My Escort Cosworth, now on the road again ...
22-10-2008, 05:52 PM
#282
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it`s a mongoose system.. and it is high comp.. don't want to go into to much detail yet ( don`t want to start a low v high comp argument ! ), but after my test results, i could have gone higher..
22-10-2008, 06:23 PM
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22-10-2008, 06:28 PM
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Thanks mate...
Not had the dyno time yet, wanted to get a base line with pump fuel first.. but after the results with other cars i have used it on, would expect to see approx 40BHP ish + gain using E85 at the same boost level.. 600BHP may be possible, but wont know till i try,,
22-10-2008, 06:48 PM
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i think it may ( possibly ) be the highest power output achieved from a T38 so far ??
22-10-2008, 08:47 PM
#294
Sorry Dennis, but the figure of 550bhp is horse-shit 
. The TT T38 flows around 43-44lb of air, so it is a physical impossibility to get 550bhp out of it. I think you're adding too much transmission losses, as almost 130bhp loss through the transmission is too much - you only have to work out the heat that this equates to, and I know you're not stupid (well before you post I didn't think you were 
) .
With the hub dyno, I would say you are losing no more than 50-60bhp through the transmission, which is still truly awesome power for a T38 (and still the most power I have heard of out of one), but I think you are kidding yourself if you think it is 550bhp at 1.8 bar, as that is the kind of air flow you would expect from a GT35, and as good as your engine is, I don't think it is magical 
.
Beautifully prepared car and I hope to see you on track with my 500bhp / 2.2 bar T4 with 52lb air flow.
. The TT T38 flows around 43-44lb of air, so it is a physical impossibility to get 550bhp out of it. I think you're adding too much transmission losses, as almost 130bhp loss through the transmission is too much - you only have to work out the heat that this equates to, and I know you're not stupid (well before you post I didn't think you were ) .With the hub dyno, I would say you are losing no more than 50-60bhp through the transmission, which is still truly awesome power for a T38 (and still the most power I have heard of out of one), but I think you are kidding yourself if you think it is 550bhp at 1.8 bar, as that is the kind of air flow you would expect from a GT35, and as good as your engine is, I don't think it is magical
.Beautifully prepared car and I hope to see you on track with my 500bhp / 2.2 bar T4 with 52lb air flow
.
23-10-2008, 08:06 PM
#295
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[quote=Mike Rainbird;3678837]Sorry Dennis, but the figure of 550bhp is horse-shit .
Soz but made is laugh this lol dont hold back does he!
quality !
. Soz but made is laugh this lol dont hold back does he!
quality !
23-10-2008, 08:20 PM
#296
at only 1.8 bar boost she made 426.6 BHP and 340.3 LBF AT THE HUBS !!!
( about 550BHP at the fly depending on transmission loss )
although it wanted more boost, i am calling it a day on petrol, and moving on to E85 where it will be pushed to whatever it will make, but i want to get a very good transmission in first..
but for now.....
its an absolute animal !!!! it now spins all 4 toyo R888 in 2nd gear lol
..
( about 550BHP at the fly depending on transmission loss )
although it wanted more boost, i am calling it a day on petrol, and moving on to E85 where it will be pushed to whatever it will make, but i want to get a very good transmission in first..
but for now.....
its an absolute animal !!!! it now spins all 4 toyo R888 in 2nd gear lol
..
23-10-2008, 08:59 PM
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Hi mike, first off.. 50 / 60 hp loss would be about a 11% loss ??? i`m sure there more into the low 20`s but anyway, as i'm sure you are totally aware, the ONLY TRUE way to get a flywheel figure is on an engine dyno. And even then there are variables witch could effect the figure when fitted in its operating environment.
And for that reason, i only deal with hub figures, ( witch is why i quoted " about 550 at the fly depending on losses " to give an idea of approx fly numbers for those who don't)
i had no intentions of searching for numbers with my build, but as you kindly put " and as good as your engine is, I don't think it is magical" Neither do I...
it is what it is ...
( the turbo surge and relative drop in torque @ 4.5k is going to be dealt with as soon as i get some more dyno time )
Edited to say... Pressure is absolute !!
And for that reason, i only deal with hub figures, ( witch is why i quoted " about 550 at the fly depending on losses " to give an idea of approx fly numbers for those who don't)
i had no intentions of searching for numbers with my build, but as you kindly put " and as good as your engine is, I don't think it is magical" Neither do I...
it is what it is ...
