Clifton
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Posts posted by Clifton
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What was wrong with your 7M Z? Did it ever run? If so I think you would already have the answer.
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There is not more air exiting the engine during combustion. There is however, much more volume.
Uh, air, volume, whatever. I think I said that. "Fuel has energy and that mixed with oxygen and ignition makes an expolsion that produces alot more volume"
The mass that goes into the engine is the same as the mass that leaves the engine. During combustion, much heat is added through burning of fuel which causes the air to expand greatly. This is where you are getting confused. Even though the air now occupies more volume, it is still the same mass. This is what I mean when I say that heat makes the turbo spool.I don't think I'm confused. Mass = volume.
mass
noun 2
Definition: measurement
Synonyms: bulk, dimension, extent, greatness, magnitude, size, volume
Source: Roget's New Millenniumâ„¢ Thesaurus, First Edition (v 1.1.1)
Copyright © 2005 by Lexico Publishing Group, LLC. All rights reserved.
I would think four years of mechanical engineering classes and $50,000 in tuition would mean something to someone.Might mean something to your employer.
The STS system however' date=' uses a much smaller AR ratio (smaller nozzle). The downside of their system is that all of that heat energy is lost in the piping to the turbo. Remember, that you are burning Y amount of fuel and their is Z amount of energy produced in this process. This burning of fuel creates heat and if you let that heat escape without harnessing it, you are losing potential to use it.To make the turbine spin, there is the a given amount of energy needed. In the conventional system, this energy comes from the heat of the exhaust. If you allows that heat to escape (STS system), then the energy needs to come from somewhere else. This comes from pumping losses in the engine. As the exhaust gas leaves the engine, it is really hot. As it travels towards the rear mounted turbo, it cools down and the pressure drops. To bring this pressure back up, STS uses a smaller AR ratio (small nozzle) to bring the pressure back up. This pressure energy has to come from somewhere and it comes from pumping losses in the engine. On the exhaust stroke of the engine, more energy is required of the pistons to push the exhaust out. Energy is not free, cannot be created or destroyed. It is your choice as to whether or not you want to use what is already given to you. [/quote']
STS uses a .81 a/r on there LS1. According to you that's a "much smaller a/r". Are you kidding? What, in your engineering opinion would be good for a 6 liter street car with optimum heat? 1.15?
So what you are saying is. It is the heat that is needed to expand the air/volume/mass/whatever to produce even more volume/air mass/whatever and it's this more volume/mass/air that spools the turbo and this is what is lacking in the STS kit.
Where I say it is the combustion process that is giving the extra volume/mass/air/whatever, and the heat is just a byproduct of combustion. So it is still the volume that is what we are looking for in the end. Ok.
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Do you have any clue as to fade resistance and performance compared tot he 12.2" wilwood AZC kit? Weight? Thanks.
Pads have an ideal operating temp. You can get different compound pads to suit the temperature you will be using the brakes at most. Wilwood makes several pads that fit a Superlight caliper. A full race pad will not have good cold stopping power on the street when cold, just as a lower temp street type pad would be prone to fade on a road course with a high hp car.
Re caliper flex, it can be felt as a sort of soft, springy feeling under hard high speed braking. But of course other brake problems can also show up as a similar feeling.No way you can feel the caliper flex. I can go push on any brake pedal and feel a springy feeling, it's the way brakes work.
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There are 8 second Supras and Vipers using IRS.
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Clifton' date='
"If you shut your ignition off with your foot in it obviously it will obviously loose spool. Cylinder pressure under load is over 1000 psi. That's alot of volume that is lost. "
An engine is a constant displacement pump. If you shut down the ignition, the engine is still turning and therefore still drawing in air and pumping it out the exhaust. Yes, the cylinder pressures do indeed drop, but that is not because of a loss of airflow. Cylinder pressures drop because there is no combustion (heat creation) in the cylinder chamber. Cylinder pressures w/o combustion are ~150-200psi and with combustion ~500-1500psi depending on throttle opening and boost.
