Which one should i go for ? A Steel Strut brace or a Alloy Strut Brace?
Steel = heavier but stronger
Alloy = lighter but weaker
Diesel Power !!!!!
Moderator: RichardW
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Twiss</i>
Which one should i go for ? A Steel Strut brace or a Alloy Strut Brace?
Steel = heavier but stronger
Alloy = lighter but weaker
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
On a road car a little bit of weight isn't going to be noticable but the alluminium alloy material will be (200GPa/70GPa) almost 3 times less stiff than a steel one - if it is the same shape!
Still would you notice that?
It would weigh about 8[g/cm]/2.7[g/cm] ~ 3 times less. Once again only if it was the same shape.
Which one should i go for ? A Steel Strut brace or a Alloy Strut Brace?
Steel = heavier but stronger
Alloy = lighter but weaker
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
On a road car a little bit of weight isn't going to be noticable but the alluminium alloy material will be (200GPa/70GPa) almost 3 times less stiff than a steel one - if it is the same shape!
Still would you notice that?
It would weigh about 8[g/cm]/2.7[g/cm] ~ 3 times less. Once again only if it was the same shape.
itdontgo, the main limiting factor of the diesel engine is the slow combustion and flame propogation of the actual diesel mixture. This is what really slows them down and stops them revving like a petrol. The new higher pressure pumps and direct injection atomise the fuel mixture better and therefore it burns quicker. There has never been a problem with getting the injection pressure high enough with the mnechanical pumps as far as I know? It could always squirt the fuel in just fine, but the design with the swirl chamber does not really rely on that anyway. Just spent some time investigating diesel engine vs gdi (direct gasoline injection) and never came acccross that one?
When you say its not worth changing the cam, i beg to differ. You dont see the na xud's not starting due to losing compression through the inlet? I beleive they do also have a dgree of overlap, and certainly have a longer duration than the td ones. This just means that you can squeeze a little more power safely from a very cheap camchange and timing and nothing else. When you have got to the point where you cant increase boost or fuelling anymore, and you have a good intercooler, its worth a try.
Why would having a little overlap hamper the valves? Are you saying that they will touch each other, or the piston??? I know there is no comustion chamber to speak of, but there must be enough room to have both valves open a little bit at the same time? And why would leaving the inlet open a little bit hurt so much? ALL cars (even diesels) employ this technique. Some of the air gets forced back into the manifold and helps mix the next charge and produces pulses that actually help the next cylinder. Ok none of this would benefit as much as it does an a petrol engine, but the same technique still applies.
I know the diesel engine relies on compression to get its higher VE but, in all honesty, these engines arent that slow! Max torque on the na cam in the na engine is produced at 4700rpm! When you think alot of petrol engines redline at 6000 rpm, and produce max torque at aroud 5000rpm its not far off. Alot of books compare diesel and petrol engines between big diesels like train and other very slow >1000rpm diesel engines. This is because they were written before diesels became poular in passenger cars. I think the 'fast flowing fluids' you describe can be found in the xud engine and used in the same ways. However, I agree that it will not show significant gains compared to filling the cylinders with more boost and fuel and keeping the valves closed.
Turbolag, The no2/methanol/water systems are very efficeint in theory, but in practice they are a pain in the arse. You have first got to find a place to put the bottle/reservior/pumps/controller, then spend alot of time getting it wrong and having blowups/powerdecreases/problems before it gets working. Then you have to keep refilling your system with the required fluid. Then you think, well I'll only use it sometimes, so whats the point?
With a turbo upgrade, you can increase boost whilst decreasing inlet temps, it will move the max torque a little further up (especially with the cam) but you will still benefit lower down due to quicker spool and no wastegate creep. And once its done, its done!! Dont need to do anything like filling stupid bottles every 1/2 a tank.
I think alot of people look down on upgrading the turbo because the main tuners dont really offer it as an option.
When you say its not worth changing the cam, i beg to differ. You dont see the na xud's not starting due to losing compression through the inlet? I beleive they do also have a dgree of overlap, and certainly have a longer duration than the td ones. This just means that you can squeeze a little more power safely from a very cheap camchange and timing and nothing else. When you have got to the point where you cant increase boost or fuelling anymore, and you have a good intercooler, its worth a try.
