Heads.

[Rosssub]

I picked up a pair of Version 6 STI Heads today, thought I\'d take a few Pic\'s comparing them to my BH5 TT Heads.

 

Left is STI - Right is BHTT. Note the Double Stripes on the STI Cams:

 

Version 7 Cams have 3 Stripes, 2 at one end and 1 at the other.

 

These are STI Shim Under Bucket Valve Lifters:

 

These are BH TT Shim Over Bucket Valve Lifters, (more likely to fall out at high RPM).

 

Left is Version 6 STI - Right is BH TT. (gaskets are identical)

 

Top is Version 6 STI - Bottom is BH5 TT

 

 

Lift/Cam Lobe Height:

BH5 TT In - 46.5mm

BH5 TT Ex - 46.7mm

V6 STI In - 45.3mm

V6 STI Ex - 45.7mm

V7 STI In - 45.3mm

V7 STI Ex - 45.7mm

 

I can't measure the Duration properly, but can easily see that the STI Cam Lobes are much rounder. Giving much longer Duration over the TT Cams.

 

All Cam Shaft Journal Sizes match perfectly, TT/V5/V6/V7.

 

Version 6 STI Shim Under Bucket Valve Lifters:

 

Lifter/Bucket removed, leaving Shim on Valve:

 

Shim removed:

 

BH5B TT Shim Under Bucket Valve Lifters:

 

Shim removed:

 

Bucket removed:

 

Left is V6 STI - Right is BH5B TT:

 

 

Showing Duration difference:

[Rosssub]

I\'m thinking I might fit the Version 6 STI Cams, Valve Springs and Buckets into my original TT Heads? ???

Here\'s a Mint Write Up on Porting heads, full of Version 7/8/9 Head Pics. Including some EJ255 Heads:

http://mnsubaru.com/threads/head-ports-comparison.4212/

[rex-leggy]

why dont you just use the sti heads?

[Rosssub]

 rex-leggy said:

why dont you just use the sti heads?

Just looking at the difference in Inlet Port Size/Shape/Flow Capability.

I was planning on Port Matching with the Manifold, then Polishing both. The TT Heads need a "Lot" less cut out?

Or is the Tighter Port on the STI Head, also the Tighter Circumference around the Injector Opening. For Higher RPM Flow/Higher Boost Flow/RPM Fuel Atomisation etc?

[rex-leggy]

just port match the sti ones . look at pic 5 the sti cases will flow better WAY less material further down.

[Guest]

Divider looks better on the STi heads doesnt it? Russ is using TT heads isnt he? Hopefully have some results this year...

[rex-leggy]

I have some pics somewhere of the porting I got done and he took ALOT out haha.

random how the tt one are opened up by the gasket. maby done previously

[Rosssub]

I\'ve got a Rev A TT Head here with Identical Ports, I don\'t think they\'ve been touched.

Lowering a $2 Coin into the Ports on both.

The STI Ports are clearly about a 3-4mm bigger I/D. Just much tighter at the Gasket.

[soopersubaru]

TT heads flow better than STI ..in standard un modified port configuration....Who would have thought? lol.

Easy as to do the shim under mod and swap the sti or some decent cams into as well.

[Guest]

 soopersubaru said:

TT heads flow better than STI ..in standard un modified port configuration....Who would have thought? lol.

Easy as to do the shim under mod and swap the sti or some decent cams into as well.

Flow bench tested with evidence or hearsay?

[rex-leggy]

just after some more attention would be my guess.

without evidence ill trust my eyes

only place flow would be effected is were the manifold meets the head. because of the extra material at top.

which I recken would make bugger all difference on a bench.

[soopersubaru]

 evowrx']

[quote name='soopersubaru said:

TT heads flow better than STI ..in standard un modified port configuration....Who would have thought? lol.

Easy as to do the shim under mod and swap the sti or some decent cams into as well.

