[Rowbo]

Hey.

I am starting a fresh engine rebuild as my 7afe has now done 304,000km. Still going strong but I can feel it starting to lag.

I am starting this build as this car has been in my family since we bought the car brand new in 1997. I am beefing up the bottom-end with forged internals (due to track days). It will also remain N/A. Was just wondering whether the Silvertop will be better for N/A purposes as alot of people stick to blacktop for forced induction?

Parts I have already:

ARP 4age main and head studs.
ACL Race Series bearings.
ACL thrusts
ARP 3/8 rod bolts
Belfab Racing forged 7afe rods.
16v timing belt and Renault Espace 116 teeth timing belt just incase the 16v doesn't fit after using the 20v oil pump.
CamTech N/A cams with full head rebuild bits.
Walbro fuel pump
3sgte fuel injectors
oil catch can.
Haltech ECU
Not buying pistons till I know which head to use.
Not buying gasket till I know what compression I am in for.

Anything else I have missed.

[5TALTH]

Hey there

Silvertop is better for N/A as it has a smaller combustion chamber so therefore higher compression you would then get it ported, Blacktop has a larger combustion chamber (not by much though) but also has larger intake and exhaust ports so its kinda a catch 22, i would reccomend a silvertop if your going to be picky though.

Cheers
Danny

Rowbo, on 02 June 2011 - 11:06 AM, said:

Hey.

I am starting a fresh engine rebuild as my 7afe has now done 304,000km. Still going strong but I can feel it starting to lag.

I am starting this build as this car has been in my family since we bought the car brand new in 1997. I am beefing up the bottom-end with forged internals (due to track days). It will also remain N/A. Was just wondering whether the Silvertop will be better for N/A purposes as alot of people stick to blacktop for forced induction?

Parts I have already:

ARP 4age main and head studs.
ACL Race Series bearings.
ACL thrusts
ARP 3/8 rod bolts
Belfab Racing forged 7afe rods.
16v timing belt and Renault Espace 116 teeth timing belt just incase the 16v doesn't fit after using the 20v oil pump.
CamTech N/A cams with full head rebuild bits.
Walbro fuel pump
3sgte fuel injectors
oil catch can.
Haltech ECU
Not buying pistons till I know which head to use.
Not buying gasket till I know what compression I am in for.

Anything else I have missed.

[ap7]

I would definitely go with a black top...it flows alot better than a silver top, thus why it is more expensive than a silvertop head and harder to get.

Re the above reply....hmmmmm....i'll leave it to someone else...

[Rowbo]

I have opted for a silvertop with silvertop head-gasket and silvertop forged pistons with a shimed block so the pistons sit flush.

My estimates on the compression ratio:

Silvertop pistons + silvertop head gasket + shimmed block + silvertop head = 11.5:1.

Silvertop pistons + 7afe head gasket (0.4mm) + shimmed block + silvertop head = detonation.
I am going to opt for the top formulae of everything silvertop for a base estimation of 11.5:1 compression ratio.

Start building it sometime soon. See you guys in Members Rides.

Row

[bazda]

If you want to make the power then Blacktop no question about it.

Blacktop heads out flow a silvertop BY FAR. I have the flow rates for all the 4age heads.
The port design of a blacktop is superior over a ST.
To work a silvertop head to get flow rates like a BT would cost you an arm and a leg. And still wont be as good.

We have BTs running with 130kw atw using Toda cams in NZ and thats no porting to the head.

When you talk about compression ratio, you should not work it out based on head chamber size :S, its a combination of piston design, head chamber and head gasket.

[Shadow20v]

I've done this conversion 4 years ago and trust me my car is a Monster of note.
When I first started this conversion it was more for just having something a litlle faster than a normal twincam 20v, but I did not expect what was to come.
My initial build was as follows :
1) 7A bottom end, 7A conrods, Blacktop pistons, BT 20V head (gas flowed, ported and polished), 100mm ram tubes and our local MasterCams (290 duration cams at 8.5mm lift)
with this setup above the car made 175whp (129wkw).

I wanted more power and this time round I brought down a set of OBX adjustable cam gears and also opted for a twincam 16V 4-1 45mm branch.
With this setup the car made 134wkw and 198nm torque. (P.S this power is made only up to 7000rpm)

She does make more power higher up but just to be safe I've only tuned it up 7200rpm, until I get stronger rods with ARP studs.

Im still greedy for more power and I believe with the TODA or Kelford cams which has more lift I should creep over 140wkw.

This post has been edited by Shadow20v: 18 October 2011 - 09:24 PM

[bazda]

Shadow20v, on 18 October 2011 - 09:18 PM, said:

I've done this conversion 4 years ago and trust me my car is a Monster of note.
When I first started this conversion it was more for just having something a litlle faster than a normal twincam 20v, but I did not expect what was to come.
My initial build was as follows :
1) 7A bottom end, 7A conrods, Blacktop pistons, BT 20V head (gas flowed, ported and polished), 100mm ram tubes and our local MasterCams (290 duration cams at 8.5mm lift)
with this setup above the car made 175whp (129wkw).

I wanted more power and this time round I brought down a set of OBX adjustable cam gears and also opted for a twincam 16V 4-1 45mm branch.
With this setup the car made 134wkw and 198nm torque. (P.S this power is made only up to 7000rpm)

She does make more power higher up but just to be safe I've only tuned it up 7200rpm, until I get stronger rods with ARP studs.

Im still greedy for more power and I believe with the TODA or Kelford cams which has more lift I should creep over 140wkw.

If you need Kelford cams, I supply them at very good prices!

[Shadow20v]

bazda, on 25 October 2011 - 07:26 AM, said:

If you need Kelford cams, I supply them at very good prices!

Cool! Quote me price on the cams inclusive of shipping to South Africa.

[bazda]

Shadow20v, on 26 October 2011 - 11:33 PM, said:

Cool! Quote me price on the cams inclusive of shipping to South Africa.

4age 20v cams are $950NZD

[7afe]

Shadow20v, on 18 October 2011 - 09:18 PM, said:

I've done this conversion 4 years ago and trust me my car is a Monster of note.
When I first started this conversion it was more for just having something a litlle faster than a normal twincam 20v, but I did not expect what was to come.
My initial build was as follows :
1) 7A bottom end, 7A conrods, Blacktop pistons, BT 20V head (gas flowed, ported and polished), 100mm ram tubes and our local MasterCams (290 duration cams at 8.5mm lift)
with this setup above the car made 175whp (129wkw).

I wanted more power and this time round I brought down a set of OBX adjustable cam gears and also opted for a twincam 16V 4-1 45mm branch.
With this setup the car made 134wkw and 198nm torque. (P.S this power is made only up to 7000rpm)

She does make more power higher up but just to be safe I've only tuned it up 7200rpm, until I get stronger rods with ARP studs.

Im still greedy for more power and I believe with the TODA or Kelford cams which has more lift I should creep over 140wkw.

thats beautiful are they ITB's?