what forged pistons
- Thread starter turboflow
- Start date
Ah, he will be from some far off land with "magic" dynos I believe
typical, always have to resort to talking down to persons that are not from the uk
only UK dynos work right, i forgot
now emailing my contacts in australia, jamaica, guyana and backyard productions in the US to tell them all that their flat top CP pistons are no good and the dynos showing near 300whp are all wrong cuz they are "from some far off land with magic dynos" ie. not in the uk
u guys really do amaze me with this low thinking, it is one thing to state facts, but another thing to base ure comments on bias and one-sided thinking, have a nice day sir, continue in ignorance
Dave@TM-developments.com
Trader
dantheman
Member +
flat top pistons will be fine at 250bhp...its not dependent on power anyway,boost and igntion and setup is what it boils down to... i ran 2bar on my ross flat tops in my gti-r for quite a while and it got driven hard, no probs with them... although i prefer to run dished wiseco's in my 4e as i like to have lower comp for safety as i run a fair bit of boost ( im running a large turbo so im not really loosing much low down power by having a lower cr anyway..)
dished are preffered though as the combustion is contained in the dish, and not on the surrounding area's ie head gasket..
if you wanna keep lag to a minimum and retain some low down response id go for flat tops mate (in my opinion)
(search for the thread for more info)
although i prefer to run dished wiseco's in my 4e as i like to have lower comp for safety as i run a fair bit of boost ( im running a large turbo so im not really loosing much low down power by having a lower cr anyway..) dished are preffered though as the combustion is contained in the dish, and not on the surrounding area's ie head gasket..
if you wanna keep lag to a minimum and retain some low down response id go for flat tops mate (in my opinion)
(search for the thread for more info)
speedvision
Member +
the stock piston just has a 1cc dish which is almost a flat top piston....i fu compare a flat top with a stock 1cc dish u will see what i am tlkin about..
companies as i got to believe make them flat top as they are easier to make and much more cost productive ...they make up for the 1cc compression lost in the valve pockets.........
it is up to you and ur engine builder what u want to use but keep in mind both flat top and dished forged pistons are very strong...
200-250 bhp u wont have any problems with flat top and u will also get a better response off the turbo as compared to the lower compression one..
most pple like response hence why they go for stock compression as opposed to lower ones
sam
companies as i got to believe make them flat top as they are easier to make and much more cost productive ...they make up for the 1cc compression lost in the valve pockets.........
it is up to you and ur engine builder what u want to use but keep in mind both flat top and dished forged pistons are very strong...
200-250 bhp u wont have any problems with flat top and u will also get a better response off the turbo as compared to the lower compression one..
most pple like response hence why they go for stock compression as opposed to lower ones
sam
Dave@TM-developments.com
Trader
Are the CP pistons not 9.0:1??
Custom made to our specs by CP Pistons, engineered with custom features to enhance performance and strength. This is a multi-fit piston. Nominal compression ratios are as follows and can be adjusted with gaskets, deck clearances and head modifications:
3E = 9.3:1
4E = 8.0:1
4EFTE = 9.0:1
5EFTE= 8.5:1
Custom made to our specs by CP Pistons, engineered with custom features to enhance performance and strength. This is a multi-fit piston. Nominal compression ratios are as follows and can be adjusted with gaskets, deck clearances and head modifications:
3E = 9.3:1
4E = 8.0:1
4EFTE = 9.0:1
5EFTE= 8.5:1
5E is more like 9.5:1. That is in my 74.5mm 5E anyways. But the are supposed to be 9:1 in the 4e as u stated...............
????
Dave@TM-developments.com
Trader
So if Toyota spend x amount on development of the 4e to arrive at a comp ratio of 8.2:1 on a CT9 @std boost why would you want to raise it to runner a bigger turbo and more boost. Are you lowering comp by another method or using race fuel?
that is why i made this
http://home.tiscali.nl/paseo_style/turbo/projecten/test/test11.html
i hade the same problem with my preresearch to my current build
speedvision
Member +
Dave@TM-developments.com
Trader
lol, dont know, dave got them in for me :haha:
Dave@TM-developments.com
Trader
:rockon:
i had a other formula picture, but can't find it.
Vc= Vs / CR - 1
b = cylinder bore (diameter)
s = piston stroke length
Vc = volume of the combustion chamber (including head gasket)
Vs = displacement
first calcualte back the combustion camber witch gives you the head cc's
add the new values(head gasket, pistons) to the head cc's.
don't you think it is correct?
Last edited:
i am no expert as i am the one who made the post but i am still swinging towards dished becuase when explained to by dave it made perfect sense if you blow something up directly next top a gasket its never going to do it any good. do carry on with the sarcasm and daves witty replies its keeping me amused at work at this ungodly hour. lol
cheers
owen
cheers
owen
because toyota didn't expect me to take out their stock, untuneable ecu and put in a microtech or megasquirt or power FC
and it should be obvious why i would want higher compression to spool a bigger turbo..............and btw the compression isn't lowered with any other method and the fuel is camel piss with water/methonol coming in after 8 psi