What sort of gain from a re-map with 4-2-1, filter, full de-cat, GMC cams?

16th October 2012, 16:36

Just wondering if anyone has any experience of having their car re-mapped with the above setup? What sort of power they were pushing pre-map and then afterwards? Did it transform the car?

Will be a re-map of the standard ecu (not aftermarket).

Also looking at getting a lightened flywheel put in when we do the gearbox swap (currently a vtr box with knackered syncho from 1st to 2nd gear attached to vts engine).. Will the flywheel make a big difference?

16th October 2012, 18:24

wouldnt have thought a remap from cams would massively transform the car maybe add 5-10bhp for the money your gonna spend i dont think you will see alot of bang for your buck.
when i looked into camming my vtr i got the cam and head and was expensive to fit around £500 mark to remap for the sake for a few extra bhp

16th October 2012, 18:55

Yeah been quoted £300+ vat today by automark up in Stokesley (north yorkshire).. Mine is a VTS as opposed to a VTR but on N/A cars I can't imagine a remap would be as effective as it has been on turbo cars I've owned in the past.

Having said that I get the impression that although it might not create much in the way of gains, getting the air filter, exhaust, manifold and cams all talking to each other properly would probably improve the delivery of the power which is already there, so I'm a bit mixed up about it all tbh.

I reckon my best bet for the time being is just to focus on getting the brakes sorted (266mm conversion and sort out the fuct bias compensator on the rear beam), sort out the rest of the weight loss (carpet, sound deadening, sunroof) and fit the oil cooler/vts gearbox I've just bought today.. then start faffing with re-maps.

16th October 2012, 20:32

A lot of people get roughly 145 ish bhp from the mods above, them mods above with weight saving and a lightened flywheel can upset a lot more expensive cars too

16th October 2012, 21:39

I felt with a map it improved running reliability, such as not stalling as much etc but definitely could feel a difference in power compared.

17th October 2012, 08:45

Quote:

Originally Posted by wheeler

Just wondering if anyone has any experience of having their car re-mapped with the above setup? What sort of power they were pushing pre-map and then afterwards? Did it transform the car?

Will be a re-map of the standard ecu (not aftermarket).

Also looking at getting a lightened flywheel put in when we do the gearbox swap (currently a vtr box with knackered syncho from 1st to 2nd gear attached to vts engine).. Will the flywheel make a big difference?

If you have a vtr g/box on a vts you will notice the difference when changing to correct g/box as it is 18% lower geared
remapping an n/a car will make very small differences if it is std as no car maker is going to restrict the bhp they can have on purpose
removing the cat will give a power lift of around 7 % ,presuming you are fitting an expansion box where the cat was -less if you do not fit a box where the cat was .
cams are always going to be the biggest factor in altering the bhp .
changing the manifold for a 4-2-1 of a cheap variety will probably give very little if any gain over the cast manifold is already 4-2-1 ,
my preference has always been to change to 4-1 with an expansion box where cat was-
as for remapping after fitting cams --this is where you decide is this the last mod or the beginning of other tuning - fitment of a 4.5 fpr and adjust ex cam to give best idle will give very much the same results as a remap and is cheaper
If you intend to go further with mods any more meaningfull engine mods would require fitment of a stand alone ecu anyway
--so you will decide if spending £300 now is good value ,when you will be binning that ecu later .
as for bhp --with a well matched exhaust manifold + system + cams you should expect around 150bhp @7100rpm with std single t/body from our cams
presuming all other ancillaries are good .eg hyraulic lifters,compression etc.

17th October 2012, 17:00

Quote:

Originally Posted by axsaxoman

as for remapping after fitting cams --this is where you decide is this the last mod or the beginning of other tuning - fitment of a 4.5 fpr and adjust ex cam to give best idle will give very much the same results as a remap and is cheaper

Are you trying to recommend people to increase the fuel pressure by 50% and not make calibration changes to suit?

