Megasquirt PnP (fuel only) - Up and Running
Discussion
Hi All, I finally got my PnP Megasquirt system mapped on Friday so thought I'd post my impressions so far
--Background--
decided to replace my original 4.0l engine with 76,000 miles on the clock last year with a new 5.0l motor form V8D, while the engine was out for a chassis rebuild.
Engine Spec:
• Stage 3 heads
• Stealth Cam
• ported inlet manifold
• Enlarged trumpet base and plenum
• ACT smooth bore induction kit.
• pre-cats removed
I initially bought a 2nd hand ECU with a Mark Adams chip which I was told by the seller was set up for a very similar engine spec. Unfortunately the fuel map proved to be way out, and the car shunted excessively round town and in traffic, so ended up running with the original 4.0l ECU which was a lot smoother. Dyno results for the two ECUs below.
5.0l ECU:
Max Power @ Wheels - 219.0 @ 5202 rpm
Max Power @ Flywheel - 245.1 @ 6030 rpm
Max Torque - 316.9 @ 3549 rpm
4.0l ECU:
Max Power @ Wheels - 240.3 @ 5921 rpm
Max Power @ Flywheel - 270.0 @ 5960 rpm
Max Torque - 282.3 @ 3584 rpm
Next plan was to get a new chip from Mark Adams. Mark is a really helpful and knowledgeable guy and offered to replace the chip with a base map for my engine pretty much for free as an interim measure before getting the car mapped, even though I bought the ECU second hand.
The main reason I didn't this route was because I live up in Aberdeen and the cost and logistics of getting the car to Mark for mapping were always going to be an issue, especially if more than one session was required.
In the end I decided to go with the fuel only PnP Megasquirt system for the following reasons:
• Mapping can be done locally
• Allows removal of Air flow Meter
• Easier to re-map if further mods carried out
• I'm an engineer
--Installation--
Straight forward and easy to change back to original if required
• Remove one of the resistors near the coil and install provided bridge connection
• Disconnect Fuel temp sensor and install MAT sensor cable
• Remove air flow meter and install supplied pipe with bung for MAT sensor
• Install ECU and Plug in Laptop.
Note, initially I didn't remove the air flow meter and just located the MAT sensor near the air filter as I only wanted to check if the car would start.
--Start-up--
This is where I had a few problems and it took a few attempts to get the car started with the base map. Once started it struggled to maintain a steady idle. I was very nervous about changing the MAP myself without a wideband sensor, so I bottled it and booked it in to get mapped on the dyno.
I was glad at this point that I had the fuel only system, as it took about 10 minutes to re-instate the original ECU and I was able to use the car until it was booked into the Mappers.
--Mapping--
Took it to the mappers on Friday. Was able to drive down with the original ECU and install the Megasquirt in about 15 minutes once I got there.
Only had about 2 hours and it took quite a while to get a steady idle, so didn't manage to get the fuelling exactly right, but I was happy with the results as a first pass.
After the mapping I had a few problems with the engine stuttering when pulling away, but after speaking with Shaun at V8D, we managed to smooth out fuelling in this area and now the car pulls away smoothly. Overall I feel like the car has been transformed and I’m very happy with the results.
I still think there's a bit more to come (maybe 310 bhp?) once I get the fuelling bang on. The Dyno operator also said power was down a bit due to the hot weather, so might get a bit more on a cooler day.
Also wondered what margin is normally added to the BHP at the wheels, 14% seems a bit conservative to me. I've seen 18 and even 20% used buy other people which would give an output of 312 bhp and 318 bhp respectively!
Further Work.
• Idle control still isn't quite right (need to use the throttle for a few seconds to maintain revs before it settles to a steady idle)
• Fine tuning of the Fuelling - I'm just about to order a Wideband sensor so that I can do any further mapping myself.
• Final power run once mapping is finished.
I'm also considering adding ignition mapping at a later date (wasted Spark), which I've been told will probably add about another 8 bhp. However the car is driving so well at the moment that can’t decide whether it worth it and once done its not easily reversible if there are any problems.
--Background--
decided to replace my original 4.0l engine with 76,000 miles on the clock last year with a new 5.0l motor form V8D, while the engine was out for a chassis rebuild.
Engine Spec:
• Stage 3 heads
• Stealth Cam
• ported inlet manifold
• Enlarged trumpet base and plenum
• ACT smooth bore induction kit.
• pre-cats removed
I initially bought a 2nd hand ECU with a Mark Adams chip which I was told by the seller was set up for a very similar engine spec. Unfortunately the fuel map proved to be way out, and the car shunted excessively round town and in traffic, so ended up running with the original 4.0l ECU which was a lot smoother. Dyno results for the two ECUs below.