( the turbo surge and relative drop in torque @ 4.5k is going to be dealt with as soon as i get some more dyno time )
Edited to say... Pressure is absolute !!
24-10-2008, 09:58 AM
#310
Dennis,
Hub dynos don't lose as much through the "wheels" as normal rolling roads and as you know, you can't even do a coast down on them either, so 130bhp transmission losses is nonsensical. Perhaps you should ask the manufacturers of this equipment what they think to your "guessed at" transmission losses on this car.
All you have to do is look at the compressor map for your turbo and you will know how silly your claims are
.
All that aside, I'm looking forward to seeing the resolution to the surge and power drop - this amount of power at the hubs is very good, but I would expect it to be 25-35bhp less on a set of DD rollers.
Hub dynos don't lose as much through the "wheels" as normal rolling roads and as you know, you can't even do a coast down on them either, so 130bhp transmission losses is nonsensical. Perhaps you should ask the manufacturers of this equipment what they think to your "guessed at" transmission losses on this car
.All you have to do is look at the compressor map for your turbo and you will know how silly your claims are
.All that aside, I'm looking forward to seeing the resolution to the surge and power drop - this amount of power at the hubs is very good, but I would expect it to be 25-35bhp less on a set of DD rollers
.
03-11-2008, 05:02 PM
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Dennis,
Hub dynos don't lose as much through the "wheels" as normal rolling roads and as you know, you can't even do a coast down on them either, so 130bhp transmission losses is nonsensical. Perhaps you should ask the manufacturers of this equipment what they think to your "guessed at" transmission losses on this car.
All you have to do is look at the compressor map for your turbo and you will know how silly your claims are.
All that aside, I'm looking forward to seeing the resolution to the surge and power drop - this amount of power at the hubs is very good, but I would expect it to be 25-35bhp less on a set of DD rollers.
Hub dynos don't lose as much through the "wheels" as normal rolling roads and as you know, you can't even do a coast down on them either, so 130bhp transmission losses is nonsensical. Perhaps you should ask the manufacturers of this equipment what they think to your "guessed at" transmission losses on this car
.All you have to do is look at the compressor map for your turbo and you will know how silly your claims are
.All that aside, I'm looking forward to seeing the resolution to the surge and power drop - this amount of power at the hubs is very good, but I would expect it to be 25-35bhp less on a set of DD rollers
.Exactly what laws of physics is this engine breaking?
Empirically supported facts only please, no opinions and do explain your workings.
PS, why on earth would you ever want to reference a straight "metal to metal" hub measurement back to the totally variable "pneumatic tyre to metal" rolling road measurement? makes no logical sense to me I'm afraid.
04-11-2008, 07:41 AM
#314
He is making more power than the physical air flow capabilities of the turbo - is that sufficient for you?
Every turbo is rated at a specific airflow, as a rough guide, if you multiply the airflow figures of the turbo by 10, you will get it's approximate physical horsepower limits. However, if you know what you're doing and build the engine VERY well with almost perfect VE, then you can add an additional 20-30bhp to that amount (but you're pushing the turbo to it's absolute limits).
Now given the fact that this engine is running 1.8 bar, all you have to do is draw a line on the graph (compressor map) from 1.8 bar and see what airflow this turbo achieves at this pressure. Suffice to say, I think you will find that it is considerably less than the approximate 55lb of air to achieve 550bhp (around 42lb to be precise). Therefore, if it is making 550bhp as claimed, then it is defying the laws of physics, or has a hidden NOS system .
It's not rocket science LOL!
Every turbo is rated at a specific airflow, as a rough guide, if you multiply the airflow figures of the turbo by 10, you will get it's approximate physical horsepower limits. However, if you know what you're doing and build the engine VERY well with almost perfect VE, then you can add an additional 20-30bhp to that amount (but you're pushing the turbo to it's absolute limits).
Now given the fact that this engine is running 1.8 bar, all you have to do is draw a line on the graph (compressor map) from 1.8 bar and see what airflow this turbo achieves at this pressure. Suffice to say, I think you will find that it is considerably less than the approximate 55lb of air to achieve 550bhp (around 42lb to be precise
). Therefore, if it is making 550bhp as claimed, then it is defying the laws of physics, or has a hidden NOS system .It's not rocket science LOL!