18th October 2012, 09:39

only parts of the map that are open loop will result in higher fuel delivery as the closed loop parts will be corrected by the lambda probe .
If you expect to get a rise in bhp then you will need more fuel and the closed loop part will still be correct and the open loop will need more anyway as that part of the map is where you will be making the large increase in bhp .
the std ecu is quite capable of making up to 20% corrections in closed loop --this works I have done it many times and is an economic altenative to a remap and easily reversable
and if he decides to go t/bodies etc he would be very close to the max flow rate of std injectors without increasing fuel pressure ,so it is also cheapest way to make sure you have enough flow rate for the next step without buying injectors

18th October 2012, 11:30

closed loop - I fully agree that the EMS should take are of things using feedback from the lambda sensor.

have you tmeasured the WOT Lambda using this method of blinding increasing the fuel pressure 50% and hoping for the best to ensure that you are least in the right ball park?

18th October 2012, 11:58

Brilliant GMC thanks for the tip off buddy - gonna do some reading into FPR cost/fitting

19th October 2012, 08:30

Quote:

Originally Posted by wheeler

brilliant gmc thanks for the tip off buddy - gonna do some reading into fpr cost/fitting

4.5 fpr =£60 inc vat -replaces std unit -so 5mins to fit

19th October 2012, 09:29

Quote:

Originally Posted by yr51ocw

closed loop - I fully agree that the EMS should take are of things using feedback from the lambda sensor.

have you tmeasured the WOT Lambda using this method of blinding increasing the fuel pressure 50% and hoping for the best to ensure that you are least in the right ball park?

i HAVE DONE IT MANY TIMES and it works
can you tell me extra fuel do you think upping the fuel pressure by 1.5bar will give as a percentage increase ?
and how much extra fueling will you need if you raise the bhp by around 20-25%?
and more importantly how much over/under fuelling at WOT does the std ecu give ?
please also state correct fuelling in a lambda value for WOT at max power on these engines to get best bhp .
I think you should know these things before you start slagging my suggestions --as the inference is I do not know what i am doing

19th October 2012, 10:23

Standard ECU gives around 72% duty at top beans. On 3bar of Fuel pressure the injectors flow 225cc/min giving the 120-125bhp on the stock car.
Raising the fuel pressure to 4.5bar makes the injectors flow 275cc/min which at 72% duty is around 145bhp which given that the car will gain power from other breathing mods means that the fueling will be almost bang on.

Maths available on request but Google is your friend if you can really be bothered to argue

19th October 2012, 10:27

Quote:

Originally Posted by axsaxoman

i HAVE DONE IT MANY TIMES and it works
can you tell me extra fuel do you think upping the fuel pressure by 1.5bar will give as a percentage increase ?
and how much extra fueling will you need if you raise the bhp by around 20-25%?
and more importantly how much over/under fuelling at WOT does the std ecu give ?
please also state correct fuelling in a lambda value for WOT at max power on these engines to get best bhp .
I think you should know these things before you start slagging my suggestions --as the inference is I do not know what i am doing

Quote:

Originally Posted by luthor1

Standard ECU gives around 72% duty at top beans. On 3bar of Fuel pressure the injectors flow 225cc/min giving the 120-125bhp on the stock car.
Raising the fuel pressure to 4.5bar makes the injectors flow 275cc/min which at 72% duty is around 145bhp which given that the car will gain power from other breathing mods means that the fueling will be almost bang on.

Maths available on request but Google is your friend if you can really be bothered to argue

I just got deal with by the awesome police

cheers guys!

19th October 2012, 11:02

Interesting read!

So a breathed 16v won't be able to run to it's full potential with the stock fueling?

'removing cat gives roughly 7% power increase'

So 120+8.4 = 128.4bhp

So a 4-2-1 + center section + backbox + induction must be good for 5-10bhp?

so 128.4 + 5-10 = 133.4 - 138.4bhp?

But the stock injectors / pressure will only supply 120-125bhp?

Think upping the fuel pressure should be part of the 'breathing mods' then?

19th October 2012, 11:06

It depends if you are creating more "wheels power" by making a stronger fuel burn (using more fuel and air) or releasing existing power by removing a restriction (blocked exhaust).