5.0l ECU:
Max Power @ Wheels - 219.0 @ 5202 rpm
Max Power @ Flywheel - 245.1 @ 6030 rpm
Max Torque - 316.9 @ 3549 rpm
4.0l ECU:
Max Power @ Wheels - 240.3 @ 5921 rpm
Max Power @ Flywheel - 270.0 @ 5960 rpm
Max Torque - 282.3 @ 3584 rpm
Next plan was to get a new chip from Mark Adams. Mark is a really helpful and knowledgeable guy and offered to replace the chip with a base map for my engine pretty much for free as an interim measure before getting the car mapped, even though I bought the ECU second hand.
The main reason I didn't this route was because I live up in Aberdeen and the cost and logistics of getting the car to Mark for mapping were always going to be an issue, especially if more than one session was required.
In the end I decided to go with the fuel only PnP Megasquirt system for the following reasons:
• Mapping can be done locally
• Allows removal of Air flow Meter
• Easier to re-map if further mods carried out
• I'm an engineer
--Installation--
Straight forward and easy to change back to original if required
• Remove one of the resistors near the coil and install provided bridge connection
• Disconnect Fuel temp sensor and install MAT sensor cable
• Remove air flow meter and install supplied pipe with bung for MAT sensor
• Install ECU and Plug in Laptop.
Note, initially I didn't remove the air flow meter and just located the MAT sensor near the air filter as I only wanted to check if the car would start.
--Start-up--
This is where I had a few problems and it took a few attempts to get the car started with the base map. Once started it struggled to maintain a steady idle. I was very nervous about changing the MAP myself without a wideband sensor, so I bottled it and booked it in to get mapped on the dyno.
I was glad at this point that I had the fuel only system, as it took about 10 minutes to re-instate the original ECU and I was able to use the car until it was booked into the Mappers.
--Mapping--
Took it to the mappers on Friday. Was able to drive down with the original ECU and install the Megasquirt in about 15 minutes once I got there.
Only had about 2 hours and it took quite a while to get a steady idle, so didn't manage to get the fuelling exactly right, but I was happy with the results as a first pass.
After the mapping I had a few problems with the engine stuttering when pulling away, but after speaking with Shaun at V8D, we managed to smooth out fuelling in this area and now the car pulls away smoothly. Overall I feel like the car has been transformed and I’m very happy with the results.
I still think there's a bit more to come (maybe 310 bhp?) once I get the fuelling bang on. The Dyno operator also said power was down a bit due to the hot weather, so might get a bit more on a cooler day.
Also wondered what margin is normally added to the BHP at the wheels, 14% seems a bit conservative to me. I've seen 18 and even 20% used buy other people which would give an output of 312 bhp and 318 bhp respectively!
Further Work.
• Idle control still isn't quite right (need to use the throttle for a few seconds to maintain revs before it settles to a steady idle)
• Fine tuning of the Fuelling - I'm just about to order a Wideband sensor so that I can do any further mapping myself.
• Final power run once mapping is finished.
I'm also considering adding ignition mapping at a later date (wasted Spark), which I've been told will probably add about another 8 bhp. However the car is driving so well at the moment that can’t decide whether it worth it and once done its not easily reversible if there are any problems.
Sounds a great option.. must say this is the way I'd go as you can leave the car standard and swap back latter if required... Also the mapping to do yourself or at a local RR is a big plus... as you say, Mark is a great guy but very bussy... I've asked a couple of times now for mine re-doing but no reply so think this sounds the way to go.. 
angus99 said:
Also wondered what margin is normally added to the BHP at the wheels, 14% seems a bit conservative to me. I've seen 18 and even 20% used buy other people which would give an output of 312 bhp and 318 bhp respectively!
Nick, this baffles me. On my recent RR first run was 229.8 bhp at the wheels, 285.7 at the fly, which is close enough to 25% added to wheel figure to give fly figure. On the second run the car was extremely hot and power dropped to 227.8 at the wheels (2bhp less)and 270.6 at the fly (15.1bhp less). If the 25% was used again on the second run then the fly figure would have been 283.75, however it was given as 270.6, which is the figure you get if you add approximately 19%.So why 25% for transmission losses on the first run and 19% for transmission losses on the second run. (I didn't think to ask at the time as I was too chuffed with the first run results to look closely at the second)
Using the 25% figure on your car would give you 330 odd at the fly, which I have to say ties in more considering the mods you've had done. Alternatively, if they'd used 14% as the loss figure added on mine the fly figure on the first run would have been 262 bhp, bit of a long way off the 285 I've been convincing myself I've got. OK I know its all on paper but even so, given that we've all got the same drive trains (well almost) you might think there would be some kind of 'near standard' figure for transmission losses on a Chim/Griff...
All a bit of a nonsense in my humble opinion.
