Is silvertop really that weak?

[gt20v]

i got an impression from around the world that silvertop is weak.
everyone talking about how good is blacktop.......and how bad is silvertop..even in other forum in the world...people actually ask to ditch silvertop and put in blacktop to a question on "how to mod a silvertop"

but funny thing is..Iikira Aida choose to mod a silvertop with TRD group A stuff inside.....why???why such a expensive project use silvertop?dont tell me he doesnt have enuff money to buy a blacktop.....
this really amazing..is there anything he knows that other people dont know???

i drive a silvertop soon with blacktop ecu hence MAP....going to see what will happen

[vvega]

the silvertop is attually the stronger engine the blacktop just makes more power....
look in the FAQ section on the board ther is a artical in there noting all the changes to the 2 engines

might help you

v

[vvega]

viewtopic.php?t=18953

look at that i even found it for you

v

[gt20v]

thnax for the link...i know most of it anyway...

so are you saying silvertop also potential to be as fast as blacktop?

what are needed for that??

[vvega]

the silvertop head lets it down..... thats the problem
imo spend the same amount of money on both motors and the blacktop will probably come out on top....

v

[gt20v]

thanx dude for reply..

whats the real problem with silvertop head???
ive read an old post by redmist that saying the flow of silvertop better than blacktop and its a closed chamber design too....arent that a good thing????

[RedMist]

Flow of the silvertop is worse than the blacktop. Velocity is better in the silvertop.
It totally depends on what you are attempting to achieve. I'm going to use a blacktop head and develop as much tumble and swirl into it as possible.
Several things are going to assist in regards to keeping fuel in suspension.
I'll be running it to 9.5 -10k rpm.
12.5 - 13:1 compression.
A light end fuel (aviation gas)
Valves will be offset in the port, promoting swirl.
The port will be developed to increase tumble.

If I were to develop a rally engine, the silvertop would still be the way I would head. (pun intended). The smaller ports give the developer the opportunity to direct the flow while maintaining as much velocity as possible.

[RedMist]

You ultimately want as much flow as possible through as smaller port as possible. Velocity will keep the fuel in suspension and also "pack" the cylinder with more than 100% of the cylinder volume. Think of it like a crowd of miniture people in line if they are tightly packed and traveling at speed they can't stop easily. So when the cylinder is full, they still pack yet more people in. Widen the port and give people more room to move, they travel slower (there will still be as many if not more people traveling) but when it comes to stopping they can do so easier and the cylinder isn't "packed"

Obviously the higher the RPM the more people you need and the faster they are traveling. Hence you need a bigger port for higher RPM.

Hope that didn't confuse you more.

[Adamal]

I actually think thats a very good explenation, Redmist.

[Lanius]

I actually think thats a very good explenation, Redmist.

agreed ... good stuff

[RedMist]

Cheers Gentlemen. It gets a little more complex when you consider the valve closing and pushing a small number of people back into the port. They take up a bit of slack.. but tend to push back up the inlet track. Hence the spring action of .... you guessed it... Helmholtz!

[gt20v]

tedmist,a really good explanation.....
since the velocity is good ...why can make the port bigger for floe but at the same time keep the velocity as usual?
make the start of the port a big bigger and maintaining the velocity design of it??

just and idea. .feel free to correct me...

[KinLoud]

And if you have a turbo... just think of the turbo a HUGE SUMO WRESTLER pushing heaps more people down the intake and into the combustion chamber.
Just like they do on the Tokyo train system during rush hour.

("what trim sumo do you have?", "ahh, I have a 320kg trim sumo. It's great, good top end in the middle of rush hour and bugger all lag")

Ken
Ham
021 408 863

[92GTApex]

Brilliant...

Logan