Why would having a little overlap hamper the valves? Are you saying that they will touch each other, or the piston??? I know there is no comustion chamber to speak of, but there must be enough room to have both valves open a little bit at the same time? And why would leaving the inlet open a little bit hurt so much? ALL cars (even diesels) employ this technique. Some of the air gets forced back into the manifold and helps mix the next charge and produces pulses that actually help the next cylinder. Ok none of this would benefit as much as it does an a petrol engine, but the same technique still applies.
I know the diesel engine relies on compression to get its higher VE but, in all honesty, these engines arent that slow! Max torque on the na cam in the na engine is produced at 4700rpm! When you think alot of petrol engines redline at 6000 rpm, and produce max torque at aroud 5000rpm its not far off. Alot of books compare diesel and petrol engines between big diesels like train and other very slow >1000rpm diesel engines. This is because they were written before diesels became poular in passenger cars. I think the 'fast flowing fluids' you describe can be found in the xud engine and used in the same ways. However, I agree that it will not show significant gains compared to filling the cylinders with more boost and fuel and keeping the valves closed.
Turbolag, The no2/methanol/water systems are very efficeint in theory, but in practice they are a pain in the arse. You have first got to find a place to put the bottle/reservior/pumps/controller, then spend alot of time getting it wrong and having blowups/powerdecreases/problems before it gets working. Then you have to keep refilling your system with the required fluid. Then you think, well I'll only use it sometimes, so whats the point?
With a turbo upgrade, you can increase boost whilst decreasing inlet temps, it will move the max torque a little further up (especially with the cam) but you will still benefit lower down due to quicker spool and no wastegate creep. And once its done, its done!! Dont need to do anything like filling stupid bottles every 1/2 a tank.
I think alot of people look down on upgrading the turbo because the main tuners dont really offer it as an option.
I ran an experimezntal home brewed water injection set up on my 400 TD and it worked a treat (needed tidying up and some fiddling with the metering, but the car went before the project was at full fruition) and it worked well indeed (especially well on the non inztercooled Rover) with astonishing performance gains on H2O. Mine was never dyno'd but yanks running jap diesels with such systems report 20-40% increase on H2O and more on a methanol mix. No turbo this side of a lottery win will give those gains on an XUD. Additionally, the motor remains perfectly tractable with the power/torgue curves up at all points in the rev range. Best bit was once the water was gone (about 2 days at 48 miles per day of X country driving for me) the engine reverted to perfectly normal running, unlike a sparker with would require the ignition retarding back to avoid detonation and major meltdown. Not an issue on a diesel with no advance. The lowered intake temps lead to lower EG temps and better running.
I'm not dissin' turbos (me likey blowers velly much) but the potential 'thrust gains v price' equation favours water on a mech injected oiler.
A pukka kit from Aquamist (or whoever) would be cheaper than a sporty turbo, give bigger gains, and be switchable on/off if desired, thus leaving the car in standard driveable trim if desired - apart from filling up every couple of days there's no downside.
I'm not dissin' turbos (me likey blowers velly much) but the potential 'thrust gains v price' equation favours water on a mech injected oiler.
A pukka kit from Aquamist (or whoever) would be cheaper than a sporty turbo, give bigger gains, and be switchable on/off if desired, thus leaving the car in standard driveable trim if desired - apart from filling up every couple of days there's no downside.
very interesting turbolag, what did your system comprise of? where did you inject the water? into a hose or directly into the manifold? what type of suirters did you use? was it running all the time or boost or temp triggered?
Have you got a link or something whare it shows this type of system having a proven effect?
when you say that there was a gain just by using water, this is just due to the cooling properties, increasing the density of the mixture? or is there something i've missed?[B)]
I've always been sceptical about this water injection thing after seeing a few systems (admittedly on petrol cars) do nothing positive at all, no lowered temps etc. I once read that a bmw engineer from back in the heyday of the 1500bhp 1.5 litre turbo F1 cars had said "we spent some time experimenting with h2o injection systems, but have come to the conclusion that water doesnt burn"[:D]!!
I'm game to give it a try if its as good as that. I did see that top gear once when they nitroused a golf tdi auto and it made a difference, but I wouldnt bother with all that expense and trouble on my car, imean its like £300+ for a nitous system without fitting, and you still need to keep paying for the stuff, it defies my projedt logic of fast and economical.
I do however have an intercooler water spray system with PIC18f452 controller, twin pumps and high pressure nozzles that i made just sitting around after I took it off my race car[;)] This could be used to inject water into a low pressure part of the system like before the turbo. Its also triggered by two temp sensors (ambient and inlet), and a duty cycle input that could be swapped for maybe a pressure switch.
