since this is a Dyno run, probably temps due to poor airflow. And consider also that B21 is running Wagner EVO3, if this would be anything less, difference might be significantly bigger.

In attached pictures you see the air density on Y axis at temp on X axis. Lines are relative humidity. Notice that there's a significant difference between 25C and 60C. On stock FMIC it's not uncommon to go from 30C to 60C or more intake temps on a single pull. Especially if you're running something mild like MHD stage 1.

The massive drop in air density will obviously lead to power losses.

Hot air is a double whammy as it holds much more humidity and will literally rob humidity from cold air around it and this decreases air density even further as you see in the graphs.

[Hejnfelt]

And adding to this, turbocharged cars in particular are notorious for having higher under hood temperatures than regular cars. Granted, on the Z4 N54 engine the turbos are on the other side of the engine and there isn't much data available, but I do know that in recent 10 years the plastics that are used under the hood in most cars were uprated in their material property requirements from 125C to 175-200C in most OEM applications specifically due to the commonality of turbochargers these days. Consider that most engines operating temps are around 100C and exhaust manifolds easily hit 350C and you're really cooking the air in the engine bay and relative to the graph above the difference in air density to "normal" outside 25-30C is crazy once we pass 60C.

[KennyP]

i finally installed that EVO1 intercooler i got from B21 today... After install went to a longer testing run...
At first i kept cobb stage 1 mapping and monitored the live data on the accessport display.... then mid drive stopped and loaded up stage1+FMIC mapping and continued.
Peak PSI registered was 16.6 PSI on stage1 and 17.7 on stage1+ though once it registered 19.2 on stage 1+ aswell... but that was more like a freak occurance...

Im sure datalogs would be better, but i didnt do that. Just had live gauges with min max for each gauge on the screen.

With both maps while driving i saw IAT staying at 35-38 range. And i tried to get them up. Back to back accelerations in town and also on country roads.

Max IAT accessport ever registered was 48C during longer idling but right away when i moved it was back to 35-38 range. While driving i never saw that.
Outside temp was 19C at the time according to car display.

Oiltemp went a bit higher than it usually stays at.. 120C.

So even in 30C weather IAT should not go past 50C (38+11) with this intercooler even if i drive like a hooligan. Quite happy with that..

With stock intercooler i have seen IAT rising over 70C.
So for me this IAT issue has been basically solved. Until i decide to try to up
the power again...

[Hejnfelt]

wow, 70... That's nuts. Glad you got those sorted.

[KennyP]

Yes it can happen... Look at these videos:

https://www.youtube.com/watch?v=eAGK2J1Ctwg

They got 74C with stock intercooler.. though those guys are based in Australia, so probably quite warm weather there...
So im having basically the same results...

They also have a DCI testing video before the intercooler install:
https://www.youtube.com/watch?v=wN2Sv0TsAa4

Good channel to watch if you like N54s...

[B21]

You could increase the size of the Mr.5 tubing if it was felt that the mod was still not supplying enough air..

The mid range torque increase on DCIs is noticeable across all tests..

I assume that in the confines of the airbox the pulses emanating from the stop start nature of airflow in an engine combine to create destructive interference effects reducing flow..in an engine bay these pulses are fed back to each DCI and then vented into the big engine bay space.

In this case with 750nm of torque the ‘benefit’ of the extra torque from DCIs is not really required …

For asthetic reasons, filtration and noise issues I’ll stick with Mr.5

The chief tuner of the company ran the dyno yesterday..they’ve tunes hundreds of N54s, N55s and now B58s.

He did say that despite his own scepticism initially DCIs do do consistently well..unlike many other aftermarket airbox designs..and he did say heat soak is obvious in bad stop start traffic but disappeares after a few seconds once moving..

Anyway nothing like some factual data.

Of course what we can see is the lower the tune the less impact DCIs have over a stock system.

[Hejnfelt]

Continuing this topic, I wonder whether the whole "engine bay" vs intake heat soak is fixable simply with active fans venting fresh air into the engine bay. When do the stock radiator fans activate?

[B21]

Originally Posted by Hejnfelt

Continuing this topic, I wonder whether the whole "engine bay" vs intake heat soak is fixable simply with active fans venting fresh air into the engine bay. When do the stock radiator fans activate?

The fans activate at various times depending on the ‘mode’ of the cooling system, this is determined by the DME based on what throttle setting and other variables…

IMHO…you either roll with it or like some designs fabricate a heat shield between the DCIs and the engine bay..I’m not sure in that case whether they then fall victim to the same interference effects you see in the airbox…I’m certainly not going to buy a set and try it out..

[KennyP]

With DCI the original ducting for the oem airbox still stays there and feeds air to the intake area... I have considered adding intake scoops behind the front grill from where this ducting takes air from.... that may aid feeding colder air to the intakes... Some sort of heatshield wouldnt be a bad idea aswell...


something like that:
https://www.amazon.com/AVT-Intake-Sc.../dp/B07N99VC6D

[B21]

Originally Posted by KennyP

With DCI the original ducting for the oem airbox still stays there and feeds air to the intake area... I have considered adding intake scoops behind the front grill from where this ducting takes air from.... that may aid feeding colder air to the intakes... Some sort of heatshield wouldnt be a bad idea aswell...


something like that:
https://www.amazon.com/AVT-Intake-Sc.../dp/B07N99VC6D

I think the front area is all taken for by the existing radiator /air con..you could use the faux duct on the opposite side to the oil cooler and route something up there..its all very tight..I suspect the remenants of the air duct is largely placebo as at speed huge volumes of air come though the rad area into the engine bay anyway..

