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White 97 forged GtX28 ep91 build!


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Need some info I've tried looking it up .but can' seem to get a spot on answer.

I have 74.5mm wiseco pistons with scat rods and head work done including Billet camshafts 8.8-9.0mm lift and 272 degrees duration

im trying to do a compression test and my results are showing 8.1 which is about 125 psi across all cylinders

Abit puzzled where I'm going wrong 

 

any help would be highly appreciated 

Edited by Faiyaz.123
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8 minutes ago, Faiyaz.123 said:

Need some info I've tried looking it up .but can' seem to get a spot on answer.

I have 74.5mm wiseco pistons with scat rods and head work done including Billet camshafts 8.8-9.0mm lift and 272 degrees duration

im trying to do a compression test and my results are showing 8.1 which is about 125 psi across all cylinders

Abit puzzled where I'm going wrong 

 

any help would be highly appreciated 

What material had been took off the head then? 

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1 minute ago, maddox710 said:

What material had been took off the head then? 

Assuming you want this info

Full race spec head (extended port and polish, faced, valve seated and shimmed, including):

 Uprated Valve Seals

 Uprated Valve Springs (suitable for high lift billet cams)

 Uprated Valve retainers

 Solid buckets with lash caps, and shimmed

 Billet camshafts 8.8-9.0mm lift and 272 degrees duration

 

This was all done by zisco.

 

Also the compression test we done was with engine warm . What doesn' make sense to me is if they was something wrong then why get the exact same figure across all cylinders .We just doing some test before changing the tune.

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1 hour ago, maddox710 said:

Well if they'e taken meat out the combustion chamber on the heat then effectively they have decreased the compression ratio by  increased the space the cylinder has to squeeze the mixture 

Sorry bout that don't know what happen with that reply .

Ok so this means it' fine to have the trading I have now?

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On ‎11‎/‎11‎/‎2017‎ ‎09‎:‎24‎:‎00, Faiyaz.123 said:

Need some info I've tried looking it up .but can' seem to get a spot on answer.

I have 74.5mm wiseco pistons with scat rods and head work done including Billet camshafts 8.8-9.0mm lift and 272 degrees duration

im trying to do a compression test and my results are showing 8.1 which is about 125 psi across all cylinders

Abit puzzled where I'm going wrong 

 

any help would be highly appreciated 

As previously said. Work on combustion chambers will affect C:R as well as HG thickness etc. To reduce the C:R you could use a thinner HG, skim the block or head.

I have read somewhere before (maybe corky's engine tuning book) that if uprated/different spec cams have a lot of over lash this will affect static compression due to the scavenging affect of the cams.

I'm not saying this why but could be a possibility ?

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On 11/12/2017, 2:36:17, Flower said:

As previously said. Work on combustion chambers will affect C:R as well as HG thickness etc. To reduce the C:R you could use a thinner HG, skim the block or head.

I have read somewhere before (maybe corky's engine tuning book) that if uprated/different spec cams have a lot of over lash this will affect static compression due to the scavenging affect of the cams.

I'm not saying this why but could be a possibility ?

I agree to this it makes sense we have gone over it and have found no bad effect besides lag and cr but motor is still health and going higher.

Thank you for all the inputs .now back to stressing about gearbox 

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  • 2 years later...

So maybe it's time a update this .

After my fall down with my previous 4efte engine bending the crank (don't know how)

 

I've gone 5e will post some pics currently running .I've stopped at 1bar of boost and rev limit at 8krpm .gearbox doesn't seem like to like it but yeah we know there's no alternative to it hence why I lost interest in it.

I've gone side exit its fun even though the person stuck it out the bumper instead of it sitting flush .

 

Currently trying to figure out out why my p/s belt keeps splitting its a 4efte p/s am I using the wrong length or is there a spacer to be added. Help would be appreciated. I think this is my stopping point before I ended selling or stripping. 

 

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Edited by Faiyaz.123
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