Say AHHHHHHHHHHH! Opening the holes wide!


Tiny aluminum chips are falling like rain in my shop!

I've just finished removing material porting my intake elbow (goes between the TB and supercharger, which is also getting ported)

I have removed lots of material and really opened up the air pathways. I made sure to always be working on the bottleneck spots which were mostly the shelfs on the top and bottom about 1-3 inches before the supercharger. I removed about 3+mm of material there. The widest areas were not restricting so I left them well alone. The intake side 83 mm and exit are now about equal surface area.

 

Interesting. I too thought that the intake elbow is a huge restriction but I was worried that any kind of porting might mess with the sensor that plugs into the the back. I wonder if extrude honing would help as well.

 

I did this before with my 1st XJR and had no issues.

I did not touch any of the area near the sensor as that is not the restriction point.

Many test have shown that slightly rough/turbulent flows more than mirror smooth.

 

Gah, now it looks like I will have to take mine off and do it! What did you use? Angle grinder with carbide bit?

 

I highly recommend it, you will feel a difference. When my blower comes back I'll finish my port match to those dimensions.


Flex shaft with small carbide cylinder, stone wheel, 3m abrasive discs (love these)

This is just what I had handy at the time.


I used these for making these squid pens (see photo) which I am just about to sell out of the limited edition of 88. Since ink pen writing started with squid ink, my first pen was a squid. I thought it made sense, squid make ink, etc. Collectors went nuts for these!

If you feel braver than I do you can also port the intake manifolds, but since I killed my last car after messing around with the injectors, somewhere in taking them out, sending them to be cleaned and re installing them, one got cracked started leaking, so I'm staying the h-e-double toothpicks away from touching the injectors. "A man's got to know his limitations" applies here to me. This just re-enforces the fact that I don't really know what I'm doing, but I'm having lots of fun at it!

It has been almost a year since I bought my first xjr, I was looking back at my posts of "how do i remove a valve cover" and now I am changing tensioners, porting elbows, superchargers, etc, and have designed better intake tubes, wired up my 92mm MAF, installed meth injection, intercooler sprays, pulleys, wired uprated intercooler pumps and changed the direction of flow for the better, and I'm working on a few still secret projects too. It has been a steep learning curve, and hey, I've only completely destroyed one motor!

 

i like that approach, Fu#k the torpedos,full speed ahead.

 

Great WD, and I love the have a go approach.

PS. The pen looks superb, should be a hit, and you can have a tasty lunch as you go along.

 

HEY? has anyone ever heard of EXTRUDE HONING, it opens things up and takes out a lot of the humps and bumps along the passage way.

and you can have it smooth or slightly rough surface.

had it done to my inlet and plenum manifolds. V12 5.3L

 

Yes it works quite well, but it is not selective. In this case it would wreak havoc on the other holes in this elbow. It is perfect for intake manifolds and the like.

In this case it is more important to know where NOT to remove material.

 

some of what you say may be true, BUT you cannot really know where to remove(or add) metal with out a FLOW BENCH and its associated parts!

like TIG welding for aluminum for filling in metal, and i know you are only doing hit&miss methods.

but if it makes you feel happy,go for it!!

and without dyno you cannot know what works and what dont.

 

Yes and no,

In this specific case, making the more restrictive parts of this air flow route a little larger at the most restrictive spots and removing big bumps that protrude out into the airstream will absolutely yield improvements. By removing the shelf (the huge undercut) as the air enters the elbow, I have removed the source of eddys and turbulent back currents, and the same by removing the 4 bosses that were sticking out 1/2 inch each.

Remember the air is being sucked in through here, not blown in, so it will naturally take the route of least resistance. This is a critical distinction; blown vs. sucked

If I can remove turbulence and open the most restricting places a bit, it is 100% certain the flow will improve.

But I would not dare port my heads this way, as that is a very different flow dynamic. RonBros, You are dead on that if i tried this with my heads, I would could very well make them flow less, I'd leave that to the people who know what they are doing.

 

Here is a simplistic diagram showing what I did, where I removed material.

I left the shape basically the same, but:
removed the lip at the top by opening up the hole from 75mm to 83mm, this should significantly reduce turbulence
removed 6 protruding bumps (bosses) from the air path which also should reduce turbulence and increases the size of the hole for less air resistance
opened up the smallest dimension by removing material on the top and bottom shelfs as it necks down to the smallest dimension. Again, pretty straightforward that opening up the dimension here should reduce vacuum.


The in and out surface areas are about equal at approx 54 cm2

 

I thought in a perfect situation you should have not vacuum in the intake under full throttle. I may have misunderstood the way it was explained to me.

 

True, in a perfect situation there would be no vacuum...but I have reduced no less than 2 full pounds of vacuum from my intake as evidenced by my boost gauge reading 2 psi higher at the same blower rpm with just enlarging my intake track.

and in a perfect situation you would have positive pressure in the intake, your bank account would increase every time you look at it, and bras would not need to come in different sizes

I just spoke to a board member who is using my idea of the 90 degree silicon bend into the TB, who, while on the dyno, witnessed the silicon elbow being sucked closed, and when that was fixed, got +30 more HP, so it must have been under some serious vacuum. He is running a 2.6 liter TS which does flow quite a bit more than the 1.8 l Eaton. Their solution was to add a metal ring inside the 90 degree silicon elbow to help it keep it's shape and stay open. That must have been some serious vacuum to do that...

I think it is safe to say there is still room for improvement on the intake side, and opening bottlenecks, even if just a little here and there, ought to yield even small improvements.


p.s. just out of curiosity, have you ever measured your intake pressure at WOT?