[Mk2] [Turbo] Starting build

[bobhatton]

Did a trial fit of my crank before taking the block off to have a girdle made.





This was the block with the balance shafts still in place



This is the type of girdle that I will be using.

[Dangerous]

Nice... That girdle looks VERY familiar....which block are you using???

[bobhatton]

The girdle photo just came off the net and is fitted to a 3S block, the block I am using is a 1999 5S and Jun billet stroker crank and dry sump system.
Got to keep it all together at 900 hp and 9000 rpm

[Dangerous]

900hp!!! Please enlighten further of the spec!!! I take it your now drag racing aswell as sprinting??...
I'm pretty sure that picture is my block that rogue built with a girdle.. FYI you'll need longer arp's to hold it all togther...

[bobhatton]

No, only sprints. Its being built for that power so its nice and strong but most of the time will be around 600 HP on pump fuel, the 900 HP will be on race fuel.

Yes had contact with ARP to sort out the studs and what they will be made of.

Just building the bottom end first, then will move on to the head later.

[bobhatton]

Oil squirters now fitted in the block and the block girdle should be complete by the weekend. This is being made on a CNC mill so I will have the drawing if anyone needs one making later. Being made from EN8 steel.

Pistons on order at 7.5 to 1 compression ratio for the 2 bar boost that will be used
The rods will be a custom set made by Arrow Precision
I will get photos on next week

[greeny]

Oil squirters now fitted in the block and the block girdle should be complete by the weekend. This is being made on a CNC mill so I will have the drawing if anyone needs one making later. Being made from EN8 steel.

Pistons on order at 7.5 to 1 compression ratio for the 2 bar boost that will be used
The rods will be a custom set made by Arrow Precision
I will get photos on next week

Why so low compression bob?

[bobhatton]

Its the correct way to do it, boost goes up compression goes down just like Toyota did when going to the Rev 3 from the Rev 2.
I may need to run the car on pump fuel also, if it was just race fuel then it would be 10.0:1

[bobhatton]

When an engine is designed and tested one of the main things that will be found will be the ignition timing, this is a fixed figure and comes about from the head design.

This is something that should not be changed apart from a few degrees. When a turbo is fitted to an engine or the boost is turned up, the timing must still stay the same and it’s the compression ratio that has to change to suit the boost and fuel used.

If the above is not done and it’s the timing that gets retarded to stop detonation then that will give far less power and lots of other problems like engine over heating, cracked blocks, cracked exhaust manifolds and damaged turbo.

You just have to look at what Toyota did when changing from the Rev 2 to the Rev 3, the boost was increased, from what 0.7 bar to 0.9 bar, and did they just retard the ignition timing, no they spend lots of money making new pistons to drop the compression from 8.8:1 down to 8.5:1. Now would they have done that if you can just back the timing off?

[greeny]

I know the theory, but 600hp on pump can and has been done at 8.5-1 many times, should be even easier with the size of turbo you're going to be running to get to 900hp.

What ecu and knock detection are you going to be running?

[bobhatton]

Yes it can and has been done but not the right way in my mind.
Its a Motec ecu and will not need any knock detection. If I get any knock my design will be wrong.

I have a turbo to give 400hp, another to give 650hhp and will have to get another if and when I go to 900hp

[Century Motorsport]

Thats crank

The girdler is nice too - definitely something I would do if I did another big power build!

Looking forward to seeing the outcome of this beastie.

[stephano]

Does this mean im in danger of not winning this year?

[Kongaroo]

Looking good Bob! Where did you source the crank? Is it significantly lighter than the standard crank? I bet it cost a heck of a lot of money

[bobhatton]

Does this mean im in danger of not winning this year?

Yes as long as I stop helping you with your car and get on with my one, or I may have to unbolt all my parts and take them off your car

[bobhatton]

Looking good Bob! Where did you source the crank? Is it significantly lighter than the standard crank? I bet it cost a heck of a lot of money

I will have to check but it is not light as the counter weights are 180 deg. Light weight is not the best way to go, its all down to balance and that can only be done big counter weights.
I got it from the USA, $1200.00 + shipping +tax +vat

[Leakie Tbar]

What rod ratio are you going to be running?

[bobhatton]

Its a Jun crank with the same stroke as a 5S but with 3S big ends so will be stock 3S rod ratio. Even with that there is not room to give a piston dish to give 7.5:1, its going to be 8.0:1.
If it was not the 5S stroke I could have got down to 7.5:1

[Leakie Tbar]

i would love a stroker with a honda style rod ratio

[bobhatton]

If I could have got a longer rod in I would have, but there is just no room with a dished piston