ETA: just read this, puts a different complexion on it.... http://www.pumaracing.co.uk/coastdwn.htm
Using the calculation suggested in the above link my second run fly bhp derived from wheel BHP is spot on, and the first run figure of 285 at the fly is fantasy...
Edited by Chilliman on Wednesday 8th June 15:38
Edited by Chilliman on Wednesday 8th June 15:49
Chilliman said:
Nick, this baffles me. On my recent RR first run was 229.8 bhp at the wheels, 285.7 at the fly, which is close enough to 25% added to wheel figure to give fly figure. On the second run the car was extremely hot and power dropped to 227.8 at the wheels (2bhp less)and 270.6 at the fly (15.1bhp less). If the 25% was used again on the second run then the fly figure would have been 283.75, however it was given as 270.6, which is the figure you get if you add approximately 19%.
So why 25% for transmission losses on the first run and 19% for transmission losses on the second run. (I didn't think to ask at the time as I was too chuffed with the first run results to look closely at the second)
Using the 25% figure on your car would give you 330 odd at the fly, which I have to say ties in more considering the mods you've had done. Alternatively, if they'd used 14% as the loss figure added on mine the fly figure on the first run would have been 262 bhp, bit of a long way off the 285 I've been convincing myself I've got. OK I know its all on paper but even so, given that we've all got the same drive trains (well almost) you might think there would be some kind of 'near standard' figure for transmission losses on a Chim/Griff...
All a bit of a nonsense in my humble opinion.
ETA: just read this, puts a different complexion on it.... http://www.pumaracing.co.uk/coastdwn.htm
Using the calculation suggested in the above link my second run fly bhp derived from wheel BHP is spot on, and the first run figure of 285 at the fly is fantasy...
So why 25% for transmission losses on the first run and 19% for transmission losses on the second run. (I didn't think to ask at the time as I was too chuffed with the first run results to look closely at the second)
Using the 25% figure on your car would give you 330 odd at the fly, which I have to say ties in more considering the mods you've had done. Alternatively, if they'd used 14% as the loss figure added on mine the fly figure on the first run would have been 262 bhp, bit of a long way off the 285 I've been convincing myself I've got. OK I know its all on paper but even so, given that we've all got the same drive trains (well almost) you might think there would be some kind of 'near standard' figure for transmission losses on a Chim/Griff...
All a bit of a nonsense in my humble opinion.
ETA: just read this, puts a different complexion on it.... http://www.pumaracing.co.uk/coastdwn.htm
Using the calculation suggested in the above link my second run fly bhp derived from wheel BHP is spot on, and the first run figure of 285 at the fly is fantasy...
Edited by Chilliman on Wednesday 8th June 15:38
Edited by Chilliman on Wednesday 8th June 15:49
once my PnP megasquirt was set up on the rollers it made 291 at the wheels which i was well happy with (thinking it would be about 350 ish) it was then converted to 318bhp at the flywheel 
.. ive given up trying to work it out - all i know is it goes like the clappers.
Seems a fairly accurate calc is peak bhp plus 10 bhp divided by 0.88. Hence my 238 at wheels became 270 at the fly, which seems the general agreed figure for a 'healthy' 500. Takes away all this percentage transmission loss variable depending on who you go to stuff.
I just want to know where all my torques are. 250 at 3000 rpm maxing at 280 at 4800 rpm. All the other 500's that are posted at around 270 peak bhp are showing 300 torques from less than 2000 rpm up... and maxing at 320
I'm assuming it's a fuelling issue
Still, MS2 going in back end of this month
I just want to know where all my torques are. 250 at 3000 rpm maxing at 280 at 4800 rpm. All the other 500's that are posted at around 270 peak bhp are showing 300 torques from less than 2000 rpm up... and maxing at 320
I'm assuming it's a fuelling issue
Still, MS2 going in back end of this month
Edited by Chilliman on Wednesday 8th June 19:18
Edited by Chilliman on Wednesday 8th June 19:24
Not sure I realy understand this rolling road stuff, at the wheels, at the flywheel, percentage numbers, car A produces this on that rolling road and car B produces that on another set of rollers.
Would be interesting to know if the OP had his pre megasquirt session on the same rollers as the post installation run, otherwise it means nothing.
The only usefull use for a rolling road is on the day tuning to get the optimum performance, eveything else IMHO is BS
Very interested in megasquirt, as I would like to get rid of the medeival way of timing the sparks and injection with a swish box of tricks. Then again my amp still uses valves and my record collection still sounds good on the turntable.
Andy
Would be interesting to know if the OP had his pre megasquirt session on the same rollers as the post installation run, otherwise it means nothing.
The only usefull use for a rolling road is on the day tuning to get the optimum performance, eveything else IMHO is BS
Very interested in megasquirt, as I would like to get rid of the medeival way of timing the sparks and injection with a swish box of tricks. Then again my amp still uses valves and my record collection still sounds good on the turntable.
