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Z

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Discussion Starter #1
I have heard many people running single turbo upgrade with stock fuel system...is that safe? what is the limitation of stock fuel system?

on the side, does 1 bar of boost on large single turbo the same as 1 bar of boost on stock twin? do they require same amount of fuel?

thanx

Jonas
 

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Basically it takes more fuel to make more power. The stock fuel system has been reported to max out at 550rwhp. If you set your boost and tune for 520rwhp (just and example) than you are still within the stock fuel systems ability to deliver enough fuel. The problem arises when you have a boost spike, or something breaks and your boost goes up requiring enough fuel for 650rwhp. With the stock fuel system you can't deliver enough fuel and you have a lean a/f ratio which causes detonation and a broken motor. If you have an upgraded fuel system it can deliver the needed fuel and hopefully you will have time to let off before damage is done. Assuming your not running race gas and wanting 650rwhp in with the upgraded fuel system. :)

Keep in mind that stock twins will usually make around 420rwhp at 18psi (with a FMIC) and medium to large singles will make 500+ rwhp at the same 18psi. In the stock twin example you need fuel for 420rwhp and in the second example you need fuel for 500+ rwhp. The answer to your question is NO.

Later, Steve
 
C

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Discussion Starter #3
Jonas,

I run my SP60 on near stock fuel. I have removed the fuel pulsation dampener and increased the fuel pump voltage to 18v. I am paranoid as hell about breaking my car after blowing a turbo. I DO NOT WANT A BLOWN ENGINE. If you get good gauges, boost, egt, A/F, Fuel Pressure, and keep your eyes on them then you shouldn't have a problem. ALSO you need to tune your car conservatively. There is no sense in pushing your fuel system to the limits.

Also you must have your injectors cleaned and balanced. If one is clogged, kiss your engine good bye.

I would definatly stick with a smaller turbo, SP60 or less, or possibly a PHR Street, or Stage 1. Anything more and there is simply too much risk. Also it makes no sense to go any bigger on stock fuel because you will never be able to achieve the full capabilities of the turbo.

Things have worked great for me so far. I've taken it on a lot of hard pulls to over 140mph. My car was running a bit too lean in the upper RPM range so I didn't take it any further than that. I was afraid to tune my car myself, I had presumed that Lance at Toyomoto would be able to tune it for me.

Anyhow, after months of delay, I went ahead and tuned the fuel a little myself. Car runs like a charm now. I hope to get it on the dyno when I get back in town sometime in December.

Hope that helps some.
 

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Of course if your a roadracer there is a reason to go with a turbo bigger than an SP60 on stock fuel. If you want to run 510rwhp at the lowest boost possible, than the bigger turbo makes sense.

I am doing an SP63 with stock fuel. I am so going to blow my motor. :rolleyes: Keep in mind that most stock turbo cars could blow their motors with stock turbos if there boost isn't controlled properly. Try spiking to 18 psi on a stock RX7 TT. :eek: We have one of the few cars that you can "pull the hoses" on and not blow something up.

Later, Steve
 

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Steve, has anyone done 550 rwhp for long periods of time running conservative a/fs (lows 11s, at least for pump gas road racing)?? Doesn't sound safe to me. And from what I hear from RC engineering, pushing the injectors past 80% duty is dangerous as well.

Perhapes you could get by with raising the fuel pressure, but that can get dangerous too.

Since the SP63 can make 540-550 rwhp at 18 psi, I'd just use a manual boost controller set lower for maximum reliability, not that EBC you have Jon.
 
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Discussion Starter #6
I can always insert a MBC also so that if I do have a crazy boost spike the MBC will catch it.

I like being able to turn down my boost whenever I want. :), a little redundency never hurt.

At least I didnt get the AVC-R :).
 

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I will probably tune for 11.6:1 richening to 11.2:1 by readline. I am currently only hitting around 60% duty cycle and my car dynoed at 438rwhp. I hit in the low 60% range on the street where I am probably making slightly more power. I should be able to add about 18% more fuel before I get to 80%. This would put me in the 515rwhp range or close. That is what I will tune for. Basically I will not run more than 18psi or 500rwhp on the roadcourse. In reality I will probably run about 18psi or 515rwhp (remember I have stock MAF, stock intake manifold, and stock cams) on the street and around 17psi or 495rwhp on the roadcourse. I will have an actual alarm wired to my Greddy boost and EGT gauges to let me know if either one go above what I consider safe.

Phillip Long was running 550rwhp at a 11.2:1 a/f when he was running NOS. Of course he wasn't doing this through the stock injectors, but he was doing this with the stock pump, and stock lines. I assume I will have to do the fuel pulsation dampner bypass.

Later, Steve
 

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That still seems a little low hp for that boost level, but what do I know, is this with the .58 a/r?

IMO it would be better to wire the EGT warning to the '!' light, can you really hear an alarm w/ a helmet on and the windows down? But then I would have the open wastegate noise as well :)

What did you monitor duty cycle with? The AEM ECU might allow us to do some cool things, maybe lower boost if the duty cylce goes over 80%
 

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I actually have a light and a buzzer. :) I was using the AVC-R or Super AFC. The turbo is a .70 a/r. I will basically tune to these power levels. If it is at a lower boost level, than that will be even better.

Later, Steve
 
Z

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Discussion Starter #10
so everyone here is SP turbos....I am thinking of TO4R, anyone know what kind of power I can ake with stock fuel and To4R?

thanx

Jonas
 

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hey all,
I am looking at doing the fuel dampener bypass....I was just curious if I have to take off the upper manifold to do this. It looks as if I will probably have to. But just making sure on this. Also I assume I can run an upgraded fuel rail and injectors along with a fuel regulator after the stock fuel filter....basically everything will be upgraded after the fuel filter. Anybody who has done this, feel free to add your advice.
SH
T78
 
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