Remapping naturally aspirated engines
Discussion
Looking at getting my 745i remapped next week but a few have said no point on an NA engine, others have said definitely worth it...
Company in question are well regarded and claim 25-30bhp from a 333bhp 4.4L V8.
My thoughts are surely they can't claim those on websites when it doesn't make those gains, so surely it will make the gains?
Anyone done it on here? Interesting it varies from engine to engine, something highly tuned like the 4.0 V8 in the E92 M3 only gains around 10bhp which is a tiny percentage increase as opposed to almost 10% on mine.
Company in question are well regarded and claim 25-30bhp from a 333bhp 4.4L V8.
My thoughts are surely they can't claim those on websites when it doesn't make those gains, so surely it will make the gains?
Anyone done it on here? Interesting it varies from engine to engine, something highly tuned like the 4.0 V8 in the E92 M3 only gains around 10bhp which is a tiny percentage increase as opposed to almost 10% on mine.
Companies can claim what they like. Just look at all the "resistors" and "fuel savers" for sale, with their claims of miraculous results.
Turbo cars respond better to remapping, whereas NA cars only give relatively small gains. But in any case, the gain is pretty meaningless, after all you will only see that in top gear at high RPM, and how often do you find yourself doing that?
You should be looking at the overall improvement in the power and torque curves on the graph. A proper remap should always be done in conjunction with a rolling road session, and the map tweaked while the car is on the rollers.
Turbo cars respond better to remapping, whereas NA cars only give relatively small gains. But in any case, the gain is pretty meaningless, after all you will only see that in top gear at high RPM, and how often do you find yourself doing that?
You should be looking at the overall improvement in the power and torque curves on the graph. A proper remap should always be done in conjunction with a rolling road session, and the map tweaked while the car is on the rollers.
The only experience I have had of a remapped N/A was a mate's Alfa GTV 2.0 which I thought was a big improvement as it felt a bit lethargic and sluggish to reve beforehand but post-mapping, was far more eager to rev.
Having said that, it had had a service too so could be a combo of the two...
Having said that, it had had a service too so could be a combo of the two...
currybum said:
Appart from removing rev limiters what exactly are you expecting the map to change? Most engines have active knock control so there is nothing to gain there, you can't force more air in without changing hardware.
You can change the open loop AFR and ignition timing maps (and possibly valve timing maps if the engine has variable valve timing). It's entirely possible to make gains when remapping a normally aspirated engine, but they are usually fairly small compared to something with forced induction.Mr2Mike said:
You can change the open loop AFR and ignition timing maps (and possibly valve timing maps if the engine has variable valve timing). It's entirely possible to make gains when remapping a normally aspirated engine, but they are usually fairly small compared to something with forced induction.
^^^ This is entirely true and 10% is quite achievable especially if the engine is in a fairly lazy state of tune from the factory.Obviously higher specific power/litre cars are likely to gain less, cars such as an M3 for example.
Cars like a CV8 Monaro 5.7 V8 producing 'only' ~330bhp can be remapped to ~370/380bhp! Fact. Because its a lazy low specific power/litre engine with a lazy factory tune. 50bhp from a NA remap got to be worth having?!
lincsls2 said:
Mr2Mike said:
You can change the open loop AFR and ignition timing maps (and possibly valve timing maps if the engine has variable valve timing). It's entirely possible to make gains when remapping a normally aspirated engine, but they are usually fairly small compared to something with forced induction.
^^^ This is entirely true and 10% is quite achievable especially if the engine is in a fairly lazy state of tune from the factory.Obviously higher specific power/litre cars are likely to gain less, cars such as an M3 for example.
Cars like a CV8 Monaro 5.7 V8 producing 'only' ~330bhp can be remapped to ~370/380bhp! Fact. Because its a lazy low specific power/litre engine with a lazy factory tune. 50bhp from a NA remap got to be worth having?!
