440 bhp rover v8 anyone??
Discussion
In response to dax, it depends how much you have lowered the compresion by? at 9.75 with 8psi you are going to be running some pretty high cylinder pressures there! with that you should be up around the 350 to 400 ftib mark so i would keep the revs well below 6000, maybe boosted or stevie turbo can help me on this one they seem to be the turbo boys
. v8 racing said:
......the injected one was a nightmare flooded on start up etc... i had to fit a switch so i could crank the engine and while cranking then fire the injectors! so absolutely no good as road going engines.
Ah AFAIK, Mr Adams chips do this, there is about a 1.5 sec delay added to allow the engine to get a bit of spped and get some oil flowing before releasing the fuel
. harry
v8 racing said:
Trying to answer as many questions as i can .
Sorry Rob i seem to have injected this topic with octane booster.
I have been doing trumpets for downdraft injection throttles recently, it seems to me that they are not necessarily better for a road car unless you keep the port a sensible size, 45mm with a resonable trumpet length, i know of 2 cars that have fitted 48mm or 50mm throttles and have gained nothing over basic injection.
Tim
daxtojeiro said:
what sort of rpm is safe for a fairly standard 3.5 Vitesse engine, which has been supercharged to around 8 psi?
Phil
Phil,
I'm sure your'e about to find out soon! - 5500rpm ish on std components is resonable i would think. Watch your oil pressure. (and your wide band, your laptop, oil temp, water temp - oh did i mention keep an eye on the road...)
Eliot.
Hi Rob,
interesting what you said about the injection overfuelling at cranking speeds. My motec had cranking enrichment decay settings. Basically as the engine turned over it added less fuel per revolution so it didn't flood. I really liked the Motec a lot, now I'm interested in the dta as it's got 8 coil drivers which suits the ls1 very nicely
As for revs, I always stayed pretty close to stock limits to keep the mechanical loads the same as stock. On 3.5-3.9's I'd rev to 7k on standatd internals for bursts up the gears. On the 5.0 I wouldn't go past 6k and that was again short bursts. Never needed to hold on as most cars dissappeared quick enough
. Traction off the line was always an issue though
interesting what you said about the injection overfuelling at cranking speeds. My motec had cranking enrichment decay settings. Basically as the engine turned over it added less fuel per revolution so it didn't flood. I really liked the Motec a lot, now I'm interested in the dta as it's got 8 coil drivers which suits the ls1 very nicely
As for revs, I always stayed pretty close to stock limits to keep the mechanical loads the same as stock. On 3.5-3.9's I'd rev to 7k on standatd internals for bursts up the gears. On the 5.0 I wouldn't go past 6k and that was again short bursts. Never needed to hold on as most cars dissappeared quick enough
. Traction off the line was always an issue thougheliot said:
Watch your oil pressure. (and your wide band, your laptop, oil temp, water temp - oh did i mention keep an eye on the road...)
Eliot.
But Ive only got two eyes!
I usually listen for detonation, watch the AFR and datalog at the same time, then go through the datalogs when I stop. 
Great thread by the way!
Phil
>> Edited by daxtojeiro on Thursday 8th April 10:41
The whole fuel pressure overfuelling is quite interesting. I have a fuel pressure gauge to monitor the pressure and it takes a few seconds for the twin pumps to stabilise the pressure. If I don't wait for this to happen, the engine is under fuelling until the pressure is reached. The DTA system has a cranking enrichment which means you can give an extra shot of fuel when cold starting and this seems to compensate. However it is very easy to flood the engine as a result and I reduced these settings by about 75% and just wait until it catches. When it did flood, it was change the plugs time.
With the 8 throttle body down draught injection I now have, the starting and low rev pulling is a lot smoother and a big improvement. However the costs are very high especially compared to carbs.
With the 8 throttle body down draught injection I now have, the starting and low rev pulling is a lot smoother and a big improvement. However the costs are very high especially compared to carbs.
Quite a few of my off-road clients have this system, including the yellow Bowler that was on Top Gear last year.
What is your intended application Mike?
The DTA system works only on throttle angle for metering. It is great for throttle body injection on a naturally aspirated (esecially competition) motor. It is an excellent choice for Steve's monster.
Where forced induction is concerned, I have some misgivings about the DTA, especially for turbo motors. Throttle angle is almost irrelevant on a turbo motor.
First you map the engine with no boost, making sure not to overspeed the turbos (which have no load). Then you connect them up, and re-run it. There is a linear table to fill in, of boost pressure fuelling enrichment and ignition retard.
The boost pressure table is purely that, so it has no relation to throttle angle or engine speed. In practice is works much better than you might expect, although there are some lumps and bumps in the fuelling and ignition.
