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Discussion Starter · #1 ·
I've got a question which has put a sudden halt to my build.

Over the years I've spent endless hours reading through these forums and others to gain as much knowledge ontop of what i already know so that i know from peoples first hand experiences what happens when you mix product X with part Y and so on. But I've been getting alot of mixed answers when it comes to this question and i would appreciate it if the real educated nutters step in.

Question starts here!!
More and more frequently i see cars running very low times on very high boost.. on nothing more then pump fuel. 93 octane and the respected equivalent for the same fuel in the states (my understanding is that you guys have more choice and more ease of obtaining higher octane fuels then what other countries do)

For instance the thread below me is a member of these forums car running a nice 10 second pass without the assistance of meth spray or e85 fuel. He is running 93 octane and 30 pound. To E85 fuel's credit he does state he was getting knock.

http://www.supraforums.com/forum/sh...pump-gas-10.57-135.5mph&p=8389750#post8389750

Another notable member would be Jaimie price.

Speaking to him directly through a video he posted on youtube, he states he runs 27 pound on pump and when he feels like pushing it he sees 30.


The remarks I've seen smicker at people majority of the time in a fashion as if they were fools to run such high pressure with no knock repellent additive when ever somebody states their setup which substitutes 93 octane on its own without meth or straight e85.

I've been told its down to the tune, I've also been told is impossible and its suicide for your engine.

Can somebody chime in because I'm seeking the correct understanding and I'm having trouble finding answers on my own that are informing.


(For the record I've ordered and plan to run meth spray, not to any bias but just because its already purchased)
 

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In that link, the OP is from Iceland. Pump gas to him is 98oct. where as pump gas here in the states is 93oct. So that is why he was able to run 30psi on "Pump gas".

Personally, I would NEVER run 30psi on 93 oct. gas. You are def. asking for trouble if you plan on doing that!
 

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Discussion Starter · #4 ·
In that link, the OP is from Iceland. Pump gas to him is 98oct. where as pump gas here in the states is 93oct. So that is why he was able to run 30psi on "Pump gas".

Personally, I would NEVER run 30psi on 93 oct. gas. You are def. asking for trouble if you plan on doing that!
Your mistaken there if i may say so, all around the world, we quote our fuels on the octane reading. Here in Australia we have 98 oct at practically every pump in the country.

In the United states your fuel is not advertised rated on the octane reading but rather the AKI (average of the RON and the MON). So your 93 is the equivalent to about 98-100 octane.

You guys have better fuel!

Price of gas < Price of engine

/thread
I'm after information as to why people are getting away with running high boost for a long time on their car and getting away with it, not asking what is better.

In my mind i would stick e85 or run meth way before i every decided to push past 21 pound.. but i still itch for the knowledge as i rather know then forget about it all together.
 

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Myself, I am a fan of water/meth on the street, even though I can get 94 at the pump (canada). I am at 21 psi now, using water/meth and 94, and have plans for bigger injectors, and up to 30 psi. The water/meth is what makes me feel "comfortable" with those boost levels.
As I recall, some testing of 92 octane fuel resulted in a maximum torque output of approx. 180-190 lb/ft PER LITER of displacement before detonation, quite consistantly. That is assuming a good, detonation resistant head design, (like the 2jz, or honda b-series). I would have to look up the testing to get more exact, but that is the "guideline" that sticks in my mind.
 

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adammackintosh.net
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we cant just state that someone is running 30 psi on pump gas so why cant i.

theres gonna be many factors. i could probably run 60 psi on pump gas if i had 7:1 CR and retarded timing at full boost

if i were you i would run that meth, and tune it to zero knock with as much timing+boost as you can get. and not worry about these random dudes off the street that may or may not be revealing all the information you need AND have potentially completely different motors and mods.

for the record im running 24 psi in 94 AKI octane and two 550ml/min nozzles spraying 100% methanol (not at full meth pump duty). 700whp on a 70mm turbo.
zero knock and rich cyl 5&6. dont recall what timing is at. fairly aggressive though.

i could get 30psi daily im sure of it. but the dangers are too extreme for me.
 