Have you got a link or something whare it shows this type of system having a proven effect?
when you say that there was a gain just by using water, this is just due to the cooling properties, increasing the density of the mixture? or is there something i've missed?[B)]
I've always been sceptical about this water injection thing after seeing a few systems (admittedly on petrol cars) do nothing positive at all, no lowered temps etc. I once read that a bmw engineer from back in the heyday of the 1500bhp 1.5 litre turbo F1 cars had said "we spent some time experimenting with h2o injection systems, but have come to the conclusion that water doesnt burn"[:D]!!
I'm game to give it a try if its as good as that. I did see that top gear once when they nitroused a golf tdi auto and it made a difference, but I wouldnt bother with all that expense and trouble on my car, imean its like £300+ for a nitous system without fitting, and you still need to keep paying for the stuff, it defies my projedt logic of fast and economical.
I do however have an intercooler water spray system with PIC18f452 controller, twin pumps and high pressure nozzles that i made just sitting around after I took it off my race car[;)] This could be used to inject water into a low pressure part of the system like before the turbo. Its also triggered by two temp sensors (ambient and inlet), and a duty cycle input that could be swapped for maybe a pressure switch.
I dont know where you were getting your information from and I'm sure its all true but there is a definite issue with diesels and their compression which determines the cam profile.
The inlet valve doesn't stay open to pump a little bit of gas back out of the cylinder for the next stroke it does it because the gas flowing towards it has a large pressure head relative to the pressure within the cylinder. Therefore by staying open after BDC the momentum of the gas continues to fill the cylinder even though the volume of the cylinder is decreasing. The valve shutting and reflecting the pressure wave is what increases the plenum chamber pressure.
Obviously at low engine speeds the gas gets pushed out of the cylinder and there is less compression, less heat and problems igniting the mixture. As the engine is designed to go on for 100,000 miles then a little loss in compression is probably expected and so the cam wont be optimised but this is one of the main design factors.
I hope you have been reading academic texts (I cant think of any references off the top of my head) and not these misleading car magazines and websites...
If it wasn't written by a PhD then you can assume there is liekly to be some doubt as to whether it is a balanced accurate report.
The inlet valve doesn't stay open to pump a little bit of gas back out of the cylinder for the next stroke it does it because the gas flowing towards it has a large pressure head relative to the pressure within the cylinder. Therefore by staying open after BDC the momentum of the gas continues to fill the cylinder even though the volume of the cylinder is decreasing. The valve shutting and reflecting the pressure wave is what increases the plenum chamber pressure.
Obviously at low engine speeds the gas gets pushed out of the cylinder and there is less compression, less heat and problems igniting the mixture. As the engine is designed to go on for 100,000 miles then a little loss in compression is probably expected and so the cam wont be optimised but this is one of the main design factors.
I hope you have been reading academic texts (I cant think of any references off the top of my head) and not these misleading car magazines and websites...
If it wasn't written by a PhD then you can assume there is liekly to be some doubt as to whether it is a balanced accurate report.
on the topic of turbos though, how does a garrett gt20 vnt from a 2.5v6 passat for £150 grab you? Mounted on the standard xud manifold, bolting to the standard downpipe? It acts like a small turbo when spooling up, then opens the internal vanes to act like a large size turbo when on boost = less lag, less restriction, less temps. Hard to change the actuating system from vacuum/ecu controlled to mechnical pressure actuator though (done[:D]) and was also hard to get the oil drain pointing down as the vnt mechanism doesnt allow you to rotate the exhaust housing, but guess what, thats also done, total extra cost = £20 for getting it mounted on the original manifold as it is cast and i didnt have anything to tap it.
Mr Bump, have a look at http://www.waterinjection.info/phpBB2/ for further info. This site is off at the mo but should be back on in the next day or so.
Run water injection turbo diesel through Google and you'll finf loads of site, mainly Yank. Have a root through the forums and there is no end of posts from folk printing 'with' and 'without' dyno runs.
I used an Aquamist misting nozzle and introudced the water pre turbo. A misting nozzle is a must in the configuration to avoid turbo vane erosion. Mine was pressure triggered, intitially using a bleed from the turob to pressurise the reservoir, but this was pants, so I got an adjustable pressure switch from a mate who works with hydraulics, though Maplins and the like can also supply these cheaply. Pump was a BMW screenwash pump which I had in my box-O-poop and is fine for a pre turbo installation. With an intercooler a higher pressure pump would be needed for post turbo squirty antics.
