I have a few S5 TII UIMs and LIMs kicking around doing nothing. I was wondering if there was anything I could to do a pair such as porting that would give my engine more power if I slapped it on. I've searched around but couldn't find much info.

Thanks.

 

port matching is probably going to be almost unnoticable for increasing power. increasing the whole port diameters inside the intake requires extrude honing which is pretty pricey, also has to be matched to the engine otherwise you may wind up losing power due to the runners now being too large and choking up due to the intake or exhaust ports inside the engine.

IMO it's relatively useless to modify the intake manifold aside from a few quick passes with a dremel to port match, which may net ~1% gains. it's not something i try to sell because the cost per HP is a bit steep.

 

Interested

I think port matching and extrude honing is about the best thing that can be done.
Depends on the build level, on a stock engine I wouldnt bother but on a modified motor it might gain you a few ponies.

As an NA driver we have limited options so this might be worth it, but again only on modified engines.

Just for the record, I was considering coating the intake & header on my NA with kind of heat isulation (ex. ceramic or zirconium)
It is a bit pricy but if you have headers and intake coated, the intake temps will drop a good amount which also has other advantages as freeing up a few ponies.
(Assuming the task has been done properly and carefully)
I am still mesuring temps on the stock parts to get an idea whats going on before doing any work.

I would be happy to hear from someone who actually tried port matching or extrude honing. NA or FI.

 

turn the multi chambered plenum into a single chamber plenum. watch the magic.

 

Thanks for the info people

So you think having my intake manifold coated with some sort of heat insulation would help with intake temps?

 

it will.

how much, and if you will gain any noticeable power though... that's the real question.

 

Results?

 

i'm considering some kind of insulation too. C ludwig posted a dyno of a car and they did normal runs, and then put a fan right on the intake, and it picked up a bunch of power, 10-12hp. so if you can keep the intake cooler it helps, the problem is how to do it without cutting a hole in the hood and mounting a fan on it....

part B, is i'd just look inside and take a dremel to any big casting flash/boogers/etc no need to go much further

 

could try ceramic coating the external case of the manifold. cost is about $100 though, for maybe a couple of hp.

 

you need accurate computational fluid dynamics modeling software and/or a lot of controlled dyno testing to determine this design's effects on the powerband.

 

i mean, why not try it? people do dumber **** to their fc's all the time.

 

Oh, quiet a few responses
I believe that coating the intake manifold with heat insulation (upper & lower) certainly does reduce the intake temp.

Ever stopped during a long highway/autobahn trip and opened the hood ?
No ? Its worth a try. The rotary produces heat like hell. You will be surprised.
On my NA for example the intake tubing/air filter housing is so hot you will burn your fingers when touching.
So clearly the airflow that goes through this tubing and down into the motor must be hot as hell too.

Following this idea, I think that it might be a good idea to reduce intake air temp by:

1. Coating the exhaust header / manifold with heat insulation to generally reduce engine bay temps.
2. Coating the UIM/LIM intake manifolds to specifically reduce intake air temp.
3. Replacing stock air box/filter piping to get fresh air from outside (ambient air intake) This piping may be coated with heat insulation too for maximum effect
4. Wrapping the upper & lower rad hoses with exhaust heat-wrap stuff (Those hoses are close to the intake piping and are damn hot too)
5. On turbo motors, coating the hot side and manifold with heat insulation. Downpipe too if you are lucky with it

Ok emissions may change a little bit with another intake air box/filter setup but still in spec & you wont fail the sniffer test. Its not that I am going to remove air pump and cat and try to pass the sniffer.
Comfort and drivability are unaffected by these modifications. I dont know how much temp drops with this done but I bet it might be a good chunk. It costs a bit but I have seen way bigger waste of money on the FC. No the term "waste of money" might not be apropriate. I should better call it "priorities".

I installed a temperature sensor on my stock S4 NA engine. (Got a high flow filter but I dont think that matters)
Point being, @ 17,3 C° outside temp I got 43,3 C° 25 cm before the throttle blades on my Intake after 30 km trip to work. Thats more than 2 times increase in temp and we just passed the air filter and are about to enter the UIM.
The results are similar for all the other trips. When comming to a stop temperature on the same sensor goes up to 70 C° sometimes after a few mins.

Feel free to give any feedback or correct me if I am wrong.