DamoM

Well after having had my car rolling roaded hoping to see close to 500 bhp I was disappointed with the result!!

I had effectively followed every bit of advice possible and had a remap by a reputable company. They were convinced that the car was dong the power but as they had not built it (it is GpA spec everything) they were unable to gurantee that it was.

I took the car to a dyno pack dyno to get the power figures verified and they came up with exactly the same figure. The power comes in at 4300 rpm (when the boost hits it's stride ) and peaks at 6200 rpm, then tailing off quickly.

You can see from my signature that the car has all of the ingredients for big power but it ain't happening!

I spoke to the mappers and they were a little puzzled that it hadn't produced more and pointed to the cylinder head as being the problem. They claim that the boost had to be held back at lower revs as the head couldn't handle the flow. They also said that a standard head will not allow and engine (regardless of other mods) to produce more than 400 bhp.

I am unsure as to whether the head on my car has had any work. Trouble is, I am looking at £1000 + VAT for an exchange ported head PLUS the cost of the valves and springs. Then I have to pay extra for this company's cams....

Thing is, I don't want to start shelling out even more dough, when I have already spent thousands to get to a point that is not that much further than I already was at. Some of these firms are very good at telling you what you want to hear and then charging you for the privilage only for you to have to return for those endless extra tweaks to get you where you wanted to be in the first place...I have been here before and that i why I wanted to get it all done at once without doing it piece by piece. Thing is this method doesn't seem to have worked either!!

Has anyone got any thoughts on the above or any experience as whether the std head really is the bottle neck in this type of application?

Also, has anyone any idea where I can get a head ported to stage 3 spec (26mm inlet and 25mm exhaust) for less than £1000 + vat exchange?! Any ideas also what cams are best recommended?

rapidcossie

who build engine and who mapped it?

DamoM

I don't know who built it but have all of the receipts for the parts and one receipt for the buid with a guy who looks like he was a one man band.

I will PM you with the mappers as I have seen people havew their threads removed for naming names on here before (I am sure you can guess for the reasons why....)

bud-weis

just name them,but doesn't matter who mapped it .....nobody can get 500bhp on standard head and cams

rapidcossie

got your PM..

the person who mapped is usually very good.

you need to find out what spec the head and cams are as they are the most important part of any high power engine.

what rolling road was it at?

do you have a graph?

all the parts seem to be there on your spec

DamoM

I take your point Martin. They are not guilty of not acheiving what is seemingly impossible, simply that they didn't tell me....

I would rather not name them as I am sure the thread would get removed and that I not conducinve to me getting the benfit of some shared experience and infoirmation from fellow cossie owners!

DamoM

Yes, they were recommended to me so I know they have a good reputation.

It is going to be difficult to get the spec of the head and cams without pulling it all apart, at which point I think I might as well get the head rebuild with new bigger valves etc so that I KNOW what I have. It might be that the valves are bigger than std already and that they would only need reseating etc but if so, this points there being another reason why the power is not being made.

Fuelling was good on the rollers as I have got a new high pressure fuel pump with dedicated power and new aeroquip hose.

I have 2 graphs as I verified the 1st rolling road one with a Dyno Pack one (where they attach the machine directly to the hubs). The results were pretty much the same.

bud-weis

you'll need a ported head with at least new exhaust valves (not a good idea to use old valves for big power,standard size valves are fine) then some suitable cams for the spec.....your looking at a fair amount of cash really.

NMS do their own heads and they are very good,MADevelopments will also be able to spec one for you too,in fact a few tuners should be able to supply what you need for 500bhp...but it's gonna cost

rapidcossie

Damo...

alot of people think that its just a matter of bolting parts of an engine together and setting the boost for the power you want..


you now know its not that easy..

the person that is doing your mappin etc is more than capable of sorting a 500 bhp engine so i wold leave it to them.

either the head needs to come off or take the turbo and inlet off and see if the ports can be measured that way?


something needs to be done.

does the mapper have experience with the paticular rolling road?

FE

...interesting topic....curious to see if you get to the 500bhp mark !

DamoM

Thanks Martin. Appreciate the advice.

DamoM

Never really thought it was going to be that easy, and that is why I thought that the mapper should have explored the extent of the existing mods more thoroughly. I have just had my Audi RS4 remapped today to 520 bhp on std turbos (from 380 bhp) with no other mods than a better flowing exhaust. So it can be done with other cars.

