Discussion
I read with interest the news artical about the new triple bodied plenums from ACT, as I am looking to get a bit more go out of my standard 4.3 grif I was wondering if anyone had thoughts re. starting with the induction side of the engine or sort the heads out first. Also had a look at RPI Engineering website and I am interested on comments regarding their larger Air flow meter as the standard Rover one does seem restrictive.
Plan to do something once funds/wife allow!!!!
Thoughts Anyone????
Plan to do something once funds/wife allow!!!!
Thoughts Anyone????
quote:Done that, so getting back on topic, I am seriously considering an ACT carbon plenums and a Tornado chip as my next investment on the Griff, but now I am again confused
Do your brakes first.
! Previously we just had to choose between various sized throttle bodies and perhaps a Jag air-flow meter, then a few weeks ago Tim mentioned a twin plenum set-up he and Adam were working on now it's a Triple! Did the twin never make it into production and is the benefit of the tripple job really noticable or is it just for sprinters and real drivers 
My last estimation put the twin jobbie at around £1.7k plus all in with rolling road set up etc. questions question eh? Rich...quote:
quote:Done that, so getting back on topic, I am seriously considering an ACT carbon plenums and a Tornado chip as my next investment on the Griff, but now I am again confused
Do your brakes first.
Twin is the / will be the main road application one,
The triple is for monster engines !
Tim
quote:
anyone care to comment wether heads should be done before the induction.
Tim, I would be looking at the twin bodied plenum then, do you think that the bigger air flow meter as well will help?
If your talking about a 500 the heads, i would leave them, they are already big valve with huge porting, they lend themselves to a hotter cam, you only need to change heads if you want ultimate torque.
With air flow meters you will hear conflicting reports, engine buiders will say that upgrading makes no difference, in my experience and provided they are fitted in conjunction with Mark Adams remapping they do make a difference., they bolt directly onto the Carbon plenum.
Tim
Go for ported inlet manifold to match porting on heads (with suitably enlarged gasket) and new 46mm trumpet base. Fit 46mm trumpet base with matching belled trumpets, then fit an enlarged/ported plenum. Finally go for a Mark Adams ECU (or John Eales) and away you go. Power gains on bench dyno (i.e accurate) 25 BHP ish on a Griff 500. All the above are modified original components and give similar gains to the carbon fibre stuff only cheaper (~£400)
John Eales Developments or V8 Developments can source the necessary bits.
John Eales Developments or V8 Developments can source the necessary bits.
Just a small point here - ACT don't only do Carbon Fibre. They also do the Aluminium parts including John Eales' triple throttle plenum, large throttle single plenum, ported maninfolds, Carbon or Aluminium Trumpets, etc.
So ACT aren't pushing one particular technology, since everyone has different opinions! Whichever one you want, they can help....
Unless I am mistaken, the ACT triple throttle plenum uses trumpet bases supplied by John Eales and used on his own triple throttle plenums.
We are looking at the top league products here! Both of them work extremely well, and look fantastic. The Carbon plenums also have fabulous induction roar.
Very soon I hope to test the Aluminium and Carbon triple throttle plenums on my own 4.8 (when John has rebuilt it for me), against the standard plenum. Note this is a Lucas-GEMS managed engine, that already has modified inlet, heads, etc. If fellow PHs are interested then I will post the results.
So ACT aren't pushing one particular technology, since everyone has different opinions! Whichever one you want, they can help....
Unless I am mistaken, the ACT triple throttle plenum uses trumpet bases supplied by John Eales and used on his own triple throttle plenums.
We are looking at the top league products here! Both of them work extremely well, and look fantastic. The Carbon plenums also have fabulous induction roar.
Very soon I hope to test the Aluminium and Carbon triple throttle plenums on my own 4.8 (when John has rebuilt it for me), against the standard plenum. Note this is a Lucas-GEMS managed engine, that already has modified inlet, heads, etc. If fellow PHs are interested then I will post the results.
This is a note for Graham, but other people have expressed similar views. You may be ineterested in the dyno testing I have done, which will help you check your suppositions.
Logically, removing the airflow meter should help the power output, and that's what I thought too when I got started (about 14 years and 6,000 vehicles ago). However it makes very little difference to power except on very highly tuned motors, and actually damages mid-range torque to the tune of 10-15lb/ft.