Obviously boosted cars can be turned up a lot further, but at what expense to their reliability? It's all well and good turning the wick up, but how long will it last at max boost?
well I know the chap doing it and so getting it relatively (ish) cheap and know a few guys who've had their cars remapped by him and say it's definitely worth it. 2 guys in particular who live close to me have had a C63 AMG tuned who said it was a massive difference and another with a BMW 330ci (E46) who said the power was certainly noticeable but he was getting a good 2mpg average more and it's stayed that way for thousands of miles and said he'd have no hesitation on recommending getting it done.
Going to get it done next week all being well
Going to get it done next week all being well
Ross, O/T I saw over on the barge thread you'd had problems with vibration at 65mph. I have a 55 plate 730d that has had this problem for a long time and I've had the suspension aligned and the wheels balanced but it's still there. If I might ask, what's the issue you have and have you solved it?
To be fair to turbo cars, I have remapped a few of mine in the past 3 turbo petrol and one turbo diesel car. Each of them made a minimum of ~20% more and none of them suffered in terms of reliability although I am quite sympathetic with my cars even though I can enjoy the extra performance.
bennyboydurham said:
Ross, O/T I saw over on the barge thread you'd had problems with vibration at 65mph. I have a 55 plate 730d that has had this problem for a long time and I've had the suspension aligned and the wheels balanced but it's still there. If I might ask, what's the issue you have and have you solved it?
you won't like me for this but yes, I've rectified the problem....NSF wheel was slightly buckled...swapped it for the spare wheel but also swapped the tyres (so the same tyres were on there) and had the wheels balanced and got 4 wheel alignment and the vibration has gone.
If you've not checked for buckled wheels then worth checking, I'd have thought it would be at all speeds but nope!
Worth checking CV joints too at the rear as I believe that can cause those issues but mine appeared ok
Yeah, poor old BMW, bloody hopeless they are. I mean, with access to the best engineers, techniques, multi million euro facilities and systems in the business and they completely fail to find an extra "25 bhp" just lurking there in their 745i engine calibration, but with a few hrs, and using just couple of grands worth of chassis dyno, a some guys in a shed can do it. They must be kicking themselves...............
Max_Torque said:
Yeah, poor old BMW, bloody hopeless they are. I mean, with access to the best engineers, techniques, multi million euro facilities and systems in the business and they completely fail to find an extra "25 bhp" just lurking there in their 745i engine calibration, but with a few hrs, and using just couple of grands worth of chassis dyno, a some guys in a shed can do it. They must be kicking themselves...............
The engineers are stifled by Euro emissions legislation, so they effectively detune most engines from the factory. Remappers have no such limits I don't think anyone has suggested that BMW are useless, far from it.
I think most manufacturers make compromises with their factory maps to account for emissions compliance etc etc. Also I believe they leave some slack in there engineering on purpose so they is room for improvement for the next models or facelift versions etc.
They also provide a hefty warranty and so factor in a margin for extra engine safety.
I think most manufacturers make compromises with their factory maps to account for emissions compliance etc etc. Also I believe they leave some slack in there engineering on purpose so they is room for improvement for the next models or facelift versions etc.
They also provide a hefty warranty and so factor in a margin for extra engine safety.
Max_Torque said:
Yeah, poor old BMW, bloody hopeless they are. I mean, with access to the best engineers, techniques, multi million euro facilities and systems in the business and they completely fail to find an extra "25 bhp" just lurking there in their 745i engine calibration, but with a few hrs, and using just couple of grands worth of chassis dyno, a some guys in a shed can do it. They must be kicking themselves...............
There are a whole number of reasons why BMW may have chosen the output of the engine that the car was released with. Emissions, different fuels, different environments etc.One of the top 2 remappers in Northern Ireland also claim +30hp after a remap. I would have no reason not to trust them.
currybum said:
No map I have ever seen on a gasoline NA engine has ever been stifled due to emissions, for these engines until you get particulate limits that drive you to a GPF most of the compliance is done in the after treatment. And even at stage 6.2 you'll probably be able to design around GPF's.
I'm interested to know what knobs in the map you suggest turning to get more power from a modern gasoline NA engine?
Its like a modern version of a k&n and a drilled airbox.I'm interested to know what knobs in the map you suggest turning to get more power from a modern gasoline NA engine?
Gassing Station | General Gassing | Top of Page | What's New | My Stuff