Monday, September 04, 2006 - 09:43 pm, by: Mick Mielczarek(Eta04)
here are some pics of the setup up for my soarer, its the 1uzfe running two t28 ball bearing turbos, these are old pics and will update new ones tomorrow! the set up with bigger injectors and motec computer we will be running at 15 psi with forges of course we should be looking around the 650 hp mark!!!
Monday, September 04, 2006 - 10:24 pm, by: Clinton Trueman(Clinton8002)
nice. only one problem i can think of and that's the legal side of having a V8 with turbo. but I'm not positive on that. but i would love to see it fly!! if u want stupid but fun (and don't mind getting a new engine) you could always convert the car to gas but directly inject the gas into the turbo. that way you can run rediculus amounts of psi as the gas keep it cold. I'm not real serious bout someone doing it as people watching will probably not find you alive at the end.
Tuesday, September 05, 2006 - 09:17 pm, by: Cihan Aday(Cihan)
The two turbos go the opposite way, or ones sitting on the desk?
Looks mean Love to see it rolling along.
I think you'll find that compression is going to be a major PITA if you're trying to achieve 650hp. Thats a bold statement in my books, hopefully you have the time and resources to make it work.
All you need now is to fabricate an intake manifold setup utilising a single 65mm throttle body per bank. You could use a twin entry frontmount made for the 300ZX to keep things neat and tidy
Keep us updated, especially with tuning progress.
Cheers, Cihan.
Jeff Smith DieHard NSW TT Limited :-) equiped toyota torsen diff
Monday, December 04, 2006 - 01:59 pm, by: Rehan Bandara(Parsec)
t28s seem a little small for 2L spread across 4 cylinders at 15psi. Have you consulted the turbo maps?
I'm very interested in what kind of intake manifold you'll be using. That position can afford you a pretty simple and elegant design.
And yeah, i'd be worried about the turbos and exhaust manifold getting rained on...
You could have two raised sections on the bonnet with two scoops and two big pods poking straight out into the free airstream. Might need to think about the clearance between the bonnet and turbine housing though, as the carbon fibre could melt and delaminate (i know you can get it heat proofed and fireproofed for industrial situations, but i'm not sure how viable that is for a custom fab bonnet).
Tuesday, December 05, 2006 - 10:00 am, by: Mark Paddick(Sparks)
Cihan Aday wrote on Tuesday, September 05, 2006 - 09:17 pm:
I think you'll find that compression is going to be a major PITA if you're trying to achieve 650hp
I honestly don't understand that. Given that the engine can withstand the cylinder pressures to make 650HP surely it makes no difference how that cylinder pressure got there? Big compression, low boost or low compression, big boost? The cylinder pressures are still the same or the power would be different? Correct me if I'm wrong but I don't see how I could be.
In fact with big compression and small boost the intake temps should be lower and therefore make the same power at lower cylinder pressures as it is the difference in pressures (absolute) that makes the power not the peak values and all will be lower at lower temps.
I do know which I prefer to drive and it ain't huge boost.
Tuesday, December 05, 2006 - 11:22 am, by: Rehan Bandara(Parsec)
It can withstand those kinds of cylinder pressures? what makes you come to that conclusion?
I would have thought that without forced induction, regardless of the cam profile and compression ratio, the cylinder pressures would be at quite a vacuum at bottom dead centre. In fact, they have to be.
The cyclic compressive stress on the rods will increase with higher pressures under the compression and power strokes.
Tuesday, December 05, 2006 - 12:25 pm, by: Mark Paddick(Sparks)
WHAT??????
Go back and rad what I wrote again!!!!!
Not you Lew.
Neither case I was talking about is NOT forced induction. Just boost and compression changed, not taken away.
The cylinder pressures will, actually be lower for a low boost high compression engine but as , as you say, it starts from below zero the ABSOL:UTE pressure is and must be the same for it to be making the same power.
If someone KNOWS why this would not be true I would like to find out.
Tuesday, December 05, 2006 - 12:43 pm, by: Rehan Bandara(Parsec)
i read it many times. maybe i'm still misreading it. no offence, but it's a bit hard to understand.
I'm not sure what you're getting at?
All other things being equal, the same pressure at bottom dead centre does not result in the same amount of power. The power is dependent on the amount of compression subsequently imparted on the fuel air mixture by the piston after the intake stroke, and all of the combustion dynamics and losses during the power stroke.