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well i ran 37 psi on 93oct and meth injection on a little 67mm turbo and put down 830 at the wheels with an rb26, the main factors on how far you can go on pump is

1 a small turbo at high psi = hot air which in turn = easier knock
2 ofcourse intake air temps, your intercooler setup etc etc
3 your static compresion 8.5 will knock b4 8.0
4 this is just a theory i was given i dont have any info to back it up but i was told that aggresive cams help against knock something about the overlap blah blah etc etc
5 ambient temperatures also affect knock threshold
6 even your water temperature affects your knock threshold which makes sense because your head heats up the air also the contact surface of the cyl head, soo if your at 92 degrees celsius(stock thermostat) compared to 78 which is what the trd i think circulates at, essentially thats the temp your intake air is being submitted too

and then of course theirs timing
 

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Discussion Starter · #9 ·
Thanks for the information, i've taken in every detail.

I guess you guys have seen the recent thread for JamieP
http://www.supraforums.com/forum/sh...99rwhp-on-UK-pump-fuel.&p=8390984#post8390984

Mind boggling but i guess he has the odds in his favor.

AGM i would like to know whats stopping you from pushing it to 30 pound, i myself have a 76mm single with no stock internals. The head has 272 HKS cams in and out.

I WILL be running the meth without a doubt as i am not risking knock just because others can.

I know i cannot push 30 pound because the engine may very well make 1000hp which i don't want when running standard internals. My assumption is that your in the same boat and thats why you choose not to push past the power your making now.. or is there another dangerous factor i am unaware of.
 

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Lots of people in the Uk and the rest of Europe are running high boost on 98oct. Some even on 95!
It really depend on the tuner. Ryan G for example who also tuned Jamie P his Supra mapped a lot of high boost supras on pump fuel.

Go visit mkivsupra.net, 600+ rwhp on 67mm turbos or smaller all on pump fuel are pretty common.

Someone on this forum from the US is running pump with about 700+ rwhp, I think it is dregsx (rsp supra) or something like that.

Edit: the main reason for using pump fuel is that most countries over here can't get race fuel or higher than 98oct fuel.
 

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Here in the Philippines we have advertised 100 Octane RON pump fuel available at most gas stations especially in our capital of Metro Manila. It doesn't make that much power methinks compared to fuel in the US at lower boost levels.

BUT lately a couple of local Honda tuners have slowly started to push how much boost our local pump fuel can take. I've personally seen about 4 Hondas with B16 and B18 turbo set-ups and built engines running GT35 or similar turbos at boost levels of 22-26 psi on all but our 100 Octane pump fuel. 1-2 have even played with increasing timing once they hit 26 psi (they don't want to push it yet past 26 psi) and have made just under or over 600whp on a Dyna Pack dyno with of course other supporting mods like head works, wild cams, big valves, 10,000rpm redline-spec valvetrain parts and a huge intake plenum. Previously, the best they could get was high 400's to low 500's on lower boost levels (sub 20 psi).

Even they can't explain why or how, just that they keep pushing little by little on boost and ignition timing. I was also under the impression that sub 20-psi was the safe limit (and then some) but now for us, nobody knows yet how high you can push an engine on our local pump.
 

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i made 607atw with a little gt35r on a mustang dyno on pump at 31 psi with an rb25 with stock cams and an ebay manifold
 

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adammackintosh.net
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AGM i would like to know whats stopping you from pushing it to 30 pound, i myself have a 76mm single with no stock internals. The head has 272 HKS cams in and out.
the main reason im not running 30psi is because my tuner doesnt like it. hes worked on alot of engines over the years and has alot of experience and also very familiar with 2jz motors (this means nothing to you but he has only ever blown up 1 motor from tuning too far, and it was his own! theres alot of cars in my area being beaten on daily at 500hp and more tuned by him)
so obviously hes a bit on the conservative side having not blown up many motors. (i cant say the same for some other "really good" tuners)

i told him i want to reach 28 or 29 psi if we can do so safely. (thats why i have so much meth nozzle installed)
he said we probably shouldnt go that high (because its a daily driven car) but we ended up getting around 26 psi and settling at 24 psi with more aggressive timing around mid rpm.

whats an extra 40-50hp when your already running 700. i run street tires.... i wouldnt even notice an extra 5 lbs of boost.

you could consider having a 20-25psi map for daily driving, and a 'ragged edge' map for 30 psi or whatever and just run that for dyno days, and at the track.
 

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I found a huge difference between pump and E85, although i am from australia and we have 98 octane.
In saying that we were able to run a confortable 700-750hp on pump with no meth.
If your able to run E85 then i wouldnt even consider pump fuel.
I picked up 72rwkw (95hp) just swapping to E85 from pump and thats without more boost etc.
The temps were cooler, we had a much bigger window for error if needed and the power potential was also there.

Im sure none of this will help as your in a different country but for what its worth E85 is worth it weight in gold for the street.
 
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