rough bhp

12th June 2012, 15:52

On a 750 motor club stock hatch. skimming 2mm of the head and cleaning every thing to like new. then using the late domed pistons and a 0.6 mm head gasket. i have a sand blasted exhaust manifold to clean and new down pipe with a straight threw exhaust.
running on a omex ecu what bhp should i be seeing roughly as i dont have a clue and people have all different numbers.

manic

12th June 2012, 16:06

2mm is a lot to skim of a head...
What engine are you using? 1.4 16v or the 1.6 8v?
As far as i can remember, you're not allowed to modify an engine, thus the name 'stock hatch'
Domed pistons, 2mm skimmed head and a thinner head gasket are classed as modified, as far as im aware?

13th June 2012, 04:36

Its a 1.6 8v vtr 2003 block and sump. and a 98 early head
Skimming head down to 110.5 mm annd the domed pistons are from a 2003 vtr. and gaskets are free.
i know its all ment to be standard are they are just from different models. been told the best head is a s1 pug rallye. again its a standard item. so the rules are in place and worked to but its how you read the rules tho.
others have gone further too with the mixing and matching

manic

13th June 2012, 04:45

about 400bhp

13th June 2012, 05:06

my telepathic dyno says 245.6bhp and 11lb/ft

13th June 2012, 08:56

You're not really going to gain anything really mate. If anything, you'll gain a disqualification. The way I see it, is if you're using bits from DIFFERENT engines, it won't be stock, therefore, it isn't a STOCK car.
Also, may I ask why you want to skim 2mm off the head (raise compression I'm guessing) and put domed pistons in (lower compression)... Makes it seem a little worthless doing it to me?

13th June 2012, 09:29

You can use any standard parts from the manufacurs range. ie late pistons and early head. can blue print engine. line bore main ends etc any thing to up compession and to make it as smooth as possable

manic

13th June 2012, 09:59

I dont think you'll be able to use the rallye head and its cam, as its 270 degree of lift. They'll spot that

13th June 2012, 10:00

Quote:

Originally Posted by jasonmayall

You're not really going to gain anything really mate. If anything, you'll gain a disqualification. The way I see it, is if you're using bits from DIFFERENT engines, it won't be stock, therefore, it isn't a STOCK car.
Also, may I ask why you want to skim 2mm off the head (raise compression I'm guessing) and put domed pistons in (lower compression)... Makes it seem a little worthless doing it to me?

Domed pistons will increase compression, due to taking up more space in the combustion chamber. Dished pistons will lower compression

13th June 2012, 10:14

Rallye head is ok but have to use a kent kc750 cam to suit. ie big or small jurnal non roller head or the roller head.
another question . why do most drivers use the non roller head even tho all the cams have the same loabs. so i thought that the rollers would be better as less friction

manic

13th June 2012, 10:19

I think the rallye head has an odd journal size compared to normal blacktop and the roller rocker head. I assume people use the non roller rocker heads as they have tougher valve springs as standard, especially in the case of the rallye head with its green springs

13th June 2012, 10:56

Quote:

Originally Posted by jasonmayall

You're not really going to gain anything really mate. If anything, you'll gain a disqualification. The way I see it, is if you're using bits from DIFFERENT engines, it won't be stock, therefore, it isn't a STOCK car.
Also, may I ask why you want to skim 2mm off the head (raise compression I'm guessing) and put domed pistons in (lower compression)... Makes it seem a little worthless doing it to me?

I suggest you look into the rules for racing in certain classes. You are talking twaddle.

13th June 2012, 11:39

Roller rockers are not reliable at high rpm's, they are also said to be a lot "heavier" which I assuming alludes to rotational mass

The none rollers have solid lifters