Thing is with the cossie is that they become so far removed from std that to get the big power (and that is what we all crave... ) you need every i dotted and T crossed. I wasn't aware that the head needed such mods and it seems that my tuner has made an oversight as he is the expert!!!


The mapper doesn't know the dynos that I use and they map it on the road - just as I did today with my RS4! After my 8th time of going over 160 mph on a 60 mph dual carriageway I started to sweat a bit!

Thanks for your help Euan.

DamoM

I will keep you posted!

rapidcossie

stick with it and it will maul the RS4

jon@work

iTrader: (5)

Damo

tell me more about the RS4 mods - Milltek?, cats?, MRC map?, cost ?

(if you don't mind)

had mine for almost 4 years now - and it's still standard

DamoM

wrong forum really but quickly, miltek, full decat including pre cats, duh FMIC and yes, the famous MRC remap!! Do it, it it unbelievable getting all four wheels spinning in 2nd in the dry and having that power with full boost at 2500 rpm is the best of both worlds....

jon@work

iTrader: (5)

certainly is - but this site isn't as stuffy as rs246 so no-one will mind

thanks for the info

Fil

gotta get myself that famous MRC remap, sometime in feb

Dan

Thats the problem! Bloody good spec engine!

rapidcossie

why cant you get 500 bhp on standard head and cams?

Dan

Can a standard head not flow enough for that kind of power then mate?

rapidcossie

there is nothing stopping the head running 500 bhp...

you just need to run ALOT more boost than would be sensible..

Dan

Oh right!

So ideally a worked head is advisable then Euan?

Your's must be nicely over 500 isn't it, whats your head spec?

rapidcossie

my head has been flowed and ported and runs XYZ cams with standard valves.

you would always work the head as it increases the N/A sided of the engine.

lets you run less boost for more power, if you know what i mean.

but technically you can run any power you like thru the head as the air will always pass thru it, you just have to push it harder.

Dan

Ahh right, i'm with you mate, understand!

bud-weis

if you can get a standard head to flow 500bhp....i'll eat my favourite shoes

rapidcossie

why could you not get a standard head to flow 500 bhp?

does a brick wall form in the ports over a certain power?

bud-weis

well to make 500bhp the engine needs to consume more air,with standard cams the valves won't be open long enough for a start.

so the engine may only make 400bhp with 1.5bar on a T4 as it would with over 2bar on the same turbo,the extra boost/air flow is just backed up in the inlet because it can't be consumed, i reckon you can only force so much before you start to bottle neck

that's my theory anyway shame this isn't in GD for more discussion though

DazC

iTrader: (1)

I know of a 3 door that produced 490 at the wheels on a head with only mild work done to it plus a pair of BD14s.

bud-weis

still a long way from being standard

DamoM

Well in the end it turned out that the head on the car was indeed very well ported already! The cams were BD14s. Got the whole head rebuilt anyway with double valve springs.

The reason why the car wasn't producing the power was that the timing was out on the inlet cam. So much so that it was only the pockets machined into the pistons that saved impact. I took this matter up with the firm that did the work on my car and then mapped it and they basically told me that they never check cam timing and fully washed their hands of any responsibility. They were happy to take my money but not happy to accept that such a basic issue should have been checked.

I am unable to mention names in this forum but if anybody wants to know who (to avoid!) then PM me and I will let you know.

When it was rebuilt (by a chap called Piero Dicapite in Essex who I highly recommend) I took the car to Engine Advantages in Essex who after sorting out a couple of minor misfires, discovering that the pectel board that I had supplied the previous mappers was not there!, mapped the car succesfully to 485 bhp. I would recommend Engine Advantages too, they were superb and Piero even popped down to make sure everything went ok!

No quite the 500 but it feels pretty good anyway.

NUTTIN RILLA

Glad you got it sorted mate, more stress and money tho

cosy trav

iTrader: (1)

interesting this topic ,
im currently rebuilding my engine and having the head work done by cnc heads also known as ric wood racing in stockport manchester . not cheap though over a grand for the porting alone .

DamoM

couldn't recommend Piero DeCapite or Engine Advantages enough........they were superb.

Fil

DamoM


how the RS compare to the RS4