High performance motor build.

Make it go fast! Kick it up a notch. Post tips in here.
So Cal Mark

Re: High performance motor build.

Post by So Cal Mark »

one of the vendors in Texas is stilling selling the 8mm dome pistons and claiming they are 9.8 to 1 :evil:
narfire
Posts: 3959
Joined: Sat Dec 27, 2008 2:14 am
Your car is a: 1980 124 spider
Location: Naramata B.C.

Re: High performance motor build.

Post by narfire »

All I've seen from IAP are flat top HC pistons 84.4mm Mahle.
I bought a set of domed years ago(Texas) , I shoud measure and see what the height is.
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
Daniel

Re: High performance motor build.

Post by Daniel »

if you post a photo of them i can tell just by looking at them if they are 8mm or 4mm domed
narfire
Posts: 3959
Joined: Sat Dec 27, 2008 2:14 am
Your car is a: 1980 124 spider
Location: Naramata B.C.

Re: High performance motor build.

Post by narfire »

Ok have a pic of these Persan supposed 84.4mm pistons
Image

Measured the skirt
Image

Looks like 8mm domed pistons. I was going to use them in another engine build,but not in the works at the moment. perhaps later.
So these domed pistons are not the best for street use? I wanted more power but still drivable in traffic in a carb'd engine and after market cams ect...
Sorry for perhaps crowding your thred eh..
Chris
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
rodman

Re: High performance motor build.

Post by rodman »

After reading this update what would be the appropriate compression and piston size to go with?
narfire
Posts: 3959
Joined: Sat Dec 27, 2008 2:14 am
Your car is a: 1980 124 spider
Location: Naramata B.C.

Re: High performance motor build.

Post by narfire »

rodman wrote:After reading this update what would be the appropriate compression and piston size to go with?
Looking back in the posts, I could not find what engine you are planning to work on...Carb'd or FI?
Regardless, I was told by people that cubic inches helps make big power. So perhaps if you can source 84.8 or even 85 mm quality made pistons....

I have the 84.4 Mahle( they are flat top) in my FI with about 10 thou taken off a massaged FI head. I run 91 or 94 octane, no pinging to date with either fuel. Noticed a bit when I put 10 liters or so of 87 octane in last year to see what would happen.
Still waiting for my winning lottery ticket so another engine build is going to have to wait.
Chris
Last edited by narfire on Mon Dec 10, 2012 12:03 pm, edited 1 time in total.
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
rodman

Re: High performance motor build.

Post by rodman »

It was FI but someone switch it over too a Carb setup before I got it.
Daniel

Re: High performance motor build.

Post by Daniel »

those are 8mm domed pistons
narfire
Posts: 3959
Joined: Sat Dec 27, 2008 2:14 am
Your car is a: 1980 124 spider
Location: Naramata B.C.

Re: High performance motor build.

Post by narfire »

Daniel wrote:those are 8mm domed pistons
Sorry to steal the thred again, but is milling a bit off the top possible? Reading this thred, sounds like unless I'm going racing, the 8mm pistons might be a bit much for a street motor. I don't want to be dealing with issues from really high compression.
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
Daniel

Re: High performance motor build.

Post by Daniel »

I've never tried it but thought of milling them down to lower the CR. what you could do is sell them and start over
buy the 4mm domed a much simpler solution imo.
rodman

Re: High performance motor build.

Post by rodman »

NAFIRE your fine I dont mind I want to race and drive on the street, if you plan on not using those 8mm pistons I can use them.
Daniel

Re: High performance motor build.

Post by Daniel »

wow that was fast lol
narfire
Posts: 3959
Joined: Sat Dec 27, 2008 2:14 am
Your car is a: 1980 124 spider
Location: Naramata B.C.

Re: High performance motor build.

Post by narfire »

PM sent :D
80 FI spider
72 work in progress
2017 Golf R ( APR Stg. 1)
2018 F350 crew long box
rodman

Re: High performance motor build.

Post by rodman »

if you were referring to me I have not gotten a pm
User avatar
TulsaSpider
Posts: 1547
Joined: Tue Apr 29, 2008 7:33 pm
Your car is a: 1978 Spyder 124 2L
Location: Tulsa, Ok

Re: High performance motor build.

Post by TulsaSpider »

I know that some people have shaved them down a bit to lower the CR
1978 Spyder 1800 make that 2L! Finally making real progress!
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