04-11-2008, 10:52 AM
#317
DEYTUKURJERBS
Easy to get away with in the Jap world, but generally Cossie owners seem to have more of a clue.
04-11-2008, 11:37 AM
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He is making more power than the physical air flow capabilities of the turbo - is that sufficient for you?
Every turbo is rated at a specific airflow, as a rough guide, if you multiply the airflow figures of the turbo by 10, you will get it's approximate physical horsepower limits. However, if you know what you're doing and build the engine VERY well with almost perfect VE, then you can add an additional 20-30bhp to that amount (but you're pushing the turbo to it's absolute limits).
Now given the fact that this engine is running 1.8 bar, all you have to do is draw a line on the graph (compressor map) from 1.8 bar and see what airflow this turbo achieves at this pressure. Suffice to say, I think you will find that it is considerably less than the approximate 55lb of air to achieve 550bhp (around 42lb to be precise). Therefore, if it is making 550bhp as claimed, then it is defying the laws of physics, or has a hidden NOS system .
It's not rocket science LOL!
Every turbo is rated at a specific airflow, as a rough guide, if you multiply the airflow figures of the turbo by 10, you will get it's approximate physical horsepower limits. However, if you know what you're doing and build the engine VERY well with almost perfect VE, then you can add an additional 20-30bhp to that amount (but you're pushing the turbo to it's absolute limits).
Now given the fact that this engine is running 1.8 bar, all you have to do is draw a line on the graph (compressor map) from 1.8 bar and see what airflow this turbo achieves at this pressure. Suffice to say, I think you will find that it is considerably less than the approximate 55lb of air to achieve 550bhp (around 42lb to be precise
). Therefore, if it is making 550bhp as claimed, then it is defying the laws of physics, or has a hidden NOS system .It's not rocket science LOL!
Who has given you these rules of thumb? I'm not saying that as rough rules they're miles out, but you seem to be letting your self get totally blinkered by them and that's not good.
Rainbird let me save you some time here, unless you can somehow "magically" calculate the the brake specific fuel consumption of Dennis's engine without access to the required data you simply don't know how much air is required to make the power.
You seem to have an overly simplistic understanding of what actually comes together to dictate an engines BMEP, the reality is that the rabbit hole goes very deep indeed especially when we're dealing with a turbocharged engine.
Look I'm not trying to beat you up here, you clearly understand a lot more than most people on this subject, but I honestly think you should reconsider your attacking position on this one in the face of the evidence because I can absolutely assure you that the Rototest dyno's are deadly accurate
04-11-2008, 02:08 PM
#319
Firstly 426.6bhp at the hub's is the number here, the attempt by Dennis to totally guess at a flywheel figure seems to have only muddied the waters so lets forget that pointless game and only argue about the hard numbers.
Who has given you these rules of thumb? I'm not saying that as rough rules they're miles out, but you seem to be letting your self get totally blinkered by them and that's not good.
Rainbird let me save you some time here, unless you can somehow "magically" calculate the the brake specific fuel consumption of Dennis's engine without access to the required data you simply don't know how much air is required to make the power.
You seem to have an overly simplistic understanding of what actually comes together to dictate an engines BMEP, the reality is that the rabbit hole goes very deep indeed especially when we're dealing with a turbocharged engine.
Look I'm not trying to beat you up here, you clearly understand a lot more than most people on this subject, but I honestly think you should reconsider your attacking position on this one in the face of the evidence because I can absolutely assure you that the Rototest dyno's are deadly accurate
Who has given you these rules of thumb? I'm not saying that as rough rules they're miles out, but you seem to be letting your self get totally blinkered by them and that's not good.
Rainbird let me save you some time here, unless you can somehow "magically" calculate the the brake specific fuel consumption of Dennis's engine without access to the required data you simply don't know how much air is required to make the power.
You seem to have an overly simplistic understanding of what actually comes together to dictate an engines BMEP, the reality is that the rabbit hole goes very deep indeed especially when we're dealing with a turbocharged engine.
