has anyone done, or know any info about boring out a dohc engine and if so what how much should i go and what size pistons shouls i use thanks

 

well depends what are you doing N/a or F/I? what are your power goals with your engine, what is your budget? how beat up is the engine,

 

i was just wonering ive got a gt-x engine swap from the j-spec gt-x and i found 85mm pistons. i know stock is 83, just wondering what i could do thanks
heres the kit i was looking www.importperformanceparts.net/?source=looksmart

 

boring over to acheive what?? a better cylinder bore surface?? greatr idea!! if your intentions are to increase displecement, dont waste your time. You might be able to bore to like 1.9, but youll acheive little gains in return for yuor great effort and expense...save boring over for the V8 guys...they have much thicker cylinder walls and have much more clearance and tolerance for such thins

 

Yeah, what he said. The one thing I found out boring a block out to it's maximum: It made no extra power and when I went to refresh the block with forged pistons and rods I found out the block was trash because I had run it out too far and had no more room to square it up.

Long story short: buy a stroker kit, make more power.

 

so you think its not worth it. thanks it was just an idea to increase displacement and hp. i appreciate the help. ride on and slide on, sideways that is

 

if you're looking increase displacement and you've already got the motor disassembled why not put a good forged stroker kit in it? It would add an overall sense of power but nothing along the lines of adding a small turbo kit.

You may do well to get a wagner turbo kit for your 1.6L motor. He's the only one making them that I know of and they make gobs of power. I think he baslined a 1.6L and it made like 78-80whp.....then with the turbo it was 175whp. I may have the cars mixed up but the numbers are right. Either way.

 

im 1.8 turbo and intercooled already thanks ill look in to the stroker kit thanks again

 

oops....I need to pay more attention!! Sorry!

 

its cool thanks

 

85mm is the max spec for the engine

 

I've heard that like only 1 in 10 BP blocks can be bored anyways.

 

Well, its a GTX, so its turbo, why take the hard way to moddin when there are better paths to take than overbore. Overbore is more a thing for naturally aspirated.

Me, it would be, bigger turbo according to the displacement of your engine. People think that the bigger the turbo the more is goin to run. Go with bigger intercooler for more efficiency.

What about fuel pump?
Injectors?
APEX or GREEDY computer systems.

Try to work with the exhaust shell, change the exhaust blade to a bigger one and port the exhaust shell so the blade will fit. This street mod makes the turbo look stock when in fact the blade and shell combo has been modded.

A .63 exhaust shell trim is ideal. I am not familiar with the turbo you have, is it ball bearing type? can it be changed to BB?

This little hints give tremendous gains.

What we do back home is get the RX-7 second generation turbine, remove the huge exhaust compressor, and install a .63. It will not fit into the turbine because the holes in the new .63 compressor are small. Take it to a machine shop and tell them to bore the exhaust to the size of the turbine exhaust blades. This is one of the best combinations for 4 cylinder blocks.

Open to bigger diameter the size of the in/out of the intercooler.

I would never touch that block if it is running good right now. NO MACHINE SHOP can assimilate the factory specs and if it is not broken dont fix it.

 

 

well ill scratch boring off my list of things to do to my new DOHC engine (its in the works while im running with my SOHC)