Andy
Beastmaster, I'm having MS2 installed in a couple of weeks time, fuel & ignition. Standard 500, had it RR'd end of March, and am having no other mods done when the MS2 is installed. Was going to have 72mm plenum and 45mm trumpets put in at same time, but changed my mind as I want to see the difference the megasquirt only makes to the engine. Will be posting the results plus new RR after the install (same RR as used in March). I also have an MGBGT V8, 3.5 RV8, Lucas dizzy, one coil, twin SU's, and no modern electrickery, runs like a dream and a massive neck breaking 145 bhp at the fly
Edited by Chilliman on Wednesday 8th June 23:15
Thank for the feedback guys.
Just ordered a Techedge wideband system, so hopfully have this fitted in a week or so. Also had a look at the requirements for adding ignition mapping and I'm now thinking this might be a possibility later in the year.
On the power debate, the power runs on the original ECUs were done on the same dyno, which is the main thing for assessing any improvements. The reason for asking about the margins used in calculating flywheel power was just to get a comparison with other charts posted on here. Not sure why more peiople don't include the power at the wheels though. Incidentally using the equation posted above mine would be 312.5 bhp.
Just ordered a Techedge wideband system, so hopfully have this fitted in a week or so. Also had a look at the requirements for adding ignition mapping and I'm now thinking this might be a possibility later in the year.
On the power debate, the power runs on the original ECUs were done on the same dyno, which is the main thing for assessing any improvements. The reason for asking about the margins used in calculating flywheel power was just to get a comparison with other charts posted on here. Not sure why more peiople don't include the power at the wheels though. Incidentally using the equation posted above mine would be 312.5 bhp.
Just be aware that finding a RR willing to "learn" or tune your MS system may be problematic, so far I haven't found anyone in the south willing to do this. In fact worse as many are quite arrogant about it by saying it's inferior and don't want to accept that MS has moved on a huge amount since it was introduced as a low cost DIY kit.
Chilliman said:
I also have an MGBGT V8, 3.5 RV8, Lucas dizzy, one coil, twin SU's, and no modern electrickery, runs like a dream and a massive neck breaking 145 bhp at the fly
Chilliman - I understand what you are saying, but your MGBGT V8 was mighty in its day in comparison to other cars of the period, just as I see my Chimaera in 1994, the fact is that it's now 17 years old and it's not going to be head and shoulders above modern metal. Its testament to TVR that it takes something very special on two or four wheels, with a enthusiastic driver to look good nearly a decade later.Edited by Chilliman on Wednesday 8th June 23:15
I suppose what I was trying to say, my old record collection, with a quality turntable and valve amp, technology from a fast disappearing age adds something special to the music which can never be replicated in this digital age. It's the same with my TVR, I love it because it has soul, and would never compromise this for convenience
Just to mention, you do love your classic cars
Andy
Daz, sorry mate but that's incorrect, the reason the lump in the BGT was detuned was because of the gearbox not being up to more power and torque, it had nothing to do with the chassis or brakes. It's also why only the earliest V8's in '73 had synchro on third and fourth, as the 3rd gear synchro was consistently getting mullered by the 190 torques the engine put out. Mine's a '74 and has synchro on fourth only.
Did you see the etc part of my last post..meaning gearbox,Face it the car over all was not up to the job,They hate going round corners!I know the MGB`s like the back of my hand,owned a MGB Roadster for 9 years with suttle mods and a lovely 1860 Peter Burgess engine pulling 115bhp at the wheels ...wish i had kept that car..Also owned a Oxford blue MGRV8 nice car and sold it..No problem with the fuel cosumption on the 1860cc MGB 35mpg on a run..
http://www.carandclassic.co.uk/car/C104129
http://www.carandclassic.co.uk/car/C104129
SILICONEKID340HP said:
Did you see the etc part of my last post..meaning gearbox,Face it the car over all was not up to the job,They hate going round corners!I know the MGB`s like the back of my hand,owned a MGB Roadster for 9 years with suttle mods and a lovely 1860 Peter Burgess engine pulling 115bhp at the wheels ...wish i had kept that car..Also owned a Oxford blue MGRV8 nice car and sold it..No problem with the fuel cosumption on the 1860cc MGB 35mpg on a run..
http://www.carandclassic.co.uk/car/C104129
"face it, the car over all was not up to the job" Really ? What job might that be ?? http://www.carandclassic.co.uk/car/C104129
One question Daz; Have you owned a factory original BGT V8 ?
Oh, and I think your add says 109 bhp at the wheels, not 115. I've told you a million times not to exagerate
Apologies to the OP, we seem to be a bit off topic
Edited by Chilliman on Friday 10th June 19:24
Gassing Station | Chimaera | Top of Page | What's New | My Stuff