Shane's URD MRKlll++ supercharger Build

[kwigs160966]

Didn't you go with 9.1:1? How long until your build is finished and will you still run pump gas?

 

[Gadget]

Compression ratio is something you need to discuss with your engine builder. Stock 10:1 seems to work very well with the URD system. If you reduce CR you will loose power when you are not in boost and can make the engine feel sluggish when you are not hammering down on it. In the end this is something you are your engine builder will have to decide together.

G

 

[kwigs160966]

Compression ratio is something you need to discuss with your engine builder. Stock 10:1 seems to work very well with the URD system. If you reduce CR you will loose power when you are not in boost and can make the engine feel sluggish when you are not hammering down on it. In the end this is something you are your engine builder will have to decide together.

G

Thanks G I will call someone up and discuss my options!

 

[Torspd]

Didn't you go with 9.1:1? How long until your build is finished and will you still run pump gas?

What Gadget said.

Mine is now in its 3rd iteration, 9:1. I am not sure how long until it is finished. I will be running pump gas. Depending on certain power levels, datalogs, and if I choose to do meth or E85, will depend on what the other data says is required.

With 9.2:1 most previously, it didn't feel noticeably slower out of boost. Mainly because the turbo fed the engine well, even when not in boost.

 

[shane881510]

Thats something I'll take in. sounds as if I'll go back with 10:1 cr. makes this build alot Easyer anyways. thanks guys. I can start to order parts now

 

[shane881510]

What's the benefit of a forged piston over stock if the compression ratios are the same.

 

[Gadget]

Durability.

The stock pistons are made in a way to keep production costs very low. The material uses a high silicone content to keep the expansion rate very low. This helps with cold start emissions by allowing the piston to cylinder wall clearance very tight. The down side is they can be very brittle and when you add boost and get some knock they can crumble like a dirt clod. The common failure point is the ring land that supports the compression ring.

A forged piston uses a different process and stronger material. Production cost is much higher and are not commonly found in production engines except high end stuff and aircraft. Durability is much higher and tend to stand up to boost and knock much better.

Down sides are cost, heavier weight, high expansion rate so they tend to be loose when cold and are prone to piston slap until fully warmed up.

G

 

[GrumpyOldMan]

Durability.

The stock pistons are made in a way to keep production costs very low. The material uses a high silicone content to keep the expansion rate very low. This helps with cold start emissions by allowing the piston to cylinder wall clearance very tight. The down side is they can be very brittle and when you add boost and get some knock they can crumble like a dirt clod. The common failure point is the ring land that supports the compression ring.

A forged piston uses a different process and stronger material. Production cost is much higher and are not commonly found in production engines except high end stuff and aircraft. Durability is much higher and tend to stand up to boost and knock much better.

Down sides are cost, heavier weight, high expansion rate so they tend to be loose when cold and are prone to piston slap until fully warmed up.

G

Thanks for the explanation

I knew that forged were stronger due to grain alignment, but wasn't aware of expansion rates being different...would that mean you need to warm up an engine with forged internals a little more before beating in it due to larger clearances??

Dave

 

[Whitebeauty]

Thanks for the explanation

I knew that forged were stronger due to grain alignment, but wasn't aware of expansion rates being different...would that mean you need to warm up an engine with forged internals a little more before beating in it due to larger clearances??

Dave

R u home yet I dont cvthe ticking time clock on the bottom.

 

[GrumpyOldMan]

R u home yet I dont cvthe ticking time clock on the bottom.

I won't make it to Land O Lakes till the evening of the 23rd....then it's back to work on the 24th - no rest for the weary!

 

[shane881510]

Project take engine out and rebuild It is about to start.

 

[Torspd]

When the engine is back in, time to see what that MKIII can really do!!!!

 

[kwigs160966]

Project take engine out and rebuild It is about to start.

Yeah me too man. I have most of it apart just the bell housing and motor mounts and starter and exhaust lol ok may e I have more to go than I thought. I decided against a stroker kit but am going to sleev it with new rods pistons and possible upgrade the heads. How about you

 

[shane881510]

Motor mounts is all I have left and I'm pulling it out. Rods and pistons is all Im gonna do. And new tranny, busted the output shaft sleeve on mine

Input shaft not output. Where the throw out bearing slides on

 

[shane881510]

:frown: what a day

 

[Gadget]

Looks like you ran out of ceiling to get that engine up high enough.

G

 

[shane881510]

Almost..had a half inch of clearance. Just enought to pull out over front.

 

[shane881510]

#4 cyclinder

 

[shane881510]

Broke ring carriers. #4 piston

 

[Torspd]

Look at that poor ringland. It's gone to a better place.

How long until new components arrive?