J__

ok so I did a bit of research and here's what I have. The specs for the filter provided my BMS is 76mm opening with 125mm top and bottom base, 165mm length. According to K&N filter size chart, this would work perfectly:

Filter model RU-5111
http://www.knfilters.com/search/prod...x?prod=RU-5111

of course it won't look as nice and flush as the one BMS provides but it won't rub and become useless. I haven't tried it yet but technically speaking it should be the perfect size.

Knightmare69

I'll see if my shop carries it and if it will work with the custom intake I'm working on.

Kevin82

That's a good amount of dirt in the tubing. Imagine all of the dirt that didn't stick to it and went straight inside your engine. Is that white stuff grit?

J__

not sure what that is. Felt smooth, but seems to be stuck on the tube, didn't come off when I rubbed it.

****ty thing is I have to drive with this for another month (unless I put on the stock airbox) China doesn't seem to carry the full K&N lineup and don't have the ru5111 filter. Ordered from amazon and getting my friend to pick it up when he goes back to the states end of next month.

Kevin82

Put your stock air box back in ASAP!

From the looks of your picture, the holes are too big to keep the filter on. Absolutely do not use the k&n until replaced. You don't want big pieces of dirt/sand floating in your engine oil and clogging up your oil filter. Your oil will turn to sludge with all that extra dirt.

Knightmare69

Add on the quality of the air in China + condition of roads there that throw up substantial debris I also would recommend that you change back to your stock air box. Also, how were you not able to find a replacement filter? There are tons on Taobao and Tmall all the time.

J__

I left my stock filter in my parent's house. I don't have the key and they are out of the country...

Taobao/tmall doesn't have that exact size.

I super glued the holes together and going to flush the engine oil as soon as I get the new filter. So hopefully it'll hold up for a bit

kevink2

From Burger, Published on Apr 26, 2012 :

"This plug and play air intake system unlocks 7-10hp to the wheels from your gasoline C250 engine. In addition to the extra power throttle response is improved and sound is dramatically improved ..."

Burger also said the JB added 30 hp to the engine, but it was not peak hp, rather the hp related to the big low end torque boost. So I question the advertised gain. Also, they likely dyno'd it with hood open so the intake had plenty of fresh air to take in.



If you are working on an intake, be sure to do oem/burger/Knight measurments of air temps in manifold and in the filter. Also, most important is pressure drops at WOT and 5500 rpm. I use the dwyer 0-100 in-h20 differential pressure measurment gauge.

www.dwyer-inst.com/Product/Pressure/DifferentialPressure/Gages/Series2000/ModelChart

You have 2 small hoses to check pressure drop across and 2 points in the system. On my tracked 3rd Gen Rx7, I found that a drop-in OEM filter pad and no filter installed, had the same drop from pre filter tube to exit filter-box tube. The resisance was at the joint at the filterbox entry.

.

Knightmare69

I don't have access to tools to do measurements such as those you listed. Truthfully I knew that the intake wouldn't "unlock" much aside from in increase in noise. The OEM system is designed quite well short of the long intake tract. I'm planning on a hybrid BMS/OEM intake system but my resources are limited here in Hong Kong concerning the places that stock K&N filters. I'll see what happens and get back to everyone when I have something complete.

Knightmare69

I went to my shop today and swapped out to a different sized filter, happy to report spacialy it is a huge improvement. Ample space between the filter and engine cover and ample space between the filter and the problem area of the stock box that rubs against the bms provided filter. This is the filter or similarly size filter that bms should've provided from the start.

The plan was to modify the top half of the stock box to cover over the new filter but my shop said they will try to make something first before resorting to hacking the stock box. I have the part number somewhere, I can't find my receipt ATM.

DecemberHeat

nice! are you selling this? Is this the same size as RU-5111?

kevink2

The Dwyer gauge is about $60 US. Pressure drop across the filter asembly is everything in determining if you have helped or hurt the power, other than expensive dyno runs.

.

kevink2

You have an excellent "Juice Box" for kicking up the low to mid range torque. Unfortunately, your claim of 20 hp gained, was misleading as it was not peak hp, but rather hp related to the midrange torque boost, which is not standard practice for reporting hp increase.

It would be excellent if you were to post your before and aft dyno runs, as you did before.

.

Knightmare69

I'll have to look into the Dwyer Gauge but I've already scheduled 3 dyno runs at the cost of about $190 USD. As for the BMS tuning box, well I went with another brand that to me seems more complete. I'll find out the results on the dyno this weekend. I'll post results and video then in a separate thread.

DecemberHeat- No I'm not selling this but yes, this is part number RU-5111 so you can do this yourself if you already have the BMS adapter.

DecemberHeat

Great! Please let me know the progress of the air box too. Would prefer the cone filter shield away from engine bay (hot air!). Cheers.

Knightmare69

That's gonna be a while I think. The shape of the box and misc parts protruding from the box make it difficult to create a shield easily. Not to mention one that actually seals. When I have time, I'm going to cut out some shapes and see what I can come up with.

However, for our turbo models, power is more reliant on the air being charged by the cooler itself more than the intake air. A better mod would be a bigger intercooler or maybe even just heat shielded hoses from the intercooler to the turbo. Whatever the case, I'm doing the heatshield for the intake simply for myself in a OCD manner, I'm pretty sure the difference is negligible.

DecemberHeat

I do understand that. Just liking the sound that comes from the intake. :-)

Intercooler + Tunebox from Brabus (B20/25 S) or Carlsson (C-Tronic 20/25 S) are costing AUD4,000. That's ridiculous for the % of hp / nm gain.

kevink2

The reason I gave the Burger Box praise for the C250 was for the average joe who could spend less than $300 for a plug and play that you could really feel. I know there is another option out there (Kleeman?) that is more than just a low/midrange boost increase. It adds about 20+ hp at the top end, and alters parameters for better throttle response from a stop, and a dyno run the has a steeper torque rise from the start, and of course it costs about twice as much.

.

Knightmare69

Actually i'm using a brand called TMC tuning out of Ireland. Manufactured in Germany. Runs digital microprocessors and connects multiple points on the car. I'll be doing my dyno hopefully this weekend at which point i will post pics and vids in a seperate thread.

kevink2

^ Great !

The Kleeman Numbers for a C250

250-K1: K-Box. Up to 245 HP and 372 Nm (276 lb-ft) of torque.

250-K2: K1 + a stainless steel exhaust downpipe with sport cat and a hiflow air filter.
Up to 255 HP and 385 Nm (285 lb-ft) of torque.

If these are legit est'd numbers at the flywheel, and hp is peak value, the gains could be +34 hp and +56 ft-lbs.

OEM = 221 hp, 229 ft-lbs

.

Knightmare69

On this subject actually I wanted to ask, our ecu's are adapative to a certain extent correct? How long would it take the ecu to learn/unlearn a tuning box? I still have my tuning box connected but I was thinking yo remove it the night before the tune and drive there stock so as to give the ecu time to readdress itself so I got accurate baseline numbers. Then of course install the box and get the new numbers. But not sure if there's enough time in between to give the ecu time to adjust.

Kevin82

So how is the new filter so far? Any more rub?

Knightmare69

None at all, I check it randomly to be sure but you can also see from the 3rd pic that there is ample room between the filter and bottom of the airbox.

DecemberHeat

I can confirm that too. Had changed to RU-5111 for about a month. All good and nothing rub. Good size but would prefer a bit bigger. :-)

Knightmare69

I'm not sure if bigger would really bring much benefit. I have however considered a longer cone filter, one which would fill in the space of the box more but since the current one works I have no need to mess with it.