One needs more fuel, the other doesn't - much like releasing the handbrake!

19th October 2012, 11:10

Ah I see!

But no matter what the mods the stock flow will only supply 120-125bhp?

So changing the exhaust / induction removes a restriction? Would this not give extra bhp? thus needed more fuel pressure?

19th October 2012, 11:13

the engine needs power to move the gas out the exhaust, so removing that restriction costs noise and releases power obviously there are more complicated aspects to it, but that's essentially part of it.

also the stock engine can run from 12.5:1 to 13.6:1 safely, so there is some headroom in there, ie it's a little rich as standard so *some* more air can go in which will lean the mixture down, but I mean leaning down from an already RICH position, not "going lean" meaning leaner than 14.7

19th October 2012, 11:17

Perfect explanation, Cheers!

So not needed unless changing cams, sounds right.

19th October 2012, 12:17

the injectors don't flow fuel at a steady rising rate with extra fuel pressure, add more and they get less efficient due to working outside their designed window.

19th October 2012, 13:44

Quote:

Originally Posted by axsaxoman

i HAVE DONE IT MANY TIMES and it works
can you tell me extra fuel do you think upping the fuel pressure by 1.5bar will give as a percentage increase ?
and how much extra fueling will you need if you raise the bhp by around 20-25%?
and more importantly how much over/under fuelling at WOT does the std ecu give ?
please also state correct fuelling in a lambda value for WOT at max power on these engines to get best bhp .
I think you should know these things before you start slagging my suggestions --as the inference is I do not know what i am doing

you still havent said if you measured exhaust lambda after doing your "mod"

Extra fuelling will depend on extra airflow, and optimum fuel required to prevent knock, if the engine is knock limited. So it is not a 20-25% increase in fuel required for a 20-25% increase in measured torque output at rated speed.

I am not inferring that you do not know what you are doing, im sure your fully aware. What I will state is the unscientific manor in which you openly admit you "tune" your engines is appaulling.

All N/A engines I have work on have given peak BHP at about 0.99-0.92 lambda, but each engine having their own "favourite" lambda (even engines of the same type, but different age etc...)

Unfortunatly with the engines I am working on, I have to stick to lambda 1 unless in component protection mode to ensure good fuel economy and to remain legal

19th October 2012, 15:15

I am not inferring that you do not know what you are doing, im sure your fully aware. What I will state is the unscientific manor in which you openly admit you "tune" your engines is appaulling.

firstly I did not say the fuelling would go up by 25%.
the effect on raising fuel pressure is much less than that -approx 10=-12% per bar of increase.
.
getting a car remapped with 100.000mile injectors and sensors is just as unscienific
they combustion charcteristics on this engineare are so good that when you have dialled in max bhp by timing you can advance it by long way before any sign of det --so its a very good designed engine to start with
I would always advise a stand alone or mapping for the perfect solution along with new injectors ,
but as most car makers do not give perfect mapping in the first place,they just make sure they are over rich at WOT --then my answer to the mans post is correct bearing in mind that I know this from experimentation and the fact that they are running 10+old cars are not looking for perfection ,but the best way /most economical way for the low level of mods suggested .

I cannot in truth justify telling someone to spend £300 mapping for a possible 4-5 bhp gain over the way i am suggesting to do it ,and as you have laready agreed when in closed loop +knock control the std ecu will sort it out .

me coming on here telling people they should always get their injectors matched +flow tested before doing any sort of tuning is not realistic ,and how many people fit new lifters when fitting new cams . --very few even though every cam maker say they should fit new lifters with new cams
same goes for uprated brg shells --never been asked for oversize ,so that means no one is regrinding the crank that is 10years old and has done maybe 100,000miles when building their mega engine
I can tell by the fact that 90% of pistons I sell are std size that most don,t even bother to rebore when doing even major engine conversions like turbo,s /supercharged or even very high revving n/a .
I have no problem working to the highest level ,but the customers cannot or do not want to go to those extremes .
so there are always compromises
so lets not kid ourselves that we are building F1 engines + ecu systems .
the question is always how cheap can i get "x" amount of bhp --