Its one area where its difficult on a dyno to simulate real road conditions..

FWIW I suspect that when you start going really fast ..100 mph+ the standard cold air intake into the airbox would enjoy quite a pronounced ram effect that is missing with DCIs..

Certainly on some piston aircraft this technique was used and was said to be worth about 20+ BHP in 180 bhp..

Only be doing some 150-250 kph dashes will you ever know..

[Hejnfelt]

The ram effect is used on pretty much all high performance motorcycles today. The challenge is the tuning of the velocity stacks to the throttle bodies. Not an issue with turbos.

Continuing the thread on the topic of the airbox and filters, I guess the question of air is really only a topic once we're making 400+hp as the stock equipment wasn't really made for it. A lot has happened in the past 15 years on air box and filter designs and if you really want to run 500+ wheel hp on a daily basis and have a reliable engine then clean air is essential.

It would be interesting to test out something off shelf that connects to the OEM duct system. E.g. the Maserati MC20 dual airboxes with multitube UFI filters. That setup is made for 600+ hp all day and would bolt onto the turbo intakes and could be easily routed up to the stock intake duct.



Instead of buying 2x400eur airboxes plus filters, it would be possible to CAD up a design that fits the multitube filters and otherwise bolts up correctly. I think it would fit in the space avaiable and those UFI synthetic filters are amazing. There's a reason Porsche and Mercedes AMG runs them.

[B21]

Looks very sexy..where do you buy the tubes on the open market..its gonna need more than some 50mm waste pipe fixings to sort that one out..

[Hejnfelt]

Eurospares has it as OEM kit.

[B21]

Hmmhh

So it’s pretty expensive and can’t see how you are going to get that into the E89 engine bay…

Look forward to your 3D solution..

[Hejnfelt]

It's gonna be a little while. Probably in the darkest months of winter when everything is snowed over and there's nothing else to do

[AmuroRay]

Evo 1 is too small of an intercooler...

[KennyP]

Originally Posted by AmuroRay

Evo 1 is too small of an intercooler...

Depends on the application... for a bolt on car or stock car with a tune it seems totally enough... EVO1 also seems better than similarly sized chinese ebay intercoolers. Its not just size with these... flow, fin design etc matters aswell.
Tbh if i did not care about the money at all, then EVO2 kit would have been a bit better... but it costs over a 1000 eur. and in longterm if i happened to upgrade turbos(for example when they finally fail) then i would have to take it off, sell it to someone at a huge discount and buy an even bigger one... evo3 or vrsf 7.5 inch etc...

So my plan was not to invest a lot into a bolton car intercooler that gets replaced with a bigger one at some point probably anyway. Thats why i was looking for a used one from someone who was at the point of upgrading turbos and switching intercoolers.

Of cource someone would think that "hei, then just buy the biggest intercooler right away." But that isnt good for a stage1 or stage2 car - it would introduce turbo lag and so on.. also big intercoolers weigh a lot.

[B21]

For a 400 BHP running 18 psi boost tune on stock turbos on a Northern European climate the Evo 1 is more than adequate..as was suggested it’s much more than just simple frontal area..

[AmuroRay]

Originally Posted by KennyP

Depends on the application... for a bolt on car or stock car with a tune it seems totally enough... EVO1 also seems better than similarly sized chinese ebay intercoolers. Its not just size with these... flow, fin design etc matters aswell.
Tbh if i did not care about the money at all, then EVO2 kit would have been a bit better... but it costs over a 1000 eur. and in longterm if i happened to upgrade turbos(for example when they finally fail) then i would have to take it off, sell it to someone at a huge discount and buy an even bigger one... evo3 or vrsf 7.5 inch etc...

So my plan was not to invest a lot into a bolton car intercooler that gets replaced with a bigger one at some point probably anyway. Thats why i was looking for a used one from someone who was at the point of upgrading turbos and switching intercoolers.

Of cource someone would think that "hei, then just buy the biggest intercooler right away." But that isnt good for a stage1 or stage2 car - it would introduce turbo lag and so on.. also big intercoolers weigh a lot.

It depends on nothing. The EVO 1 is just too small, and doesn't do anything beyond being over priced and performing worse than other options.

I've researched intercoolers extensively and here is what I found:

Bar and plate is absolutely superior to tube and fin
- They are more durable
- There are more options (easily scalable)
- While tube and fin SHOULD cost less, bar and plate options cost less
- Have more internal Surface area for better convection cooling

Things that aren't real:
-Tube and fins cooling down quicker - Though they do heat up quicker because they have less thermal mass
- Larger intercoolers causing turbo lag (within reason)


Things that are real:
- Tube and fin do weigh less than a comparable bar and plate cooler, but again this means they have less thermal capacity, hold less heat and heat up quicker.
- Tube and fin have less internal restriction, but it typically amounts to about literally a handful of whp, and about 1% or so WGDC - also, it means they don't cool as well.

[AmuroRay]

Originally Posted by B21

For a 400 BHP running 18 psi boost tune on stock turbos on a Northern European climate the Evo 1 is more than adequate..as was suggested it’s much more than just simple frontal area..

It literally is not.
For the record, my intercooler can get within 5F of ambient temps - within 12F of ambient on consistent back to back runs.

No Evo intercooler is doing that. It's about surface area, and anyone who says otherwise either doesn't know or they are marketing a crappy product.