H2O was indeed largely the upper limit in the old 1500 turbo F1 days. As boost rose, so did the water and the point was reached where the H2O was quenching the burn. On a diesel it slows the burn, but evens it and lenthens it and the expansion of the water provides more energy too, as well as a cooling effect. Add methanol to this (which diesels like velly much indeedy) and the results can be startling for little outlay.
Run water injection turbo diesel through Google and you'll finf loads of site, mainly Yank. Have a root through the forums and there is no end of posts from folk printing 'with' and 'without' dyno runs.
I used an Aquamist misting nozzle and introudced the water pre turbo. A misting nozzle is a must in the configuration to avoid turbo vane erosion. Mine was pressure triggered, intitially using a bleed from the turob to pressurise the reservoir, but this was pants, so I got an adjustable pressure switch from a mate who works with hydraulics, though Maplins and the like can also supply these cheaply. Pump was a BMW screenwash pump which I had in my box-O-poop and is fine for a pre turbo installation. With an intercooler a higher pressure pump would be needed for post turbo squirty antics.
H2O was indeed largely the upper limit in the old 1500 turbo F1 days. As boost rose, so did the water and the point was reached where the H2O was quenching the burn. On a diesel it slows the burn, but evens it and lenthens it and the expansion of the water provides more energy too, as well as a cooling effect. Add methanol to this (which diesels like velly much indeedy) and the results can be startling for little outlay.
Thanks, I will be having a good read through some of that stuff. Are you sure its safe to spray a methanol mix onto a hot turbo compressor?[:0] [:D]
Itdontgo, The inlet valve does many different things in many different situations, and my example is one of them. The extreme example of this is the miller cycle engine. The valve even stays open a while after there is an equal pressure across it. Just like really long duration cams do. I get my info from various texts whilst attempting to study towards a BEng in Automotive Engineering at University.
Itdontgo, The inlet valve does many different things in many different situations, and my example is one of them. The extreme example of this is the miller cycle engine. The valve even stays open a while after there is an equal pressure across it. Just like really long duration cams do. I get my info from various texts whilst attempting to study towards a BEng in Automotive Engineering at University.
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Wookey
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Hello people - I see I'm being mentionned 
With this NA cam in turbo engine setup do the tappet clearances change at all? I ask because they were all a bit high in activa's engine (30-60) rather than the stock 15/30. Having changed the cam to one with the correct end-drive for the vacuum pump I've reset them all to standard. Is that right? With bigger gaps the valves would open for a shorter time - I'm not sure how much, or what effect this would have...
With this NA cam in turbo engine setup do the tappet clearances change at all? I ask because they were all a bit high in activa's engine (30-60) rather than the stock 15/30. Having changed the cam to one with the correct end-drive for the vacuum pump I've reset them all to standard. Is that right? With bigger gaps the valves would open for a shorter time - I'm not sure how much, or what effect this would have...
Hi wookey,
Clearances will change, but if you use all the shims from the car that you took the cam from in the first place, you should get back to where you were. This is because the cam carriers are fitted to the engine in the factory and then the hole is bored through the head and carriers at the same time. This means that the carriers are specific to that head. The shims are then machine selected for the cam to get to tolerances, meaning the only close tolerance cut is the cut through the carriers/head saving money for citroen! Its also a pain if you cross thread a carrier! (i've done 2)
c
Clearances will change, but if you use all the shims from the car that you took the cam from in the first place, you should get back to where you were. This is because the cam carriers are fitted to the engine in the factory and then the hole is bored through the head and carriers at the same time. This means that the carriers are specific to that head. The shims are then machine selected for the cam to get to tolerances, meaning the only close tolerance cut is the cut through the carriers/head saving money for citroen! Its also a pain if you cross thread a carrier! (i've done 2)
c
Hi twiss,
Seems a bit expensive for me. What exactly are you getting? Find out what hes going to do and then try either Turbo Technics or Turbo Active (best bet). From memory, they were going to do a t2/t25 hybrid with 360's and some other nice bits for around £450 all in.
www.turboactive.com
Cheers
Seems a bit expensive for me. What exactly are you getting? Find out what hes going to do and then try either Turbo Technics or Turbo Active (best bet). From memory, they were going to do a t2/t25 hybrid with 360's and some other nice bits for around £450 all in.
www.turboactive.com
Cheers