frog

Couple of cars featured in FF this month claim 400bhp and more on 20psi.

Is that right ?

I would have though you'd need more than than, or, is it because a larger turbo will flow more air in the engine at a given level of boost

CossieRich

iTrader: (1)

Rods is 500bhp at 1.5 bar Greg

Ryan

as said 400bhp is more than possible on 20psi.

It all depends on the turbo and engine work.

frog

ok, so, bigger turbo = more air at given boost level = more power in simple terms.

I'll go get my hat and eat it

Anonymous

Extremely possible, and in reality its actually far more to do with the engine than the turbo.

Bare in mind you can make over 300bhp from a cossie engine on ZERO psi of boost if you know what you are doing and have fairly deep pockets.

Anonymous

Thats over simplified, boost is a measure of three things really:

1: How much air the turbo is flowing
2: How well the cooler is working (cooler air is denser so the pressure drops back)
3: How crap the engine is at swallowing air, the more restriction in the head and the more boost you will see

Stu @ M Developments

iTrader: (12)

Essay time:
https://passionford.com/forum/viewtopic.php?t=24009

Ginge !

stu think chip made it very dummy proof that a idiot like me understands

but essays are fun,,,, now wheres that cossie build one



as i need help

Chipperx2

More to teh fact, have you seen teh girl on page 167, holy shizznick.

and shes Scottish

peteh

iTrader: (3)

Anonymous

Stu is referring to something slightly different to me in his essay, im concetrating more on mods to the engine to get more power at the same boost, he is concetrating on a larger turbo.

My way of doing it is kind of better than the way he documents there as it results in less movement of the boost threshold, but in reality people building these sort of engines tend to do both things anyway, like madRod for example

Essentailly the change stu documents there is cause the turbo places less resistance against the engine emptying the exhaust gasses, where as what ive been mentioning is more about the engine having less resistance to swallowing air from the turbo, obviously a bit of both is even better (Stu knows this of course, his essay wasnt saying that is the only way to do it, he was just detailing the effect)

MK5RST

If your gonna run a low boost and expect big power then you will have tp run quite high compression wont you?

Stu @ M Developments

iTrader: (12)

Emptying and swallowing efficiently makes for a decent VE indeed dont you think chip

Ginge !

you are mistaken it whats boost is i belive, boost is a measurement of presure and not flow, aim a 18 foot tube at a wall and force 18 psi of presure through that, the wall fall down

add 18psi through a straw and ya get a breeze

what you taking about is low presure/flow high comp engines

where talking about 20psi engines that flow alot better and so 20psi is flowing the same as as 30 psi on another engine but the 20psi engine is more efficiant

think of air as liquid, measure it in presure but ya want the volume so a pint of air in a beer glass will all fall to the floor instantly, it a bottle neck the end and it will take longer , have more presure but will actually flow less fluid per second

btw im not the smart one here so i prob will be corrected but thats how i understand it

Ginge !

thats a essay and a half and made me eyes go funny at this time of night

ill read it in the morning

Anonymous

mk5rst, No you dont need high CR to make the power, it will only make a few % difference on normal fuel even if you raise it quite a lot.

Stu, best way to build a turbo engine IMHO is to largely treat it like an N/A one in terms of most of the spec, like head flow and valve lift, but obviously a bit less lift on overlap and a bit of a drop in CR.
Using the least amount of boost possible though is the way to go for sure

Stu @ M Developments

iTrader: (12)

It must be geting late... read my comment again Chip

Anonymous

Stu, i read your comments, i was agreeing with you not going agianst what you said

RSKim

Nic asked me if I'd ever seen one of your essay's on sat I hadn't but I have now and wish I hadn't Its mega long and I've got this urge to read it

Muska

think stu was using a bit of inuendo

Stu @ M Developments

iTrader: (12)

Thank you Musta, im shocked and saddened at chips inability to read such content given his usual filthy mind

Anonymous

I was trying to keep it on topic with engines, cause you said the other day you wished there were more engine threads on here, so i was giving you the benefit of the doubt, LOL.

Muska

no worries Ste @ M Developments, dunno whats wrong with him!

CossieRich

iTrader: (1)

Sort it out Chip. Filth is always at the forefront of your mind.

frog