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Hello:veryhappy, well im restoring a Manta A turbo series replica from a 71 manta A SR and im doing it in a tight budjet and in Portugal we dont have much parts around.
my question is: i was searching on the web and i saw in diferent specs websites that my car has 9.0:1 compression ratio and in others 9.5:1 and in the turbo i find also the same problem that some websites say 7.8:1 and others 7.6:1 os compression my bets goes to 9.5:1 and 7.6:1 but im not sure:banghead:. also some guys from manta owners forum said to me that to lower the compression i could make some kind of chamber in my pistons to lower compression but i dont know how much probably 1mm? i did this calculations..

7.8:1 = -1.7pontos dos 9.5:1
da 0.085 = 2.159mm

7.8:1 = -1.2 pontos dos 9.0:1
da 0.060 = 1.524mm

7.6:1 = -1.4 ponto dos 9.0:1
da 0.070 = 1.778mm

risse motorsport exist until 2mm

well i really wish to know the real numbers to buy the gasket and what to tell the guy that is going to machine my pistons. thank you very much for any help you guys can get me :cool:
 

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I wonder if you could just use a set of the later year (here in the states) low compression pistons that had the big scoop out of the top. They were 7.6:1 compression compared to 9:1 for the flat tops.
 

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yes but anyone knows how much do i have to drill in the stock pistons with a 2mm or less head gasket? cuz i dont find info anywhere and i dont know much about the subject all i find is how to calculate compression ratio and stuff like that... new pistons is a good idea but they cost more then a new engine..and im in a really tight budjet...and i want to get marry with my car driving me!!! lol
 

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Turbochrager Compression ratio

Hello:veryhappy, well im restoring a Manta A turbo series replica from a 71 manta A SR and im doing it in a tight budjet and in Portugal we dont have much parts around.
my question is: i was searching on the web and i saw in diferent specs websites that my car has 9.0:1 compression ratio and in others 9.5:1 and in the turbo i find also the same problem that some websites say 7.8:1 and others 7.6:1 os compression my bets goes to 9.5:1 and 7.6:1 but im not sure:banghead:. also some guys from manta owners forum said to me that to lower the compression i could make some kind of chamber in my pistons to lower compression but i dont know how much probably 1mm? i did this calculations..

7.8:1 = -1.7pontos dos 9.5:1
da 0.085 = 2.159mm

7.8:1 = -1.2 pontos dos 9.0:1
da 0.060 = 1.524mm

7.6:1 = -1.4 ponto dos 9.0:1
da 0.070 = 1.778mm

risse motorsport exist until 2mm

well i really wish to know the real numbers to buy the gasket and what to tell the guy that is going to machine my pistons. thank you very much for any help you guys can get me :cool:
Turbochargers, unlike superchargers, are not compression sensitive to a point.
9-9.5 to 1 is well within the operating range of the turbo. The larger turbo you run-the more air you push through the engine. You may need to run bigger jets or a higher CFM carb. but unless you are planning to add nitrous-oxide into the mix you will be fine with just using a higher octaine gasoline.
 

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Discussion Starter #6
cool

Turbochargers, unlike superchargers, are not compression sensitive to a point.
9-9.5 to 1 is well within the operating range of the turbo. The larger turbo you run-the more air you push through the engine. You may need to run bigger jets or a higher CFM carb. but unless you are planning to add nitrous-oxide into the mix you will be fine with just using a higher octaine gasoline.

thanx alot :)
 

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Discussion Starter #7
Wow, a turbo Manta for a wedding car.

You must want to get to the honeymoon hotel FAST!

:lmao:
hehehe that would be great but the honey moon is in croatia.. even fast it would take me 2 days to get there from portugal and looots of money to gas heheh but it would be awsome!!!!:cool:
 

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Discussion Starter #8
Turbochargers, unlike superchargers, are not compression sensitive to a point.
9-9.5 to 1 is well within the operating range of the turbo. The larger turbo you run-the more air you push through the engine. You may need to run bigger jets or a higher CFM carb. but unless you are planning to add nitrous-oxide into the mix you will be fine with just using a higher octaine gasoline.
im choosing the turbochager now.. can u give me a moe accurate idea of the best turbo to install without blowing my engine up? hehethanx again
 

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im choosing the turbochager now.. can u give me a moe accurate idea of the best turbo to install without blowing my engine up? hehethanx again
A good engine management system should be your first endeavor.
Yes I've turbo'd and blown(supercharged) engines with 11:1 CR before with laughing gas.
The stock driveline will not handle the torque or HP!
Look Maw no teeth
 

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Discussion Starter #10
A good engine management system should be your first endeavor.
Yes I've turbo'd and blown(supercharged) engines with 11:1 CR before with laughing gas.
The stock driveline will not handle the torque or HP!
Look Maw no teeth
ufff! bad bad thing to happend...well my idea is not pushing over 200 hp so my stupidity says its going to be ok... thats also why i want a turbo that dont push too much.. so if u know one ''safe'' somebody said to me garret t25 but its rare to find... at least in here.. i need it more to know the flange so i can make the damn turbo adaptor (like the original turbo manta) the original turbo was a holset i think but i was searching...uff they are more expensive then to buy a complete engine... bahh people also wants to get rich with a piece iron... and more lucky news one of the bolts that is holding the injectors broke inside!! more fix fix fix... but the doors covers are almost completed when the first one is perfect i send pictures :)
 
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