Im going big revs........ discuss

[Sleeper_Avant]

Right, im a self confessed rev-a-holic
previous marques i have built were built with higher compression boost engines but higher rev limmit,

the "AAN+" i plan to build will match the long line of builds completed hopefully,

would the italian spec 2.0 (NM?) crank be better for higher revs with custom pistons/rods?

or is the 2.2 crank suitable for say 10-11,000 rpm?

there will also be an ultimate spec head with monster cams, suggestions on suppliers?

Head by Ric Wood CNC head? JP? anyone else?

What cams are used for monster revs?

tried the usual suspects like Jonus and Dahlback but no reply

any suppliers for propper quality oil pumps, Titanium retainers, and any other gubbins would be greatly appreciated please

Dry sump is also a direction now as im going all out on it, RWD, moving engine back approx 4 inches and down about 3 inches if all goes to plan

Sean

[campbellWS]

Hope this helps with looking for uprated bits and bobs!

http://www.rosten-performance.com/

[driftin jo]

Why such high revs ? 9500 rpm will get you 1200hp with a big turbo and a power
band from 5000-9500, even this is going to be expensive, rods pistons, dry sump etc.

The revs you are talking about are more for NA tunes than a turbo motor,
with a turbo motor you need strong heavy con rods to take high torque loading
to make power, this sort of rod does not lend itself to very high revs, unless of
course you phone Pankl and have them make you some rods at ~£1000 each that is,
then you need some pistons that wont tear them selves apart at those revs and they
will be a similar price, do you fancy £10 000 for rods and pistons ?
Then these is all the other stuff you would need, you talking silly money,
and for what.
How much power do you want ?

[JP]

Turbo charged cars struggle to rev above 9500 purely down to exhaust backpressure unless you run a silly large hotside making he car practically undriveable other than track use.

Other things to keep in mind:-

Any gear driven oil pump starts to cavitate at high rpm which in turn means the oil becomes incapable of supporting the big end bearings on the downstroke. So for any sustained rpm much greater than 8000rpm you will need to upgrade to a dry sumo setup.

Hydraulic lifters cannot cope with sustained high rpm physically pumping themselves empty. Again any sustained rom over 8000rpm you want to go solid lifter.

This brings you onto cams where if going solid lifter to sustain rpm you will need cams to support the higher end of the rpm band. Either catcams or schrick do well in this department.

This then leads onto valve train, increased spring strength is required to prevent valve float at increased rpm and exhaust backpressure. These will need to be individually shimmed for desired seat instal poundage. Titanium retainers come of use here to reduce weight to reduce likelihood of float once again. There are advantages ay v high rpm to also stick with stock size valves and in some cases even reduce the size of the exhaust valves depending how high a boost one wishes to run and what sorry if end rpm target you go to.

Cylinderhead will need to be machined and ported to suit whatever cam and rpm profile you choose, this rules out cnc heads as they are a one combination works wonder. Much like a generic map when chip tuning.

Bottom end crank rod and piston configuration will vary depending on the final use. For example I would choose a different stroke and rod ratio for an engine that is used for drag racing where peak rpm is momentarily reached. Compared to a roundtrip round which moves up and down in the higher end of the rev range vs say an oval track car which sits at very long sustained rpm.

Depending then on the choice of stroke rod and pistons configuration it would dictate how the block is prepped for increased strength.

Long and short of it if done properly you wont see much change out of £12-15k for a long block that is bullet proof for 9500rpm. To go over that 25k+

[Sleeper_Avant]

to be fair i understand the costs involved as i built many gpN/A/WRC cars in a previous job, and fitting 50/60/70+ thousand pound engines and gearboxes comes second nature

power, well, over 800 with no particular figure or power band as a target.

I understand that i obviousley need mechanical lifters and titanium retainers/springs and dry sump etc
I have built 3x high compression 8.8:1 1870cc YB turbo with a batch of Farndon crank and rods i had made that revved to 9600 for a customer and my own was 8800 as i didnt own an oil drilling company lol

Turbo choice is again understandable and will always be this cars Achilles heel but as you said is going to be purely a track slag/drag use but that can be specced when i am 100% certain on the rest of the engine but yes it will be a huge hot side probebly above 1.00AR no doubt, wont be the first time!

i struggle with suppliers more than anything since im out of the water with these 5 pots, anything Jap or Cosworth then i dont have a problem,

9500 isnt a million miles away from the magic 10k revs, but once that 9000 threshold is passed, again, the bar is moved

Im not an engine builder by trade although i do build engines, but i will be outsourcing this as im totaly aware of what is involved and am not looking through rose tinted glasses by any means.

ive spent enough money on shonkey old Fords for too long and this A4 is my unicorn, if i dont build it now while i have money coming in, i will never get it done.

[terrybullwon]

I don't see this Happening sorry

[Sleeper_Avant]

ok.

[driftin jo]

You want big power , buy this,

http://www.ebay.co.uk/itm/CHEVY-Smal...29543392682697


, fit a big turbo, or two, remap, voilà 1000hp, simple cost effective, reliable.

[Sleeper_Avant]

Terrybullwon, i think pasing judgment like that when you dont know anything about me is, well frankly very rude!

i dont want a V8 in my A4, but i will have an 80`s Camaro IROC at some point

i was told a 5 pot wont fit an A4 about 3 yrs ago by most people on forums and in the "scene"......... LOL i should give up incase i run into problems i think

[JP]

Suppliers of parts is easy there is plenty out there of the shelf for sub 10k rpm.

Would never use Farndon again biggest bunch of :corey: going ordered a crank in December and is now coming to end June and still haven't got it customer is fuming as we've missed the whole season. Paid in full in april when it was ready to go for nitriding.....if we hit july will be going to small claims via trading standards due to breach of contract which was 8-12weeks.

Anyway back on topic. Only limit realistically is money but I'd still set target rpm at 9500rpm simply so you can go with of the shelf cams. As for horsepower that's neither here nor there the end type of use is with regards to stroke configuration.

[Mcstiff]

I keep hearing, from some motorgeek posters, how a tall deck I5 with longer rods would be a good base for a high RPM build. May be a good place to start.

[campbellWS]

I don't see this Happening sorry

Why not?

Chap on mate and prove them all wrong!!!

[Sleeper_Avant]

Well thanks for the info on Farndon JP, same with us Ford lads thinking Field Motorsport are gods, Jogi prooved that wrong......

yes anyway......... ok 9500 for off the shelf stuff, worth a ponder defanitley but as said cost isnt the biggest issue, but i cannot stand waiting for bits!
power is in no way a target its purely top end power band for specific track use

[Sleeper_Avant]

Campbel, i dont take any negative comments on board like that, like i said 5 pots dont go into A4`s, its impossible............... but im sure Acidburn can vouch that my AAN A4 accelerates very swiftly, for an engine that doesnt fit lol

Mcstiff, i have searched lots of high rev I5`s but they are very secretive unfortunatley

JP, id be happy for an in depth chat if you were interested in some work?

[terrybullwon]

Sorry don't take offence I just think after doing this my self there are alot of better ways to skin the Rabbit.

Here is Jon Jonus's number 00 47 926 07 078