By personal preference, I would prefer a MAP sensed system in these applications. My own recommendation would be MoTec, the new Omex 700, or one of the GEMS ECUs.
Some of the desert racers that have plenum chambers, are now converting from throttle angle DTA, to MoTec or Omex with an airflow meter. This copes much better with the massive temperature and altitude changes, and air filter clogging.
Additionally it gives better fuel economy too - important when your tank holds 250 Litres!
If you are retaining a plenum, then an airflow meter is the best way to go. Failing that MAP sensing will work, as long as you don't mind losing some mid-range torque for no power gain.
AFAIK the DTA traction control does not currently work on 4WD vehicles.
V8 Racing's twin AFM motor was run by a custom-built 4CU flapper ECU. For some reason, plenum equipped motors give their best with airflow meters - yes even flapper ones!
Don't ever believe that the 4CU flapper is second class. If it is built properly it will do most things for you. Not recommended for turbos though....
What is your intended application Mike?
The DTA system works only on throttle angle for metering. It is great for throttle body injection on a naturally aspirated (esecially competition) motor. It is an excellent choice for Steve's monster.
Where forced induction is concerned, I have some misgivings about the DTA, especially for turbo motors. Throttle angle is almost irrelevant on a turbo motor.
First you map the engine with no boost, making sure not to overspeed the turbos (which have no load). Then you connect them up, and re-run it. There is a linear table to fill in, of boost pressure fuelling enrichment and ignition retard.
The boost pressure table is purely that, so it has no relation to throttle angle or engine speed. In practice is works much better than you might expect, although there are some lumps and bumps in the fuelling and ignition.
By personal preference, I would prefer a MAP sensed system in these applications. My own recommendation would be MoTec, the new Omex 700, or one of the GEMS ECUs.
Some of the desert racers that have plenum chambers, are now converting from throttle angle DTA, to MoTec or Omex with an airflow meter. This copes much better with the massive temperature and altitude changes, and air filter clogging.
Additionally it gives better fuel economy too - important when your tank holds 250 Litres!
If you are retaining a plenum, then an airflow meter is the best way to go. Failing that MAP sensing will work, as long as you don't mind losing some mid-range torque for no power gain.
AFAIK the DTA traction control does not currently work on 4WD vehicles.
V8 Racing's twin AFM motor was run by a custom-built 4CU flapper ECU. For some reason, plenum equipped motors give their best with airflow meters - yes even flapper ones!
Don't ever believe that the 4CU flapper is second class. If it is built properly it will do most things for you. Not recommended for turbos though....
Hi,
may be of interest to you, I built and fitted a Megasquirt ECU to my supercharged RV8, MAP sensor or throttle position, depending on use. Its absolutely excellent and costs about £100 to build. Add in a WideBand Lambda sensor for around £150 and you have a really good setup for £250!! Completely mappable, etc, etc. You have to build it yourself, but its only a case of doing some soldering, if you can build an engine, then this wont be beyond you in any way!
http://autos.groups.yahoo.com/group/megasquirt/
www.bgsoflex.com/megasquirt.html
Have a look at least, more info on my website if you need it, under "replaceing ECU"
Phil
http:/www.replica-cobra.co.uk
may be of interest to you, I built and fitted a Megasquirt ECU to my supercharged RV8, MAP sensor or throttle position, depending on use. Its absolutely excellent and costs about £100 to build. Add in a WideBand Lambda sensor for around £150 and you have a really good setup for £250!! Completely mappable, etc, etc. You have to build it yourself, but its only a case of doing some soldering, if you can build an engine, then this wont be beyond you in any way!
http://autos.groups.yahoo.com/group/megasquirt/
www.bgsoflex.com/megasquirt.html
Have a look at least, more info on my website if you need it, under "replaceing ECU"
Phil
http:/www.replica-cobra.co.uk
Hi Phil
Actually I have visited your site in the past, and the MegaSquirt one as well. One should always do one's homework, don't you think?
You are obviously a clever guy, and your site looks very good with stacks of info. The install looks great, and that may be the shiniest plenum I have ever seen!
Another smart chap is Lee Progl who has done a similar thing to a Lightweight Land Rover. It may be worth you taking a look at his site on:
www.progl.com
Generally the MegaSquirt system covers a totally different kind of customer to the ones I see. Most people just don't want to get involved, not because they aren't capable of it. Therefore they use what is there or buy a ready-made one.
However there is another more ominous issue, which has major implications for people in the trade supplying the systems to real customers. If you sell an aftermarket ECU, there is a lot of recent legislation that affects it. In fact it is or soon will be illegal to fit an uapproved system, and will not be insurable.
