Supercharged K20a2 Vtec - Race Spec by cptkirk

9 minute(s) of a 377 minute read

AUTOMATIC THROTTLE BLIPPER

I made a first pass at the design for the throttle blipper solenoid setup. I am still wanting to explore having the push/pull linkage above the solenoid but need to have a think about it. However before doing this I need to model the brake hose that heads over the solenoid to ensure no clashing, I've got feeling its going to....

The M8 fittings are overkill but are driven by the ID of the springs. The springs work in two ways, one they take the jolt out of the soleniod action and two they allow the throttle to be pushed past the resting position of the solenoid as when the throttle blips I don't think it will need to be wide open, time will tell and an amount of adjustment is being built into the system.

I made a video that I will post up on you tube of the model working, I will tag it into this post once its done uploading.

Here's a couple of renders of the first pass:

4-27-2015

Throttle blipper video

I have no other point of reference to compare it to but it seems OK, nothing has flaked off so I am guessing its OK. One thing I would say is that if you're looking to reduce engine bay temps I'd wrap it as well as you can see how hot it gets even with the ceramic coating:

4-30-2015

AIR FILTER HOUSING (AFH)

My obsession with feeding cold air to the supercharger has reached new heights. Those of you that have followed this from the beginning will know that I originally had a K&N Apollo, which when I first went to the dyno was told that it was robbing me of about 15-20bhp over an open throttle body (no filter - you can make gains with a well designed intake with filter) and when looking at it now the filter in it is tiny, I mean tiny....

This led me to buy a different filter when I went intercooled, it was much bigger and better but it just lived in the engine bay, near the nearside scoop so wasnt necessarily getting the cold air it should. I guess part of me was thinking "oh well, it's intercooled now so that'll be alright....Nope.....it was pointed out to me at the dyno that the cooler the air going in the cooler the air coming out the charger and therefore the less work the intercooler had to do and therefore a much more efficient setup could have been designed. Also the inlet was all 3" from filter to throttle body.

As with the new throttle body effort this was all brought about by my wanting to re-instate the 72mm throttle body that the car had been dyno'd on, as I know from many many posts on K20 supercharged forums, in the US, that superchargers need as little restriction as possible ahead of the throttle body to make good numbers and there have been gains of over 30hp just from swapping from a std TB (62mm) to a 74mm with 3" piping from filter. Couple that with nice dense cold air and you got a recipe for a good bang.

I decided that I needed to suck cold air from both scoops to a bespoke enclosed air filter housing, so that is exactly what I am going to do.....

it will be fed by two 3"/76mm pipes which have a combined cross sectional area greater than a single 4"/102mm, so no restriction there. The air filter is the one you have seen in previous photos of the throttle body setup, with a 4" outlet, actually its not a 4" outlet, its more like 95mm but never mind, its still bigger than the 3" it had before and the area of the filtering fibre is considerably greater than the old one, and p!sses all over the Apollo piece of crap.

My problem now is that with such a big air filter and housing it cant go where it used to and it is a very tight fit, that tight that with jsut the filter (no housing) i could only jsut get it on the throttle body. So I am utilizing a 4" Vee Band connection so that I can slot the AFH down into it mounted position, this has brought about its own challenges. I have had to make a new half of the vee band from acetal to be able to bolt the connecting half to the AFH, the other half remains aluminium. I have had to cut the neck off the filter to make if fit in the AFH also, that was fun.....not.....

As a nod to the viewing screen I put on the rear parcel shelf I am going to put a clear top to the AFH so you can see the filter as the top of the AFH will sit about 10mm under the perspex of the viewing screen.

I have made good progress with this but am not quite finished. Here are a few photos of the work undertaken so far:

Basic idea:

Where I started with the bare material:

Building it all up:

I will post more as it happens......

5-6-2015

AIR FILTER HOUSING (AFH)

More work went on over the Bank Holiday weekend, I got it all back together and looking smart.

In my quest to get the air filter to fit in there I also had to:

Reposition the Fuel Pressure regulator

Rework the throttle cable holder

Change the pipe routing for the intercooler

Change the orientation of the Intake Air Control Valve (on the bottom of the throttle body) by 180deg

Reposition the MAP sensor onto the new IACV block

Old versus new air filters:

Stevie G and his massive mill making the recess for the large end of the filter to sit in:

The odd shaped hole I needed to cut out of the air filter:

Holes tapped in the acetal before adding the vee band connection:

Vee Band Connection:

Filter in the housing:

Finally the Filter in place, note that the filter housing has its own 8mm exhaust bobbin support so the weight of it is not hanging off the end of the throttle body:

Here's the piping from the O/S:

you can just see the piping to the N/S: