A simple engine question.....
10-04-2006, 06:16 PM
#122
Fair enough MarkK, i agree with you there.
If i was building the engine im building currently for a customer, i would have a lower CR to encourage it to last, but as it is i will understand the level of mechanical sympathy i give it can have a very pronounced effect on its lifespan due to the PCP's and EGT's involved.
Its different building things for yourself to for other people.
If i was building the engine im building currently for a customer, i would have a lower CR to encourage it to last, but as it is i will understand the level of mechanical sympathy i give it can have a very pronounced effect on its lifespan due to the PCP's and EGT's involved.
Its different building things for yourself to for other people.
10-04-2006, 06:18 PM
#123
Originally Posted by MarkTurbo
Glad i sat down and read all this topic 
It makes excellent reading material guys 
Especially as i've raised the compression on my car
It makes excellent reading material guys Especially as i've raised the compression on my car
10-04-2006, 06:18 PM
#124
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89XR2 it'ds completly on the side of this discussion and of course you are right, but un-resricted engine was considered only as an example or completly different aproach and to show why restricted engines are different form big power road engines.
10-04-2006, 07:54 PM
#125
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Originally Posted by chip-3door
Originally Posted by MarkTurbo
Glad i sat down and read all this topic It makes excellent reading material guys
Especially as i've raised the compression on my car
It makes excellent reading material guys Especially as i've raised the compression on my car
Fook the gearbox (which it probably would )
10-04-2006, 08:09 PM
#126
Originally Posted by MarkTurbo
Originally Posted by chip-3door
Originally Posted by MarkTurbo
Glad i sat down and read all this topic It makes excellent reading material guys
Especially as i've raised the compression on my car
It makes excellent reading material guys Especially as i've raised the compression on my car
Fook the gearbox (which it probably would )
11-04-2006, 09:05 AM
#127
Mark,
I've tried almost every possible configuration of compression, so I am talking from experience and am not blinkered at all. I totally understand what each change means as an on cost in other changes required. EVERYTHING brings with it compromises, but in my experience high compression brings the worse type of compromise (on pump fuel) and that is retarded ignition (for equal boost pressure on a lower compression engine).
Let's use Phil's engine as an example, a relatively low 7.9:1, but to stop it from detting at 32psi, he is forced to have MASSIVELY retarded ignition (Phil's engine is running single figures at high rpm
). This puts HUGE amounts of heat in an engine, and on a road car is totally unacceptable (I shouldn't think it is too sharp on a race engine either ). His engine shouldn't go bang, but his exhaust manifold and turbo might fall off wth the high EGTs / heat . Now he has quoted another tuner's car running even HIGHER compression, yet can't seem to grasp what that must mean to the ignition curve or boost curve - either or both of them must be severly retarded at the top end to give acceptable PCPs to stop the engine from going bang.
Ideally, you want something like Saab developed, which was a variable compression engine - now THAT was.
I've tried almost every possible configuration of compression, so I am talking from experience and am not blinkered at all. I totally understand what each change means as an on cost in other changes required. EVERYTHING brings with it compromises, but in my experience high compression brings the worse type of compromise (on pump fuel) and that is retarded ignition (for equal boost pressure on a lower compression engine).
Let's use Phil's engine as an example, a relatively low 7.9:1, but to stop it from detting at 32psi, he is forced to have MASSIVELY retarded ignition (Phil's engine is running single figures at high rpm
). This puts HUGE amounts of heat in an engine, and on a road car is totally unacceptable (I shouldn't think it is too sharp on a race engine either ). His engine shouldn't go bang, but his exhaust manifold and turbo might fall off wth the high EGTs / heat . Now he has quoted another tuner's car running even HIGHER compression, yet can't seem to grasp what that must mean to the ignition curve or boost curve - either or both of them must be severly retarded at the top end to give acceptable PCPs to stop the engine from going bang.Ideally, you want something like Saab developed, which was a variable compression engine - now THAT was
.
11-04-2006, 09:09 AM
#128
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Originally Posted by Mike Rainbird
Mark,
I've tried almost every possible configuration of compression, so I am talking from experience and am not blinkered at all. I totally understand what each change means as an on cost in other changes required. EVERYTHING brings with it compromises, but in my experience high compression brings the worse type of compromise (on pump fuel) and that is retarded ignition (for equal boost pressure on a lower compression engine).
Let's use Phil's engine as an example, a relatively low 7.9:1, but to stop it from detting at 32psi, he is forced to have MASSIVELY retarded ignition (Phil's engine is running single figures at high rpm ). This puts HUGE amounts of heat in an engine, and on a road car is totally unacceptable (I shouldn't think it is too sharp on a race engine either ). His engine shouldn't go bang, but his exhaust manifold and turbo might fall off wth the high EGTs / heat . Now he has quoted another tuner's car running even HIGHER compression, yet can't seem to grasp what that must mean to the ignition curve or boost curve - either or both of them must be severly retarded at the top end to give acceptable PCPs to stop the engine from going bang.
I've tried almost every possible configuration of compression, so I am talking from experience and am not blinkered at all. I totally understand what each change means as an on cost in other changes required. EVERYTHING brings with it compromises, but in my experience high compression brings the worse type of compromise (on pump fuel) and that is retarded ignition (for equal boost pressure on a lower compression engine).
Let's use Phil's engine as an example, a relatively low 7.9:1, but to stop it from detting at 32psi, he is forced to have MASSIVELY retarded ignition (Phil's engine is running single figures at high rpm
). This puts HUGE amounts of heat in an engine, and on a road car is totally unacceptable (I shouldn't think it is too sharp on a race engine either ). His engine shouldn't go bang, but his exhaust manifold and turbo might fall off wth the high EGTs / heat . Now he has quoted another tuner's car running even HIGHER compression, yet can't seem to grasp what that must mean to the ignition curve or boost curve - either or both of them must be severly retarded at the top end to give acceptable PCPs to stop the engine from going bang.
11-04-2006, 10:14 AM
#130
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Originally Posted by TM
................how do you know what Retard Phil is running
11-04-2006, 12:54 PM
#132
Mike it starts in singles but as the revs rise so does the advance to double figures 
...so not single all the way!
As i said you need to drive mine and compare it to your lo comp engine...you will find mine massively more a ROAD car engine than yours was!
Remember i had a lo comp version too.
...so not single all the way!As i said you need to drive mine and compare it to your lo comp engine...you will find mine massively more a ROAD car engine than yours was!
Remember i had a lo comp version too.
11-04-2006, 01:12 PM
#133
Originally Posted by Bosch-Man
Mike it starts in singles but as the revs rise so does the advance to double figures ...so not single all the way!
As i said you need to drive mine and compare it to your lo comp engine...you will find mine massively more a ROAD car engine than yours was!
Remember i had a lo comp version too.
...so not single all the way!As i said you need to drive mine and compare it to your lo comp engine...you will find mine massively more a ROAD car engine than yours was!
Remember i had a lo comp version too.
. You hurry up and get your arse up to Norfolk, and you'll be eating your words about my engine compared to yours .
11-04-2006, 05:27 PM
#134
Originally Posted by Mike Rainbird
Mark,
I've tried almost every possible configuration of compression, so I am talking from experience and am not blinkered at all. I totally understand what each change means as an on cost in other changes required. EVERYTHING brings with it compromises, but in my experience high compression brings the worse type of compromise (on pump fuel) and that is retarded ignition (for equal boost pressure on a lower compression engine).
Let's use Phil's engine as an example, a relatively low 7.9:1, but to stop it from detting at 32psi, he is forced to have MASSIVELY retarded ignition (Phil's engine is running single figures at high rpm ). This puts HUGE amounts of heat in an engine, and on a road car is totally unacceptable (I shouldn't think it is too sharp on a race engine either ). His engine shouldn't go bang, but his exhaust manifold and turbo might fall off wth the high EGTs / heat . Now he has quoted another tuner's car running even HIGHER compression, yet can't seem to grasp what that must mean to the ignition curve or boost curve - either or both of them must be severly retarded at the top end to give acceptable PCPs to stop the engine from going bang.
