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The mkiv Supra Owners Club

BPU with Jap/UK Cars


Magsy

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Just about to start seriously looking at Supras but I have a question.

 

Over on supraforums etc (anything us based) they are all claiming (well, lots of dyno graphs too) 400-450 RW BHP from just doing BPU.

 

So thats a BCC, Downpipe/Decat, exhaust and a boost controller.

 

There aren't that many people worrying about fueling / blowups or have blown up at this level.

 

The thing is, reading on this forum, i get a very different impression. Fueling seems to be a point raised a lot and there are also a lot of knackered engine stories.

 

On top of that not many seem to be claiming such great RW BHP from these mods.

 

So my question really is, what gives here? Does the US car differ from ours/jap ? (I thought it was pretty much a jap one?)

Why do our cars make less power for the same mods? (or so it seems, I haven't seen many dyno graphs here)

 

Ian

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Why do our cars make less power for the same mods?

 

Biggest reason here is they use SAE corrected power figures and we use DIN corrected. Just a slight different factor used in the calculation.

 

Rolling road figures also change with tyre pressures, tyre sizes and transmission types.

 

I've never known how they get such quick 1/4 mile times compared to us.

 

Regards

Pete

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Forgot to mention the 1/4 times in first post, yes they seem to be way ahead there too :(

 

According to a quick google, the SAE to DIN conversion would make 450hp into 455hp, so we should have more - the conversion factor is so small it makes hardly any difference.

 

Cheers

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US car is most similar to the UK car, JDM car is different in a few ways. What it really comes down to is the yanks seem to take more risks (they can afford to, things are cheaper there) and are inherently spewing more BS. :D

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Originally posted by ThunDeR

US car is most similar to the UK car, JDM car is different in a few ways. What it really comes down to is the yanks seem to take more risks (they can afford to, things are cheaper there) and are inherently spewing more BS. :D

 

Errr...perhaps

 

But a quarter mile is a quarter mile...

 

:)

 

And not even Geoge Bush can BS THAT

 

...well...maybe...well...definately...and oh dear!

 

:p

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Yer I'll give em that Paul, but they do have a distinct advantage - drag radials (cheap) and cheap high octane fuel (much higher than ours) really makes it a wee bit unfair on us :(

 

The fuel being better quality / octane is why they can get away with taking more risk and don't have to worry about fuelling so much.

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Roughly speaking their RWHP figures equal our CRANK HP figures, and as already stated drag radials and race fuel are MUCH cheaper and readily available over there. Their drag strips are also properly prepped too being a much more popular sport over there. If you've ever been to the Pod when the big dragsters are on they put this sticky stuff down on the track and your feet actually stick to the track a bit when you walk over it.

 

BPU cars here have got into the 12's (still working on that myself!) but with drag radials I would think knocking a second off that time would be certainly possible. I know they run in the 11's.

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Thanks for the welcome, very nice forum here! Couldn't find a uk supra forum at first but I stumbled upon it in the end! :) :)

 

The power could well be iffy but paulrenn's point gives a good understanding of the 1/4 times, thats 350metres shorter than ours, prob not very much at 100mph+ but still make a resonable difference. Anyone care to guess how much?

 

I thought US had crap fuel? 91 oct standard and 95 oct as their 'super'? or do they have readily available 100+? (bastards:))

 

Thanks all

 

Ian

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They can get all fuel cheaper than us and they have more places to get it.

 

The Yanks rate their fuel by MON and we use RON.

 

Their BHP is bull IMO.

 

But the times are down to

100+ octane fuel

Drag Radials

Cleaner dragstrips - better tarmac - much more investment

And having the UK car's spec (sans bonnet vent) to start with inc. 550cc injectors - the fuelling needed by J-specs to run hybrids.

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Lol. tbh i don't know the imperial system at all, i know their gallon differs but i didnt check miles :p

 

good link here on ron v mon http://www.btinternet.com/~madmole/Reference/RONMONPON.html

 

Their 95 MON is equal to 105 RON!!!

 

:devil:

 

Define 'hybrids' for me please, what does it refer to exactly?

 

Can you buy the 550cc injectors from toyota? or elsewhere? £?(cheaper than a proper setup - if only going for a resonable power increase)

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Magsy,

 

You did well with the search button and the RON/MON....no go forth young Jedi and try it on Hybrids and 550cc injectors :)

 

In the Resources -> Technical Referance section on this site there is a guide on switching to 550cc injectors on a JDM Supra

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116 MON leaded race fuel is not uncommon (that's about 124 octane by our figures I think). That's why they don't bother too much with new ECU's when putting big turbos on (cos the engine won't det on that octane even with the standard timing map) and why they put so much power down. It's also worth considering that they pack the intercooler with ice/CO2 during dyno runs, turn the boost up to crazy high levels (and then turn it straight down again when they drive off the dyno), basically pull any tricks they can to get a high rwhp number. All total bollocks, people over here dyno the cars exactly as they run on the street with no special tricks. Those things considered (along with those already mentioned) make a huge difference.

 

There are some SERIOUSLY quick cars in the states though, some 1/4 mile specials, but some that are properly built and should hang together.

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