Slightly OT head porting question

Curly · Postby **Curly** » Wed Jul 05, 2006 4:16 pm

Question for the collective wisdom. Our khanacross Hyundai Excel dropped a valve at last weekend's event.

We towed it home and pulled the head off to find one bent valve, and very little damage apart from that. Bores look fine, and there's only a slight bit of damage to the top of the #1 piston.

So we dropped the head off to a local specialist, who got enthusiastic when he found out the car was raced, and now wants to work his magic on it in return for putting some stickers on the car (and a couple of hundred bucks).

This is an X2 Hyundai - so it's the 8V mitsubishi based 1.5l efi engine.

He wants to shave the head a few thou, which should result in another half point of compression, clean up the valve seats and do a port and polish job.

Should I expect to feel a difference in performance, considering that the engine is otherwise completely standard? It only makes 62kw standard, but we've taken a huge amount of weight out of it, so every kw extra should be noticeable...

CT · Postby CT » Wed Jul 05, 2006 5:13 pm

Yep, more airflow is a good thing as is more comp. Might have to look into a bigger throttle body and extractors (cams too) if you wish to get the most out of it.

Curly · Postby **Curly** » Wed Jul 05, 2006 5:26 pm

CT wrote:Might have to look into a bigger throttle body and extractors (cams too) if you wish to get the most out of it.

Well yes, but it cost us $900, and we're winning events in it. It'd ruin the whole image if it looked like we'd actually spent any money on it.

Maybe if I could find a bigger throttle body that also looked rusty and corroded...

As to the cam (singular!), there is a little bit of pitting on the broken valve's lobe. Should I not worry about it, or should I try to polish it out a little?

CT · Postby CT » Wed Jul 05, 2006 5:54 pm

I see - I wouldn't worry about a little bit of pitting on a lobe then - run it till she cracks in half and then get another one! I'm guessing motors are in plentiful supply. I did read an article about a dual throttle body manifold on an excel - seemed to gain a few ponies. Fast fours maybe?

Curly · Postby **Curly** » Thu Jul 06, 2006 12:41 pm

Yes, I had a mate who did that conversion, however that was for the Alpha engined later model.

Was at the wreckers yesterday afternoon, picking up a radiator and a few little parts, when I noticed that the Astron engined Magna has the same bolt pattern for it's throttle body.

Will probably head back there on the weekend to pick one up and see if it'll fit. No idea how the standard computer will handle it, but as you said, if we blow up the motor, it's only about $300 for a new one.