Look I'm not trying to beat you up here, you clearly understand a lot more than most people on this subject, but I honestly think you should reconsider your attacking position on this one in the face of the evidence because I can absolutely assure you that the Rototest dyno's are deadly accurate
Before attacking me, might I suggest you learn to read, and then read the entire thread
. At NO POINT did I dispute the HUB figures, in fact I congratulated him on those figures, as they are very good 
. The point that I pulled him up upon, is the fact that Dennis then went on to extrapolate the hub figure as achieving 550bhp at the flywheel and it is ONLY the 550bhp figure that I am disputing . It doesn't matter HOW good his engine is, a T38 only pumps the amount of air it pumps. It is a physical limit and for you to dispute otherwise is showing your complete lack of understanding of turbos.As to the rule of thumb, this is given by the turbo manufacturers
. Look at the airflow figures quoted for the turbos and then the bhp range they attribute to that airflow . You will find that they are MUCH more pessimistc and if a turbo has 48lb air flow at it's peak pressure rating, they attribute it's power making ability as 480bhp at that figure or for 42lb air flow at 420bhp. However, from experience of the Cosworth engines, we know that with good head work and the right cams, the VE can be improved sufficiently that the turbo can make a bit more than this. So a T38 can make 465bhp (on it's knees) and maybe a bit more if the intake restrictions are removed (lets be generous and say 480bhp, as Dennis has a much more efficient intake than the standard item). I think you will agree that this is some way off the 550bhp (70bhp FFS ) that was being claimed (but 465-480bhp is about right for the losses I would expect from a Rototest dyno giving 426bhp at the hubs !). Perhaps if you don't want Dennis to bring your company into (further) disrepute, you should ensure he doesn't make such wild claims
.
Last edited by Mike Rainbird; 04-11-2008 at 02:33 PM.
04-11-2008, 04:11 PM
#320
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Are you seriously suggesting that I can't read?
Dennis didn't claim any such thing and you know it.
He simply said that the car made 426 @ the hubs and that if you apply such and such % loss then that equates to approx whatever at the flywheel. The only thing that was ever claimed was the hard figure of 426bhp at the hubs.
Just so we're clear I'm not attacking you, I just think that you should be fare in what you say.
You've come onto this thread and openly accused Dennis of being not only dis-honest but also an idiot. And for what, for developing his car using complex methods that you don't seem to have a grasp of and him being as good as to share the information with you guys. Most of the people replying to this thread seem genuinely chuffed with that, but not you.
You'll be amazed to hear that I have read this post entirely and thought that it was a great piece of reading for an enthusiast.
That is until you and a few others began to snipe at him, there's a difference between "discussing" a technical point (which is healthy)
and what some of you traders have been doing on here.
The bottom line is that if you're going to start spouting uninvited technical rhetoric all over somebody else's thread don't surprised if people like myself ask you to put up some fact, or shut up.
All I've seen from you so far is to quote other peoples rules of thumb mostly regarding estimated maximum rated outputs of turbo units based solely on compressor flow. Frankly if that's all you've got I would stop parading my ignorance.
PS, your numbers equate to around 11% transmission loss through a 1980's gearbox, 3 diff's, 2 props, 4 drive shafts and 4 wheel bearings. If it turns out that you are right then this is a truly awesome drive train...
Dennis didn't claim any such thing and you know it.
He simply said that the car made 426 @ the hubs and that if you apply such and such % loss then that equates to approx whatever at the flywheel. The only thing that was ever claimed was the hard figure of 426bhp at the hubs.
Just so we're clear I'm not attacking you, I just think that you should be fare in what you say.
You've come onto this thread and openly accused Dennis of being not only dis-honest but also an idiot. And for what, for developing his car using complex methods that you don't seem to have a grasp of and him being as good as to share the information with you guys. Most of the people replying to this thread seem genuinely chuffed with that, but not you.
You'll be amazed to hear that I have read this post entirely and thought that it was a great piece of reading for an enthusiast.
That is until you and a few others began to snipe at him, there's a difference between "discussing" a technical point (which is healthy)
and what some of you traders have been doing on here.
The bottom line is that if you're going to start spouting uninvited technical rhetoric all over somebody else's thread don't surprised if people like myself ask you to put up some fact, or shut up.
All I've seen from you so far is to quote other peoples rules of thumb mostly regarding estimated maximum rated outputs of turbo units based solely on compressor flow. Frankly if that's all you've got I would stop parading my ignorance.
PS, your numbers equate to around 11% transmission loss through a 1980's gearbox, 3 diff's, 2 props, 4 drive shafts and 4 wheel bearings. If it turns out that you are right then this is a truly awesome drive train...
Last edited by Jakyll; 04-11-2008 at 04:19 PM.