Obviously as a business I could not sell an unapproved system, however good it may be. This is another sad stifling product of our litigious blame culture world...
I'm a bit hazy about the exact details, but suffice it to say that MoTec, Omex and GEMS systems have all forked out the required dosh for the necessary approvals and manufacturing standards.
However I can't see it having a major effect on self-built vehicles. I shall do my homework and report back, because I absolutely should know the details.
On another note, I hope you won't be offended if I offer you a couple of bits of advice, based on stuff I have learned over a lot of motors. These points are all a pain to find, and will waste your time.
Firstly it is a mistake to lock up the distributor advance mechanism with mapped ignition. The mechanical advance helps to put the rotor arm in the right position to exploit higher advances at higher speeds. It is a particular problem with the Rover rotor arm, because the tip of it is so short. Higher loads at higher speeds can generate cross-firing between adjacent contact pegs.
If you look at cars with distributors specifically for mapped ignition, you will find that the trailing edge of the rotor arm is very long.
A good starting point for the MSD retard rate is 0.5 Degrees per pound of boost.
You have not said what fuel pressure regulator you have used, but you would be better off with a standard one or Omex Billet 3.0 Bar Linear item. I have had trouble with the FSE items with forced induction. They start off OK, but eventually the fuel pressure does NOT rise on boost anymore. I think the diaphragms go saggy.
It is best to keep the fuel pressure as low as you can get away with, since the flow rate of the fuel pump drops off dramatically with pressure. Since you are using only modest boost, I don't think this will be a problem.
Lastly, 36 Degrees of advance rang some major alarm bells for me! Almost all V8 lumps will usually pink at this kind of advance, even naturally aspirated. The only reason it may not be showing up is if the mixture is grossly rich. I would back it off to 28 Degrees, and get it on the rollers as fast as possible.
Please let us know how you get on!
>> edited for typos
>> Edited by Mark Adams on Saturday 10th April 20:29
Actually I have visited your site in the past, and the MegaSquirt one as well. One should always do one's homework, don't you think?
You are obviously a clever guy, and your site looks very good with stacks of info. The install looks great, and that may be the shiniest plenum I have ever seen!
Another smart chap is Lee Progl who has done a similar thing to a Lightweight Land Rover. It may be worth you taking a look at his site on:
www.progl.com
Generally the MegaSquirt system covers a totally different kind of customer to the ones I see. Most people just don't want to get involved, not because they aren't capable of it. Therefore they use what is there or buy a ready-made one.
However there is another more ominous issue, which has major implications for people in the trade supplying the systems to real customers. If you sell an aftermarket ECU, there is a lot of recent legislation that affects it. In fact it is or soon will be illegal to fit an uapproved system, and will not be insurable.
Obviously as a business I could not sell an unapproved system, however good it may be. This is another sad stifling product of our litigious blame culture world...
I'm a bit hazy about the exact details, but suffice it to say that MoTec, Omex and GEMS systems have all forked out the required dosh for the necessary approvals and manufacturing standards.
However I can't see it having a major effect on self-built vehicles. I shall do my homework and report back, because I absolutely should know the details.
On another note, I hope you won't be offended if I offer you a couple of bits of advice, based on stuff I have learned over a lot of motors. These points are all a pain to find, and will waste your time.
Firstly it is a mistake to lock up the distributor advance mechanism with mapped ignition. The mechanical advance helps to put the rotor arm in the right position to exploit higher advances at higher speeds. It is a particular problem with the Rover rotor arm, because the tip of it is so short. Higher loads at higher speeds can generate cross-firing between adjacent contact pegs.
If you look at cars with distributors specifically for mapped ignition, you will find that the trailing edge of the rotor arm is very long.
A good starting point for the MSD retard rate is 0.5 Degrees per pound of boost.
You have not said what fuel pressure regulator you have used, but you would be better off with a standard one or Omex Billet 3.0 Bar Linear item. I have had trouble with the FSE items with forced induction. They start off OK, but eventually the fuel pressure does NOT rise on boost anymore. I think the diaphragms go saggy.
It is best to keep the fuel pressure as low as you can get away with, since the flow rate of the fuel pump drops off dramatically with pressure. Since you are using only modest boost, I don't think this will be a problem.
Lastly, 36 Degrees of advance rang some major alarm bells for me! Almost all V8 lumps will usually pink at this kind of advance, even naturally aspirated. The only reason it may not be showing up is if the mixture is grossly rich. I would back it off to 28 Degrees, and get it on the rollers as fast as possible.
Please let us know how you get on!