The only difference is boost comes from the amount of heat that is being ejected through the exhaust. With ignition off, you still are pumping the same amount of air, just the air is cold. You get no boost. With ignition on, you are pumping the same amount of hot air and you get your turbo to spool up. You are correct in that it does take an amount of air to spool the turbo, but that air must also be hot. Remember that work is being done by the turbo and must come from somewhere. The compressor side of compressing the exact same amount of air as is being released through the exhaust side. What goes in must come out. This is not theory, it is the laws of conservation of mass an energy. If it was mearly air velocity driving the turbo, then the same amount of power would be transmitted to the turbine as the compressor would consume to pressurize the intake. That assumed a 100% efficient thermodynamic cycle, which is not the case. The extra energy comes from the temperature difference between the inlet to the turbine and the outlet of the turbine. If you still do not understand, I can reference some thermo equations and diagrams to help. I am at work now and do not have access to my thermo book. (I am a mechanical engineer)
[/quote']
There is more air exiting the engine when during the combustion. Fuel has energy and that mixed with oxygen and ignition makes an expolsion that produces alot more volume than if there were just air alone being pumped thorugh. The fact that the exhasust is hot is just a byproduct of the combustion. Someday when I'm retired and bored I might intercool my exhaust and hang the turbo out back like STS to show that it is volume and velocity the spins it, just like any other driven turbine(Electric generators on dams, ect).
what are some other causes of lag? in a small turbo like a stock T3. Obviously' date=' restrictive exhaust, and I guess retarded timing can increase lag, but what else?what effect does fuel mixture have on lag? [/quote']
What are you talking about, lag on the stock T3.
How much faster do you want it to spool, off idle? ALL turbos have lag. Try a postive displacement SC. To answer your last question though. Peak tuorque occurs around 13.2:1. More power, more exhaust, faster spool. Look at any dyno with equal motors and turbo and you'll see cars that run richer spool slower. This is not therory. -
I know the Q45 uses the RE4R03A trans. I have heard the Z32's do too but can't find the link I had.
On the weight thing.....I would estimate the Z32 to be right in the 125lbs neighborhood. It weighs more than my GF! lol!
I can toss around a Z or ZX 5speed pretty easy' date=' but the Z32 (92 NA) was a wee bit harder to lug around the garage and in and out of my trunk.
on the auto note....
what about a Q45 transmission? cant remember where, but I ran across a website for a guy running a hot build with something ungodly like a 250 shot of Nitrous in his q45, he DID have the transmission upgraded by level 10, I beleive. He was running low low low 12's in that pig of a car (4000lbs I would imagine), full interior and everything.
or the maxima 4 speed auto rebuilt using Starion internals? From what I have read, they are the same transmission, its just that the starion trans was built using much stronger parts.[/quote']
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Clifton I am using something similar to this http://cgi.ebay.com/ebaymotors/Rising-Rate-Fuel-Pressure-Regulator-FPR-30-70-psi-Adjs_W0QQcmdZViewItemQQcategoryZ33742QQitemZ8019650720QQrdZ1QQsspagenameZWD1V#ebayphotohosting
' date=' I am using stock 280ZX turbo injectors, i thought i would need this product so as to add more fuel when boosting, are you saying the stock FPR is all i needed? Dang, if that is the case I wish i new it before I bought it.
Appreciate everyones help on this.[/quote']
The fpr you got on ebay is the same as the stock one, 1:1. It just adds 1 psi fuel for 1 psi of boost to compensate for the manifold pressure that the injector is injecting into. Raising rate fpr's add additional fuel. I would probably get a wideband next.
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Are you using N/A injectors too? What's wrong with the stock FPR? Stock is 1:1. If you are on stock n/a everything you will need more fuel and a 1:1 will only compensate for boost not extra enrichment which it sounds like you are looking for. You'll need a rising rate regulator (greater than 1:1). Or addtional injectors.
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Clifton' date='
I must say that your theory on boost could not be any more incorrect. The amount of air flow does indeed create more boost, but it is the heat that is the main driving factor. As the hot exhaust air goes from high pressure (before turbo) to low pressure (after turbo) it is much cooler. This change in energy is what is transfered through the turbine. Simple thermodynamics and turbine theory. A quick way to prove this... take you car up to fourth gear, build full boost. While you foot is still in the throttle (don't let up) reach out and turn your ignition off. Your boost will drastically drop even though your engine is still pumping just as much air as before.
The way to tune for fast building boost is the same way to tune for power. Correct air/fuel ratios and proper ignition advance for power is also correct for building boost quickly. These values are dependent on your setup and how much boost you are running.
-jeremy-[/quote']
If you shut your ignition off with your foot in it obviously it will obviously loose spool. Cylinder pressure under load is over 1000 psi. That's alot of volume that is lost. According to your theory, STS systems shouldn't work very well either. The heat created at 3k and 6k rpms is the same but at 3k you will have quite a bit of lag due to the low exhasut volume. Try holding a propane torch on the turbine wheel and see how fast it turns, then use room temp compressed air. Correct afr's and timing build boost faster because you are making more power wich produces more volume. Just like a 5L motor will spool a given turbo faster than a 3L motor at the same rpm. More exhaust volume, not more heat.