The V8 does have plenty of surprises in terms of what you think it would like, and what it does like.
There is no better metering system than the hot wire or hot film airflow meter, as long as it is big enough (but not too big). This is because the engine's fuel requirements are really determined by the true mass of air that it is consuming at any given speed. Heated element meters score very heavily here since they compensate for temperature, barometric pressure, and humidity, all in one instrument!
If you use manifold pressure (MAP) sensing, then it is only usably accurate if you supplement it with barometric pressure and air temperature sensors.
There is one drawback here however. As the engine ages the vacuum will drop off, which the management system seed as increased load and then pushes up the fuelling. This will increase the wear rate and fuel consumption. The heated element metering system again scores because it sees the reduction in demand and responds accordingly.
Throttle angle metering is the least acuurate, but there is no choice where there is no plenum chamber. Again this needs air temperature and barometric pressure sensing to help it out. However it is never accurate since any given throttle opening and engine speed will cover a wide variety of loads. However the engine passes through them so quickly it won't be a major problem on a competition engine with throttle bodies!
Some people have replaced the management system because they want to be able to tweak it themselves. There are some very clever people out there, and this is a perfectly good reason. However please don't try to pass it off as an improvement. If you want an improvement then the Omex 3D mapped ignition system goes wonderfully well with the 14CUX and 4CU systems.
Actually the Omex is a very good system for the money, and there is a fuelling version available. It can be run off a hot-wire airflow meter or MAP sensor, and has air temperature sensing for ignition compensation.
Over the years I have programmed many of the aftermarket systems, and none of them come close to the sophistication of the standard system in terms of fuel management (apart from Motec). This is not really surprising looking at the budgets that go into them, and the legislation that the original manufacturers have to conform to. The only way to comply is by the most accurate metering.
My personal favourite system is the Lucas-GEMS system which is in a league of it's own, since it is effectivley self-programming. I have never seen anything that can hold a candle to it. However these systems are a closed book unless you have the programming information!
Looking at the direction of emmissions regulations, I would never recommend anyone to dump the main catalyst on a TVR (but do get rid of the pre cats!). This is a very short-sighted view. On the smaller engines the main cat doesn't make much difference to power anyway (3-5BHP).
Out of interest you can legally dump the cats on a Range Rover or Discovery because it is a 4x4 and weighs over 2040Kgs.
Didn't mean to ramble but I hope you found something interesting.
Logically, removing the airflow meter should help the power output, and that's what I thought too when I got started (about 14 years and 6,000 vehicles ago). However it makes very little difference to power except on very highly tuned motors, and actually damages mid-range torque to the tune of 10-15lb/ft.
The V8 does have plenty of surprises in terms of what you think it would like, and what it does like.
There is no better metering system than the hot wire or hot film airflow meter, as long as it is big enough (but not too big). This is because the engine's fuel requirements are really determined by the true mass of air that it is consuming at any given speed. Heated element meters score very heavily here since they compensate for temperature, barometric pressure, and humidity, all in one instrument!
If you use manifold pressure (MAP) sensing, then it is only usably accurate if you supplement it with barometric pressure and air temperature sensors.
There is one drawback here however. As the engine ages the vacuum will drop off, which the management system seed as increased load and then pushes up the fuelling. This will increase the wear rate and fuel consumption. The heated element metering system again scores because it sees the reduction in demand and responds accordingly.
Throttle angle metering is the least acuurate, but there is no choice where there is no plenum chamber. Again this needs air temperature and barometric pressure sensing to help it out. However it is never accurate since any given throttle opening and engine speed will cover a wide variety of loads. However the engine passes through them so quickly it won't be a major problem on a competition engine with throttle bodies!
Some people have replaced the management system because they want to be able to tweak it themselves. There are some very clever people out there, and this is a perfectly good reason. However please don't try to pass it off as an improvement. If you want an improvement then the Omex 3D mapped ignition system goes wonderfully well with the 14CUX and 4CU systems.
Actually the Omex is a very good system for the money, and there is a fuelling version available. It can be run off a hot-wire airflow meter or MAP sensor, and has air temperature sensing for ignition compensation.
Over the years I have programmed many of the aftermarket systems, and none of them come close to the sophistication of the standard system in terms of fuel management (apart from Motec). This is not really surprising looking at the budgets that go into them, and the legislation that the original manufacturers have to conform to. The only way to comply is by the most accurate metering.
