PJay

I'm am sure you do simon, you seem a pretty clever chappy

Anonymous

never new too cold was a bad thing
best take the fridge freezer outa my bonnet then !

PJay

If you take the fridge out then there will be enough room to put an engine in

PJay

markk

iTrader: (2)

i spec and build my engines for my intended use , and an engine with a low compression ratio does not perform in the point and squirt from very low engine revs/ vehicle speed in my game , hence the high c.r (thats high- not very high) i do know of people using alot higher than me ,

a little example for ya -

any of you seen the vw/audi/skoda/seat 1800 20valve turbo engine ??
well in the seat cupra R , it puts out 225 brake with a c.r of 9.5 :1 , now go and ask the tuners what sort of power they can achieve for not a lot of money at that c.r - its in the region of 300+ !!


so i have to say - i really agree with simons statements all the way,

as for the proof of performance , ive not done anything timed for a long time - about 3-4 years ago my car did 0-60's in 3.9 secs on an older spec of high comp engine

if my gearbox can be salvaged (come on bernie - dont let me down - please !! work them miracles), and i can be arsed changing my diff ratio , then i may have another go !! - btw it is 2wd !!

Anonymous

For someone like me its all about money. Which ones the most cost effective method, not cheap, but horsepower per pound?

markk

iTrader: (2)

i also agree with dingy - torque is for me !! not interested in bhp - dont think my cars ever had any more than 220bhp at the wheels ever !!

Stu @ M Developments

iTrader: (12)

Lotta headbanging going on in here tonight guys....

EscortWRC

True...I got Led Zeppelin on the headset and I'm rockin out

OLD SCHOOL BABY, YEAH !!!

markk

iTrader: (2)

good evening stu !!

ah - real music !!

EscortWRC

Yeah.....none of this 'angry adolescent rap garbage'

REAL MUSIC....no politics, no religion, no issues....just good old ROCKIN TUNES

markk

iTrader: (2)

couldnt agree more - real musicians !! not stolen !!

Anonymous

What would any of you know about "real" music

PJay

This thread is now on a slippery slope

Anonymous

Yep PJ....hi comp rules as i said....lo comp = has beens...ie Led Zeplin.....ROFL

Anonymous

I have an appinion here....
Now the fastest sweede is frederik and his engine is an 8:1 kompression with maksimum portet head, custom intake, custom exhaust with an garret GT-42 turbo and custom cams(wild) he runs with 95ron and 1,5 bar off boost 505BHP, and 734BHP with racefuel and 2,5 bar off boost, but it has boost at 5400rpm.....
It works like HELL, what an engine.....


MY engine is 7,2:1 komp 2x bd14, portet head for low down torque and upgraded T34 turbo, and with 98ron and 1,6 bar it gives max boost at 3400rpm and holds it to the limiter...
It has the best off both worlds, and has drivability like an GRP.A rally engine... I LIKE

Forgot to say the my engine produces 507nm at 4460rpm.... and 385BHP at 6600rpm(limitor set WAY to low)

Now the point is that the engine works like you set it up, both the cams and the mapping, so go for that insted...

Sean Bicknell

Didn't the whole High comp thing start in rallying where as Mark says point and squirt is the name of the game and these guys don't rev their engines very high or for prolonged periods. I mean with a restrictor engine, I guess you can't rev it as there isn't enough air, so you may as well maximise the CR to accomodate the RPM range that you have.

Surely this is about maximum cylinder pressures, surely the cylinder pressures of both engines are the same. A High comp motor runs less boost at the top end as it has the extra compression anyway, and a low comp motor can rev harder before it reaches that maximum cylinder pressure.

I would also like to see the ignition maps for both engines and I reckon the low comp motor is gonna have more advance and more power at the top end. If that is the case, why go high comp if you aren't doing anything with it because you have to retard the ignition so much so that it doesn't det and you can keep everything cool enough.????????????

Stu???? Karl????

Sean..