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Exhaust flow spools turbos not heat. Heat is just a byproduct of power. More timing will make more power. More power = more exhaust, more exhaust flow = faster spool.
If you have 12 psi by 3100 rpms I wouldn't worry. When will you be below that rpm when racing or really in it? In 4th I can get 5 psi by 3k and I thought mine spools fast for it's size.
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Damn that's fast.
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And where might one find this rebuild kit for the stock 280ZX turbo???
I need to rebuild mine also...
Kinda far for you but Az Turbo. 3445 N 29 ave. 602-253-9953, Joel is the guy. I don't know of any shops in the Mesa area.
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I didn't read all the post but.
I did need to space out my wheels before I had my CO's on and I didn't have the studs for spacers and didn't need or want 5/16" spacers. I went to ACE with my cailpers and got 10 washers and made sure they were within .001" of each other. They were .078" thick. I ran them for about a year without any problems until I got my coilovers on and took them off.
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It's made with a radiator core. Every intercooler core I've seen has some kind of turbulators(sp?) in the tubes.
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tightens the turning radius.
How so? maybe I'm missing something but without increasing the wheel angle or shortening the wheel base I don't see how the turning radius would be effected.
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AZC http://arizonazcar.com/lowarms.html
You can also use centric bushings to move the stockers out about 1/4". I cut and lengthend mine 10mm.
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If you do plan on road racing and it makes good power you will use 5th gear if the track has a decent straight. I know there would be no way I could run a 4 speed.
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Uh, why do I need to? Jeff P did it, and had 23/23 as I posted above. I will ultimately be running his setup turbochargerwise on my black car using a standalone EFI system, so given I have seen his testing setup I trust his numbers.
I guess you don't need to. Different turbos will have different power potentials and will have different back pressure at the same boost. I have no idea what Jeff P has. Unless he runs doesn't run an intercooler or was comparing his turbine pressure to pre intercooler pressure I don't see how he was even, but If it was it was.
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What's yours need? Just bearing and seals or did the compressor wheel get damaged? You can get a rebuild kit for under $70. It's not hard to do.
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Ya, any motor swap will put you in E mod. If you are mainly after a fast/fun street car first, fun auto x car second it shouldn't matter. Me and a friend run E mod, motor swap, tires ect. Not as fast as most E mod cars but faster than most autocross cars and faster than any car on the street running auto X.
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I just don't see a car rolling if in first gear unless on a 45% incline. The P brake on my truck never worked, I ended up removing the cable when I shortend the wheel base. I used 1st gear for a P brake the entire time I've owned it, about 7 years. It never once rolled, on the street, rockcrawling, anywere. This wasn't a light 2500 lb Z. It weighed 4300 lbs the last time it was on the scale. Only a 3.0 V6 so there isn't alot of motor holding it.
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If the engine weight were equal and the 2.5 was turbo and the 302 ci was n/a and bothe made the same power. The V8 would be a better choice. Your torque will be available at lower rpm without lag. This would help alot foe auto X.
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Don't know the brand of stripper you are using but try Mar-Hyde Tal-Strip II Aircraft Coating Remover Spray. Jolane did a test on a bunch and this was good. I have used it many times when I painted my car and I found it's better than the gel.
On the battery tray area. I sand blasted mine with a harbor freight pressure blaster. I had alot of rust on and under mine. I then used Rust Mort on anything that looked even a little rusty.
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Kinda tough to pull the carrier bearings to shim underneath them without a puller tool like the one pictured on this page: http://www.ringpinion.com/default.asp?pid=6&pageid=80[/url'].
How much faster do you want it to spool, off idle? ALL turbos have lag. Try a postive displacement SC. To answer your last question though. Peak tuorque occurs around 13.2:1. More power, more exhaust, faster spool. Look at any dyno with equal motors and turbo and you'll see cars that run richer spool slower. This is not therory.
I'm so lost... need some help
in Brakes, Wheels, Suspension and Chassis
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I've had no problems with the stock LCA's. I run eccentric inner bushings, just to pull it in a little to run a 275 tire, other than that, stock front rubber diff mount with a steel limiter, rubber outer lca bushings and poly mustache bar bushings. I've only broke a driveshaft U joint. I would run 1310's and maybe CV's if it's going to see drag use with DR's. The torque is what breaks the parts.
NHRA doesn't care what you have or how much you make, just what your times are. 11.5 and faster you'll need a cage. Some tracks (atleast here)aren't as anal about the rules and let mid 10 sec street cars run without cages. Just a driveshaft loop is all you need to run up to an 11.5.
I'll be following you in the VH turbo swap soon.