/quote]

Flow bench tested with evidence or hearsay?

have a careful read here. "fuji" knows all there is to know about flow. http://forums.nasioc.com/forums/showthread.php?t=903873&highlight=head+flow

Also here. http://forums.nasioc.com/forums/showthread.php?t=1728481&highlight=head+flow

[Rosssub]

Pictures of Lifters/Buckets, Shims and Cam Lobes added. ;D

I\'m using the Version 6 STI Heads, but porting around the Gasket edges. Then Port Matching the Manifold.

These Cosworth Ports look good:

[Koom]

Have you got any comparisons of the exhaust ports? Cause that\'s where the power is hiding on these heads.

Have you checked the inlet gaskets against the ends of the manifold to make sure that the other side will end up the same as the heads?

[Rosssub]

 Koom']

Have you got any comparisons of the exhaust ports? Cause that\'s where the power is hiding on these heads.

Measuring up, Exhaust Ports between Heads are identical.

[quote name='Koom said:

Have you checked the inlet gaskets against the ends of the manifold to make sure that the other side will end up the same as the heads?

Yes, that\'s Port Matching. Runners match these Gaskets perfectly.

[rex-leggy]

comparison betweet v3/4 and ported

some others because everyone likes engine pics

[Rosssub]

Very nice. ;D

Is that with a Diamond Bit, then Sand Wheel?

[kamineko]

 rex-leggy said:

in the \'sweet jesus\' thread it looked like they plated or otherwise mirror polished the area around the valves on the combustion side. what is all that about?

also Rosssub, any further details on the V6 and BH5? what years and what model/revision was the legacy? thanks. i\'m making a list of the cam markings.

[Rosssub]

 kamineko']

[quote name='rex-leggy said:

img]https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-frc1/t1.0-9/317133_2496571978881_484188041_n.jpg[/img]

in the \'sweet jesus\' thread it looked like they plated or otherwise mirror polished the area around the valves on the combustion side. what is all that about?

also Rosssub, any further details on the V6 and BH5? what years and what model/revision was the legacy? thanks. i\'m making a list of the cam markings.

Unsure on the dates for the Version 6 STI Heads, STiNGR may know? The BH5 are the originals from my 2000 BH5 Rev B GTB.

[Koom]

 kamineko']

[quote name='rex-leggy said:

img]https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-frc1/t1.0-9/317133_2496571978881_484188041_n.jpg[/img]

in the \'sweet jesus\' thread it looked like they plated or otherwise mirror polished the area around the valves on the combustion side. what is all that about?

Prevention of carbon buildup? So no hot spots in the future.

Was that build done on an open deck block? Seems weird that they threw the whole HKS and Jun catalogue at it and didn\'t even pin the bores?

[boon]

It\'s actually a sleeved block, they didn\'t seem too worried about things moving.

[rex-leggy]

 Rosssub said:

Very nice. ;D

Is that with a Diamond Bit, then Sand Wheel?

I couldnt tell ya got some guy that previously worked at kelford cams to do them. he said he didnt make much $$ on the job, quoted me $600 or around that amount to do them and spent 3 straight days on them

yea nick after reading that thread he said there was no plating and that it was just polished.

seams like a waste to me .... cleaning brought mine up pretty good as ya can see and if you ran e85 it would burn clean anyway.

I remember reading somthing about surfaces being ultra smooth can be a bad thing also .... bugged if I know

[Koom]

It\'s the inlet ports that shouldn\'t be ultra smooth as it actually decreases the flowrate. It\'s all to do with the boundary layers created as the air flows through.

But smooth surfaces on the hot side is to prevent carbon buildup which is worse for flow etc

[Guest]

Whats the exhaust port size Ross 38mm? Isnt it awesome how you have all this stuff lying out to measure for me...

[Rosssub]

 evowrx said:

Whats the exhaust port size Ross 38mm? Isnt it awesome how you have all this stuff lying out to measure for me...

Yip 38mm exactly. ;D