well thought out then pal but had you not planned this, it would have been incorrectly speeced for your engine as a whole

 

Hey Mark, how goes it?

Anyway, in this "real rallying world" of high comp engines, what's the score with reliability?

How's your engine?



Joke by the way

 

The thing is that rally engine has only so much to last as budget and regulatin allow it. In case of WRC it's 2 events so maybe 600 stage km, 3000km's alltogether.

 

hi rich engine is fine pal , thanks for asking pesky water hoses

 

not in my budget pal , it has to last alot longer than that. i dont have unlimited budget.

 

Yep I know.

I don't know about Uk clubman spec cars as they are completly different spec from FIA regulatons. I know that Grp.N cars engines here last about 3-4 events, sometimes 6, gearbox only ~2. At least this is the point when it need to be taken apart and checked.

 

Nothing WD pasted in is very complicated its just too much info at once to bother taking in.

Its off some site like "how stuff works" or something like that probably.

Maybe he will post the original link so that you can read it with formatting and see how simple it is then!

----------------------------

I would but I cant remember where it came from !

I copied it into a word document and kept it for referance

 

it's all over the web, if you do a search using a random sentence from the middle of it you'll find it in many places.

top of the google search that i did (http://www.google.co.uk/search?hl=en...e+Search&meta=) was

http://vettenet.org/torquehp.html

 

i originally asked AVA to build an engine that would run 450 ATW.

my engine made 400 after mark mapped it, but he and alan(ava) both think there is more power in my set up as it is(t4 instead of gt30-35).

reckon another 20 hp could be found on existing set up with the othere 30 coming from the bigger turbo..

only thing really stopping mfrom doing it the "hidden" costs, i.e would defo need a big tooth box(Ł1700) more mapping(Ł300) on top of the bigger turbo and new manifold/wastegate.(Ł2000).

happy with the power just now and the reassurance that it should never det in this spec.

next step is an optimisation on the rollers and after that maybe the big turbo...

time will tell

 

Phil,
If you think that, check your turbo / exhaust manifold after a few thousand miles . Just put an EGT gauge in your car and you'll shit yourself .

Mark,
I've just checked and it is 35lb ft at 7k . As Azrael has explained (quite clearly ), there is a HUGE difference where the restrictor is put. It does not matter if you have the billion pound budget, you can't exceed more than 320bhp through the current restrictors - not without defying physics or cheating*.

*See Toyota back a few years .

Anyway nice discussion .

 

Mike Rainbird I'm told that you can get a couple bhp more then 320 but not much. Most of the difference is due to getting higher heat efficcency and using oxygen which is bound in fuel particles. But it won't make much difference.

I don't know if anbody experimented with this a lot but I would expect that with "bilion pound budget" thry wuld still make zilion horsepower if restrictor were fittted bedind the turbo.

 

might well be 35 @ 7k, you find me a rally car that makes peak power at 7k most make peak torque by 3k and hold it to 6-6.5k, so that makes us back around 20 ft/lb, so what where we saying about race fuel, yes there is an advantage, but in the case of the engine you quoted, theres no real differance in peak torque, the torque figure moved up in the rev range, as did the bhp, the gains are what ?

and the current rally cars are knocking on the door of 340 btw

mike you stick to your 'specialised' subject, i will stick to mine, you have a road car, i have a competition car. if i want a road engine i will come and see you, if you want a competition engine, you come and see me

 

markk i though most WRC/GrpA cars upshifted below 6k rpm so peak power mustbe even lower?
I know that Grp. N Impreza N-11 from Prodrive had maks power around 4500rpm.. almost like diesel... damned 32mm restrictor :-(

 

@ Markk

Mike------

 

So why do you keep commenting on the effects on a restricted rally car engine as if they are going to apply equally to an unrestricted road engine then?

Dont get me wrong, i find your information interesting, but it does seem weird that you cant seem to notice just how much of the charateristics of your engines are there because of the restrictor.

If you look at what toyota did without the restrictor (more power higher up the rev range) you will get a glimpse of what would happen if manufacturers were allowed to remove them.

 

Wasnt group B a glimpse at what manufacturers could do if there were no restrictions and limits, bearing in mind audi tested an s1 quattro with over 1000bhp

 

rewind to the beggining of the thread and have a look at the title, my engine is mapped for with and wthout restrictor, mike then proceeded to say that without race fuel it wont last ten mins its good to read pal

 

markk but your engine would be completly different if you designed it to run only without restrictor.

 

But your comments since then have all based around the characteristics of rally engines which are specced FOR the resitrictor.

Your engine is a restrictor specced engine that you then run without the restrictor and have mapped it to make the best of a bad job in that respect.

If your car was being designed for road fuel and no restrictor, then it would either be lower CR or would make peak power higher in the rev range, or a bit of both.

You seem to be taking your own engine spec out of context
Just cause it copes ok without the restrictor and on normal fuel at that CR you seem blind to how much different it could be in those circumstances if the rest of the design wasnt compromised for such a specfic competition use.

 

We were replying at the same time, yours was much more to the point though.