>> edited for typos
>> Edited by Mark Adams on Saturday 10th April 20:29
Hello Mark,
It's a blown LS1. I used the motec with it's map input on my Rovers but when I went the ls1 route I realised the Motec couldn't handle 8 coils. I was offerred good money for it so let it go. I did like it's versatility but it was an older model circa 1994. I used Map as the primary input and throttle angle as the secondary input. As far as I am aware the DTA does have a MAP input, if not I won't be buying it! The traction control also appeals to me.
Mike.
It's a blown LS1. I used the motec with it's map input on my Rovers but when I went the ls1 route I realised the Motec couldn't handle 8 coils. I was offerred good money for it so let it go. I did like it's versatility but it was an older model circa 1994. I used Map as the primary input and throttle angle as the secondary input. As far as I am aware the DTA does have a MAP input, if not I won't be buying it! The traction control also appeals to me.
Mike.
Hi Mike
That sure is a lot of coils! To date, DTA Primary metering is always throttle angle. It only uses MAP as a secondary correction.
There is another challenge with throttle angle metering, in that you cannot really do idle speed control without Lambda sensors. If Primary metering is throttle angle, then opening a bypass weakens the mixture thus making it more likely to stall. Lambda sensors can sometimes correct for this, if the idle bypass is quite slow.
I do believe there is a GEMS unit that will drive this configuration, so I can check up if you like.
How many injectors do you want, and can you go semi-sequential? Otherwise ther may be a limitation on the number of outputs available.
Sequential is a bit of a pain in many cases, since most aftermarket ECUs require only one tooth on the sync reference sensor. Hope this helps!
That sure is a lot of coils! To date, DTA Primary metering is always throttle angle. It only uses MAP as a secondary correction.
There is another challenge with throttle angle metering, in that you cannot really do idle speed control without Lambda sensors. If Primary metering is throttle angle, then opening a bypass weakens the mixture thus making it more likely to stall. Lambda sensors can sometimes correct for this, if the idle bypass is quite slow.
I do believe there is a GEMS unit that will drive this configuration, so I can check up if you like.
How many injectors do you want, and can you go semi-sequential? Otherwise ther may be a limitation on the number of outputs available.
Sequential is a bit of a pain in many cases, since most aftermarket ECUs require only one tooth on the sync reference sensor. Hope this helps!
Thanks for the offer Mark. Sure, please check for me. I want to use batch fire and am not interested in sequential. This way I think I can keep the stock injectors and fire them twice. There are 8 injectors and it's coil per plug. Quite tidy really. I have a 36-1 internal crank trigger wheel and there is a cam sensor as well. Thing is, I really need something I can tweak myself as I'm always 'fiddling' with something. Can the GEMS unit be mapped with a lap top? I intend to use wide band lamda's. See here:
www.techedge.com.au/vehicle/wbo2/default.htm
Any help is always appreciated. Oh, I got your message earlier.
Mike
www.techedge.com.au/vehicle/wbo2/default.htm
Any help is always appreciated. Oh, I got your message earlier.
Mike
Hi Mark,
sorry, had no idea you were in business selling ECU's interesting about the laws though.
Thanks for the detailed reply and for the points, I was also concerned by the rotor arm not being able to swing with the engine speed, but I set it so it sat in the middle of the contact at around 18degrees, half my max advance, and it seems to be fine.
I also agree about the max advance, but this is how I worked it out, my dizzy was capable of a total of 28 degrees mechanical advance plus the static of 8 degrees gave it 36 max. Not trusting that alone, I searched the internet and found 2 sites which agreed with my findings, so thats were the figure came from, but I do agree it sounds like alot. I cant hear any detonation, and it's running at 12.5 AFR in boost and 14.7 AFR cruising, so not rich really.
Sorry for taking up space on this thread, its very good.
Phil
sorry, had no idea you were in business selling ECU's interesting about the laws though.
Thanks for the detailed reply and for the points, I was also concerned by the rotor arm not being able to swing with the engine speed, but I set it so it sat in the middle of the contact at around 18degrees, half my max advance, and it seems to be fine.
I also agree about the max advance, but this is how I worked it out, my dizzy was capable of a total of 28 degrees mechanical advance plus the static of 8 degrees gave it 36 max. Not trusting that alone, I searched the internet and found 2 sites which agreed with my findings, so thats were the figure came from, but I do agree it sounds like alot. I cant hear any detonation, and it's running at 12.5 AFR in boost and 14.7 AFR cruising, so not rich really.
Sorry for taking up space on this thread, its very good.
Phil
Boosted LS1 said:
shpub,
What was your overall opinion of the dta? Was it an m8pro? I'm wondering about one of these for myself. I think Stevie likes his unit.
Mike.
It's the ECU8 the M8Pro predecessor. I don't do the mapping - John Eales does that for me but it has been very reliable and the diagnostics is good. Very useful for identifying other problems with the installation.
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