BigBoost

i was going to keep my comp as 7:5,not sure now

markk

iTrader: (2)

indeed my friend , and yes i have 34 mm restrictor, my max torque is about 5800rpm !! then change gear !

stu can tell u wha the maps are like for low and high , i had a chip for low comp , and it wouldnt even run my high comp at all

but what about my engine without the restrictor , how will that be ????

at t he moment ive got plenty of low down torque (thats what it was built for ) so what will it be like if we remove the restrictor ? then have it remapped ???

ive never tried it so i dont know ??

answers on a postcard please to " yet another lowcomp v high comp post" at passionford.com

the onl thing i can say is that , i lent a turbo that ws set up for me to run 24psi with a 34 mm restrictor to a friend , who put it on his , without the restrictor, and fook me - nearly blew the bloody doors off !!!
massive boost - blew a few hoses off lets put it that way !!!

Mike Gurney

I'm with you sean - too high c:r and you will have to retard the ign loads

this business about laggy low comp engines - thats down to the turbo not the c:r

consider a high comp engine and a T4

or a low comp engine and a T2

the two will be mismatched

PJay

what about a swedish motor that runs 8.0:1 and a t6 for 550bhp?

Sean Bicknell

I know what your saying PJay and that is where my "Stu??? Karl???" comment came in. One thing I will say though is I would like to see what power that engine would produce if low comp at high rpm. I reckon it would be a more than 550BHP

I guess at the end of the day it is horses for courses. But I am also a great believer that low comp doesn't have to be shit off boost.

Sean..

PJay

I'm not saying low comp is bad, just seems all these crazy powered cars from over the water are running high or standard comp and i'd love to know how they make the power

Sean Bicknell

No I agree with you mate. I'd love to know too.

Sean..

markk

iTrader: (2)

ive driven some very bad ones !!, thats not to say that the right person wouldnt be able to cure , but some where built by a very well know company very poor, so poor that if it were mine and i had built it i would have taken it apart again to find out what was wrong with it !!

Anonymous

yeah how is that managed then as my YB can apparently only safely manage 360bhp max before det and ive been told requiring lower comp.? why cant i then employ techniques as used on the high comp high bhp engine for an even quicker motor, likewise do that same thing on a low comp motor for a monster figure a performance? Would it not just be more of the same on a lower comp engine?

Mike Gurney

what fuel do the big power cossies from norway run ?

GARETH T

good topic

markk

iTrader: (2)

it says above , pump fuel 97 octane !!

swerv

isnt all down to cost though???

JesseT

I'd assume a high-comp engine needs a turbo specced to it, propably one with a nonrestricting exhaust housing, then proper active knock-detection or ion-sensing, and a huge cooler plus perhaps added water injection. I would think the mapping is also much more critical. It would be interesting to know in detail what kind of management setup the WRC cars are running. I think those cars run crazy high C/Rs to combat the restrictor.

Mike Gurney

lots of the rally cars use motec and pectel ecu's

JesseT

Sure, but I meant more like what kind of ignition/VE maps do they use.

Anonymous

i cant believe this discuss , is still running !!!
yesterday i rememberd a m8 who built a mk3 escort , he used a high comp heavily modded 90 spec xr3i motor and slapped a turbo on it ( verry low boost ) and it was ballistic !!!
it turns out he,s still got it and its up 4 sale , apparently for less than a grand .
when i say its quick i mean it kept u with mine and my m8s stg 3 cossies up to 120 mph

GT2

The real big power cars run on Racefuel 102+ octane.

cosworth

I believe that to be true yes. But they also have a map for 98RON fuel as well, but with reduced power and boost.

GT2

Yes they have, but then they are no longer "Big power" Cossies...

spenner

do like japs do build an effecient aspirated engine then turbo charge it that generally means high comp

cosworth

There was someone asking for results achieved by the "High CR" turbo engines.

Well take a look at some of the American and Jap machinery. They`ve set som impressive 1/4 mile times etc.

But, I guess the point here is what`s better for street use.......

It`s probably just as difficult to answer as the "do you prefer the daughter or the mother" question

It all depends on what you want or where you come from or whatever (I`m not quite sure if I get it myself...)

Mike Gurney

PJay

Both, at the same time is optional but advised