View Single Post
Old 03-29-2012, 04:57 AM   #9
pwpanas
Supra Owner
 
pwpanas's Avatar
 
Join Date: Oct 2005
Location: GA, USA
Posts: 2,209
pwpanas is on a distinguished road
Default

Quote:
Originally Posted by jzzrs180 View Post
if a sports car uses increased air (the twins) to increase the cylinder pressure, you would need a high octane gas like 93...
Sorry gotta stop you right there. 93 octane (r+m)/2 pump gas is only 88 motor octane. Rather pathetic, actually. High octane fuel is something like this:
http://www.vpracingfuels.com/page499588.html
Quote:
Originally Posted by jzzrs180 View Post
...to be able to ignite it at the right time, and burn that off efficiently.
But I guess what you are saying is, (if I have you right), that if I were to manage a good bpu I wouldn't have to worry about air:fule ratio because your the ecu reads your increased air automatically and auto corrects your fuel consumption?...
Actually, I'm saying that and a whole lot more. Too much boost using lower octane fuel explodes (i.e. detonates), it doesn't burn...which blows holes in your pistons.
Quote:
Originally Posted by jzzrs180 View Post
...So then, can you explain how and where do I get this mixture of higher octane fuel, and is it stored in the main fuel cell together?...
Yep, or you can inject it separately - your choice.
Quote:
Originally Posted by jzzrs180 View Post
...What is that ratio lol?...
Lol? Tell me the boost you want to run and I'll tell you what ratio to use. Not sure what the Lol is about...it's pretty simple.
Quote:
Originally Posted by jzzrs180 View Post
...sounds like a pain in the ass to fill up..ha....
Not nearly as big a pain in the ass as swapping your pistons out after blowing holes in them. HA!
Quote:
Originally Posted by jzzrs180 View Post
...controlling the cam gears with opening n closing of the valves in relation to TDC is basically how to improve hp, but why?...
Again, you don't improve hp, you just move the peak efficiency curve of the engine so you can make more max hp. You give up a bit of bottom end hp and torque, but that's easily corrected by a downshift.
Quote:
Originally Posted by jzzrs180 View Post
...what are the popular degree(s) for a bpu, with say.. 15psi?...
http://www.mkiv.com/techarticles/cam...all/index.html
"On exhaust gear, retard -3 (deg.), on intake gear, advance 1 (deg.)."
Quote:
Originally Posted by jzzrs180 View Post
...what are your top 3 favorite systems or the 3 most popular?...
To be honest, my favorite was the one I designed and sold, but don't anymore. Sadly, the higher-end components I used didn't allow it to be sold at a competitive price. Regardless, here's one that I'd be comfortable recommending:
http://www.spracingonline.com/store/..._MKIV_Supra/17
Quote:
Originally Posted by jzzrs180 View Post
...And to clarify the thermometer thing, sorry I was saying I thought if you increase your hp past say 500hp that you would have to upgrade your cooling system, which includes radiator, water pump, piping, probably your fmic, and the thermometer, along with the fuel system, fuel lines, pump, filter, injectors..Since the stock system has trouble keeping up with the added power. Am I correct?...
No, I didn't say that at all. Actually, I'm pretty confused about how you could have possibly misread that into any of my posts. Weird. Perhaps you were thinking that a better cooling system would make low octane fuel burn cooler under high boost? If that's the case, then sorry it won't. The cooling system pulls heat out of the metal in the head and the block - which only has a minimal indirect impact on the combustion temperature. Think about it this way - let's say I'm running a Supra in Alaska in the wintertime. The Supra has a single turbo and is configured to push 30psi+ of boost. The ambient temperature is 75 degrees below zero. I fill 'er up with 93 octane (88mon) pump gas and within a few seconds I hit my 30psi of boost. What happens? Of course, this is a bad idea with a cold engine because I'll probably throw a bearing, but putting that problem aside for the moment, I'll still blow holes through the pistons because of detonation. The cooling system is completely irrelevant in this situation, because the metal in the engine is still bone cold. So even with a crazy-cold motor the combustion temperature and pressure and the low octane of the fuel are the important pieces of the puzzle. Get it?

Summary:
Either way, the entire oem cooling system (including the "thermometer" aka temp sensors) is just fine to well over 750rwhp.
The oem fuel system is an entirely different story - the US-spec Mkiv Supra Turbo's oem fuel system can only handle about 550rwhp max - if all of the components are in brand-new condition.
Quote:
Originally Posted by jzzrs180 View Post
...my guess is that it just means better response with your throttle at low and high rpms.. I just wanted a more clear understanding if you could clarify better....
Sorry don't know much about the oem Mkiv auto - hopefully another forum member can help you out here. Mine's a 6spd.
Quote:
Originally Posted by jzzrs180 View Post
...how, and where, and at what ratio do I make this fuel work for me?...
Depends on how much boost you want to run.
Quote:
Originally Posted by jzzrs180 View Post
...Eventually I'd like to hit those higher horse numbers like I already mentioned, but do I have to then switch to a single?...
Yep.
Quote:
Originally Posted by jzzrs180 View Post
...I have seen most nutty 1000hp Sup's (or some with a little less) possess single turbos, but also heard/seen a few that maintained upgraded twins as well, is that unnecessary because of cost to stay with twins?...
You can get "upgraded twins" but they're not longer sequential - they're parallel. Most don't go with this because that kit is more expensive and provides no tangible benefit over a single.
Quote:
Originally Posted by jzzrs180 View Post
...One of my ultimate goals is a strong, quickly responsive powerband all the way through with as little lag as possible starting at low rpm, yet still able to drive it like a regular stock toyota...
Sounds like you want to have your cake and to eat it too. Unfortunately big hp turbos don't spool up fast. It's just physics - a bigger turbo compressor wheel is heavier, and takes more exhaust energy via the turbine wheel to spin up. No one has figured out how to defy the laws of physics yet, so this rule always holds true.
__________________
Phil '94 Supra Turbo, 6spd, 'APU'+
Displacement is no replacement for boost.
Life begins at 30psi.


NB: Please consider posting any help requests in a new thread instead of asking me for help privately. About 99.9+% of the time, private help requests end up covering great information that could be very valuable to other forum members. If you have a good reason for needing the help request to be private, I'll consider it. If not, then why not give everyone else the opportunity to pitch in too, and/or learn from the information? Remember, there's no such thing as a dumb question. We're all here to help within this family of Supra owners.

Last edited by pwpanas; 04-01-2012 at 05:22 PM.
pwpanas is offline   Reply With Quote