MarkK, Even Stu who maps your engines designs his high milage normal fuel non restricted road engines doing all the things that MikeR is talking about, do you think thats cause Mike is correct, or because Stu is stupid?

 

i have specced many good road engine pal, and the cr would nto be any lower than in the 9.0's , yes the restrictor does make the torque curve very early in the revs range, and without it its further up in the rev range, so im not seeing your point ?


the original thread still stays true.

if i was speccing an engine for over 500bhp it would be completely differant, for a start i would decide what torque i wanted and for what application it would be used, but take my word i wouldnt fuck about in the 7's for compression

 

markk but if you specced rally engine without restrictor wouldn't you make it as much power as possible for your budget? Probably YB without restrictor would be in 600-700bhp range, maybe slightly less for more reliability.

 

If Markk could drive a 600-700bhp cossie to its potential on a rally course I would be fking amazed. Not dissing your driving skills markk as I bet you're a million times better than me. But come on. Whats the point in that much power.

 

89XR2 in grp B days they found use for that in much lighter cars then the Sierra. When you fighting for parts of a secondd you always want every horse you can get. Grp.A Escort by RAS motorsport used to have wipers on uniball bearings to save on power!!!!

 

My point is if you were designing a road car to make good torque at low RPM on big boost you wouldnt use over 9:0 CR on a YB.

If you do, then obviously you know something that none of the other people building YB's seem to want to take notice of IME.

 

I beleive Scott @ Jullian Godfreys runs 9.2-1 on 9.5-1 cant remember and has a dynoed 500bhp on pump fuel in a ROAD only car..RELIABLY

 

At moderate RPM?

I very much doubt it!

If what you say is true, i bet its making peak power well over 8000rpm!
And YB's dont last long if taken past 8000 reguarly.

 

havent read all the thread,,, but i just wanna say one thing

PCP

 

Indeed!

And EGT!

 

...oh revs to like 9k by all accounts...but its a YB thats built for it

 

I know they did but current wrc cars are FASTER on stage than the old group b cars due to better grip/brakes etc. The speeds people would be doing in wrc cars if they were allowed unlimited power now a days WOULD be suicidal. Most of the old Group B drivers were scared driving their cars, well with the exception of people like stig who openly admits he wasnt afraid to die rallying.

 

Your idea of "does it reliabley" and mine are different i suspect.

My idea of CR / Torque / Rpm / PCP and their interaction and Julian Godfreys are obvously exactly the same though.



Its weird phil you seme to have learnt half of the story of CR and its effects, but you are completely blind to the other half!

 

Longer?

and secondly can someone please change the thread title

 

Gareth, oops, yes as you can tell from the rest of the sentance i meant less time, not longer.

Shows no one else bothered reading it properly though

"spot the deliberate mistake"

 

this is a classic case of people who 'do' and people who 'read'.

im not going to waste anymore of my time, i dont have to convince myself, nor do i need to convince aload of people who i dont know, will never meet, nor will i sell an engine to you, you obviously disagree with something that has been proven to work, i can spend all day talking about the 'theory' the reality is, unfortuantly for you guys , some what differant.

 

what do i win mate?

 

Stu could post exactly the same reply to you about his usual road engines he well, which also work.

Its all about what you want from an engine at the end of the day, i build engines of different specs for different things, for example my engine ive built for my nova should make best part of 600bhp and is 8.25:1, so if you think i dont agree with you on a lot of what you are saying you are wrong, but i do think you are choosing only to say the half the story that suits you despite the fact you probably know a lot more about CR/boost and PCP/timing than you are letting on here with your seemingly blinkered replys that everything has to be like a rally engine!
You havent even mentioned economy or engine lifespan, and those are things that most people rate quite highly on road engines, even fairly big power ones!

 

mark the only reason why theorys fail is something is missing from the equation

 

LOL, good point!


Sadly though, personally i wont EVER know the whole equation when it comes to engines, as thats the nature of learning mainly from doing things, a lot of the decisions you make you do so subconsiously without REALLY understanding the maths behind them, you might know some of that theory, but never the whole lot.

I do not have access to any books that give me enough data to work out the optimum CR for my engine, so the fgure of 8.25:1 i have come up with is basically my "best guess" based on other engines, i like to feel its an educated guess, but it IS still a guess really.

Without a budget of millions of pounds to build dozens of these engines and throughly test them i have no choice but to settle for an approximation to the best solution as its beyond my means to get the perfect solution!

 

like i said, im not going to go into this anymore, as the people now doing the discussion, know everything 'they' need to know anyway. we are all capable in building engines ( generally) building performance engines is completely differant, building performance engine and giving WARRANTY is something you need to look at that is all i need to say.

there is a big differance on how you spec a motor for its use, im sure ive said that, i dont have a 'blinkered' approach, i have a favoured method, which eliminates certain properties of other peoples builds that i dont like.
there are far too many people who follow the sheep, i.e the tried and tested, and will stick to it because theyve never done anything else or been fortunate to have the time/money/ability to do the nessecary R+D required to make this reliable.

longevity is a key point to my rallying budget believe me.