A factory trim forced induction engine is likely to compress the fuel air charge less using the pistons as the absolute pressure at bottom dead centre is already reasonable under boost.
The same amount of power is generated by the same absolute pressures at top dead centre, regardless of induction method (ignoring frictional and compression losses and just looking at the power stroke).
I thought we were talking about forced induction here, where all things aren't equal.
Tuesday, December 05, 2006 - 12:58 pm, by: Mark Paddick(Sparks)
I did not say that the two had the same pressures at bottom dead centre but that the ABSOLUTE pressure i.e. the difference between minimum and maximum pressures after compression is the same in both cases. Therefore the power produced is equal. And must be so or I'm missing something magic.
Both engines are forced induction. One has high boost and low compression. The other has high compression and low boost. If I'm right both make exactly the same peak power.
That is the question.
In other words I want to force induce an engine that was N/A without decompressing it first 'cos it costs too much.
Tuesday, December 05, 2006 - 01:20 pm, by: Rehan Bandara(Parsec)
the difference between the minimum and maximum pressures before and after compression (bottom dead centre and top dead centre)?
All that matters is the the temperature and pressure at top dead centre relative to the atmosphere... if we're talking about the amount of power produced by the power stroke.
If we're talking about the amount of power produced by the engine as a unit, then the compression ratio matters as the engine has to do work to compress the gas from bottom dead centre to top dead centre.
The thermodynamics of the cycle are such that a higher compression ratio results in more power, however if this compression is achieved through turbocharging rather than what you are referring to exclusively as "compression" (piston compression), the engine will produce more power.
All things being equal, for those two engines configured to end up with the same pressure at top dead centre (either through cylinder compression or turbocharger compression), the one that relies on the turbocharger will be more efficient, as the turbomachinery is more efficient at compression than the pistons for a few reasons.
Of course, an engine configured to do less piston compression will invariably have a shorter stroke, and thus use less of the energy from the power stroke... This is okay though, as it means the exhaust pressure is higher than it would otherwise be, which facilitates driving the turbine faster, harder and less laggily.
Tuesday, December 05, 2006 - 01:48 pm, by: Mark Paddick(Sparks)
No it won't have a shorter stroke as its the same engine and no matter what deck height or piston configuration the stroke is the same.
In other words we are talking about the engine in the first post in this thread but with either a totally stock engine and low boost or low comp pistons and high boost. The former is obviously going to be much cheaper.
Is the former feasible; must be. You can get more power with cams without it going 'bang' so why not a turbo? Gramps is getting well over 200kW now.
If the answer to the question I posed is no, then why?, and by how much?, and will it stop it from working reasonably. Obviously since we're talking a stock motor the power isn't going to be huge so limit both engines to 220kW. How well do they compare? Is it only a kW or two or huge?
I think it would be worth a try if it didn't cost too much. Maybe a single turbo to keep costs down. If it doesn't work then I still have a stock engine to play with and haven't lost too much. And you can always flog a turbo on ebay.
Tuesday, December 05, 2006 - 04:18 pm, by: Dan McColl(Hoon)
Rehan Bandara wrote on Tuesday, December 05, 2006 - 12:43 pm:
same pressure at bottom dead centre does not result in the same amount of power
Absolutely nothing to do with cyl pressure at bottom dead centre. Pressure at bottom dead centre does •••• all for anyone. It's pressure at TDC that does the work. You know, just after the spark plug fires.
If this peak pressure is the same after the plug ignites then the power output of that cylinder will be the same, regardless of the compression ratio or boost level or any other •••••
Tuesday, December 05, 2006 - 04:40 pm, by: Mark Paddick(Sparks)
Not being trained in this field and just thinking about it I would have thought that it would be the difference between the two pressures that matters. If the pressure is the same at ignition in two cases and they have different pressures at BDC surely the output isn't the same? Wouldn't the one with the higher pressure at BDC have to work against that more?
Tuesday, December 05, 2006 - 04:56 pm, by: Tim Appleton(Timbo)
The only advantage I can think of in either system is that you have more boost with which to drive the cylinder down during the intake stroke on a high boost low compression setup. Otherwise both systems appear mechanically similar in my mind.
Previous