Ideally, you want something like Saab developed, which was a variable compression engine - now THAT was.
I've tried almost every possible configuration of compression, so I am talking from experience and am not blinkered at all. I totally understand what each change means as an on cost in other changes required. EVERYTHING brings with it compromises, but in my experience high compression brings the worse type of compromise (on pump fuel) and that is retarded ignition (for equal boost pressure on a lower compression engine).
Let's use Phil's engine as an example, a relatively low 7.9:1, but to stop it from detting at 32psi, he is forced to have MASSIVELY retarded ignition (Phil's engine is running single figures at high rpm
). This puts HUGE amounts of heat in an engine, and on a road car is totally unacceptable (I shouldn't think it is too sharp on a race engine either ). His engine shouldn't go bang, but his exhaust manifold and turbo might fall off wth the high EGTs / heat . Now he has quoted another tuner's car running even HIGHER compression, yet can't seem to grasp what that must mean to the ignition curve or boost curve - either or both of them must be severly retarded at the top end to give acceptable PCPs to stop the engine from going bang.Ideally, you want something like Saab developed, which was a variable compression engine - now THAT was
. dont know what came of it tbh,as for the rest . ok
11-04-2006, 05:31 PM
#135
Saab are still working on variable compression engines.
Holy grail i reckon
What we need is solenoid operated valves for fully mappable "cams" and then mappable CR to go with it.
10:1 off boost 6:1 at 3 bar, 40mpg, and happily ever after
Oh and all installed on a 3 litred scaled down version of the LS1 with DOD!
Holy grail i reckon
What we need is solenoid operated valves for fully mappable "cams" and then mappable CR to go with it.
10:1 off boost 6:1 at 3 bar, 40mpg, and happily ever after
Oh and all installed on a 3 litred scaled down version of the LS1 with DOD!
11-04-2006, 07:31 PM
#137
Originally Posted by GARETH T
i want a variable compression, camless engine 
If the valves were operated with enough precision, you wouldnt need a throttle flap either of course!
Just fly a by wire variable resistor
11-04-2006, 07:37 PM
#138
PassionFord Post Troll
Originally Posted by TM
What comps have you tried, also how do you know what retard phil is running
11-04-2006, 07:40 PM
#140
Professional Waffler
Originally Posted by chip-3door
Originally Posted by GARETH T
i want a variable compression, camless engine
If the valves were operated with enough precision, you wouldnt need a throttle flap either of course!
Just fly a by wire variable resistor
11-04-2006, 07:49 PM
#141
PassionFord Post Troll
Originally Posted by Bosch-Man
Mike it starts in singles but as the revs rise so does the advance to double figures ...so not single all the way!
As i said you need to drive mine and compare it to your lo comp engine...you will find mine massively more a ROAD car engine than yours was!
Remember i had a lo comp version too.
...so not single all the way!As i said you need to drive mine and compare it to your lo comp engine...you will find mine massively more a ROAD car engine than yours was!
Remember i had a lo comp version too.
This is how the norwigiens (spelling) seem to get away with huge horsepower. high cr, wild camed engines???
11-04-2006, 08:00 PM
#145
PassionFord Post Troll
I had a chap from lotus come to pick up a dash the other day said they ahve a cylinder up there with solenoid valves that they can test any cam profile on. He said the technology will hit the streets soon but in diesel truck engines to begin with as the valve gear/coils is still very big/heavy
11-04-2006, 08:21 PM
#146
PassionFord Post Troll
Originally Posted by chip-3door
Originally Posted by Garage19
Doh! Seems you all picked up on that one. That wil teach me to post before reading the whole thread!
11-04-2006, 09:33 PM
#147
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Originally Posted by Garage19
This is how the norwigiens (spelling) seem to get away with huge horsepower. high cr, wild camed engines???
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