My personal favourite system is the Lucas-GEMS system which is in a league of it's own, since it is effectivley self-programming. I have never seen anything that can hold a candle to it. However these systems are a closed book unless you have the programming information!
Looking at the direction of emmissions regulations, I would never recommend anyone to dump the main catalyst on a TVR (but do get rid of the pre cats!). This is a very short-sighted view. On the smaller engines the main cat doesn't make much difference to power anyway (3-5BHP).
Out of interest you can legally dump the cats on a Range Rover or Discovery because it is a 4x4 and weighs over 2040Kgs.
Didn't mean to ramble but I hope you found something interesting.
What sort of an increase in torque and power does removing the pre-cats give? Assume this is for all Griff 500s -mine is a 98. Is it an exhaust specialist job to replace with staight section pipes or you are saying take out the contents. Can you recommend who can do this cheaply (Fernie's maybe) or is it a DIY job if you have a 2 ton lift!
Chris
Chris
What sort of an increase in torque and power does removing the pre-cats give? Assume this is for all Griff 500s -mine is a 98. Is it an exhaust specialist job to replace with staight section pipes or you are saying take out the contents. Can you recommend who can do this cheaply (Fernie's maybe) or is it a DIY job if you have a 2 ton lift!
Chris
Chris
Hi Mark.
It was me who fitted graham's emerald system, had it mapped by darren at john Nobles just down the road in Chesterfield. But that was before I'd read your comments about air flow meters (to be fair Graham is looking at forced induction and the emerald was a good way to go for future playing and add-ons, I was also amazed how close I'd got the fuelling on road testing too although it's not a technique i wish to repeat too often!!!) but that torque issue removing the air flow meter is interesting, so should we be putting that back in and just leaving disconnected to bring the torque up even further? What's the effects taking place here that increase the torque - if there's torque to be had then we want it, but I'd also like to understand the principles which are affecting it too.
many thanks in advance ..
Joolz
It was me who fitted graham's emerald system, had it mapped by darren at john Nobles just down the road in Chesterfield. But that was before I'd read your comments about air flow meters (to be fair Graham is looking at forced induction and the emerald was a good way to go for future playing and add-ons, I was also amazed how close I'd got the fuelling on road testing too although it's not a technique i wish to repeat too often!!!) but that torque issue removing the air flow meter is interesting, so should we be putting that back in and just leaving disconnected to bring the torque up even further? What's the effects taking place here that increase the torque - if there's torque to be had then we want it, but I'd also like to understand the principles which are affecting it too.
many thanks in advance ..
Joolz
quote:
What sort of an increase in torque and power does removing the pre-cats give? Assume this is for all Griff 500s -mine is a 98. Is it an exhaust specialist job to replace with staight section pipes or you are saying take out the contents. Can you recommend who can do this cheaply (Fernie's maybe) or is it a DIY job if you have a 2 ton lift!
Chris
It doesn't. If you are going to upgrade the engine you have to think engine. You have to think what is stopping me getting more power out of the engine and address that.
The Heath guide to tuning the 500 is simple"
1. To get more bang you need to get more mixture in. This means bigger inlets, plenum, throttle etc. Potentially change cam. In extreme cases junk the airflow and go direct mapped but that is nutter mode 520 engine land.
2. Once you have got more mixture in, it helps to detonate it correctly. This means ECU chipping to complement point 1.
3. The exhaust is probably the leat critical of everything so do it last. Many of the engines I have modded run the standard exhausts, including the 520 BTW.
Focus on 1 and 2 (they are expensive enough) and then consider 3.
This is very simplistic as ECU functions can overlap but it gives you some idea of the thought processes involved.
Steve
>> Edited by shpub on Monday 30th September 09:25
>> Edited by shpub on Monday 30th September 09:54
Steve,
This was the first time I have heard about removing pre-cats hence the question. Mark had always told me that the later (after 95) Griff ECUS were very good, so not much he could improve upon ECU wise without other changes first. Confirm air mass flow is the critical factor,so agree with your other remarks.
Chris
This was the first time I have heard about removing pre-cats hence the question. Mark had always told me that the later (after 95) Griff ECUS were very good, so not much he could improve upon ECU wise without other changes first. Confirm air mass flow is the critical factor,so agree with your other remarks.
Chris
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