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Does BPU bring any real performance gain?


Alex_GT

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Running at 1.1-1.2 bar transforms the car imo. But be prepared to replace the coil pack connectors and possibly even the coilpacks if they are originals. That bit of extra load shows the otherwise unnoticeable breakdown of these components. Also be prepared for other weak spots to come to the surface, think it was Jasonr24 on here who recently went bpu and it pushed a turbo over the edge. But yes its great.

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The problem is I don't want to damage anything if the risk isn't worth it, is there any way of checking if the car would be vulnerable to failure, paticularly turbochargers?

 

Bit of a daft question isnt it? "Does 100+bhp make your car faster"?

 

Yep :thumbs:

 

100hp? I thought BPU was only good for around 50 extra horsepower? At 1.1/1.2 bar?

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With BPU and a FMIC my '96 TT6 made 420 at 1.2 bar on the rolling road at a TVR vs Supra shootout at the place near Gatwick (the name escapes me). I reckon with a decent SMIC, like a CW one, it would make about the same.

It was an absolute animal (not as much as the big singles but a handful none the less) and it really would play with the big boys and would quite happily spin the rear wheels in 4th it you gave it a boot-ful. I had it like that for about 7 years until my wife stacked it. But nothing really went wrong with it as I stayed on top of the services and replaced things like the coil pack connectors.

 

It's a totally different car once BPU. But as others have said, if you're not prepared to deal with stress causing issues then don't push it too much.

 

Has it done a load of miles?

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I run full BPU (FMIC, 1.2 bar, both decats, colder grade spark plugs, etc etc) and anyone who knows me knows I drive the car very 'spirited' and I can say I have had no issues whatsoever with reliability.

Since being BPU the car has been around Scotland, up and down to England a few times, Over to Europe and will soon be doing its first track day.

You will definitely notice a difference and I feel the second turbo comes on a lot more savage with the extra power.

I also upgraded all the turbo pipes and rad etc when I went BPU as a lot of the parts are now 22+ years old and maintenance isn't a dirty word ;)

 

Do it, you won't regret it if you are feeling your stock power output is slow.

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These are old cars and of course making a pensioner run a mini marathon comes with risks. Have a full engine and oil service and a leak down test performed first, and fit a mechanical oil pressure gauge and a mechanical boost gauge so you can monitor the vitals. "Speed costs money, how fast can *YOU* afford to go?" was the plaque above the door at an engine tuner friend of mine's for many a year. A mangled piston and con rod hung beneath it....

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Running at 1.1-1.2 bar transforms the car imo. But be prepared to replace the coil pack connectors and possibly even the coilpacks if they are originals. That bit of extra load shows the otherwise unnoticeable breakdown of these components. Also be prepared for other weak spots to come to the surface, think it was Jasonr24 on here who recently went bpu and it pushed a turbo over the edge. But yes its great.

 

Yea that was me. To be honest before going BPU I'd make sure the car is in tip top form to take the extra power even parts you may not even realise, for example there's a few hoses down the back of the engine, one is a vacuum feed for the second turbo to allow it to come online, mine had perished and split so I didn't have a second turbo the whole time I'd had the car. So definitely worth checking. Not to mention plugs, fuel filter etc.

 

Then even after making sure the car was tip top, there's no telling at all when the stock turbos will go. I had the car 24 hours once it was all sorted. Running at 1.2 bar and the first turbo just let go. heard bits of it rattle out the exhaust!

 

It's definitely worth doing but as above I'd get a decat and bigger exhaust first just to get a feel for it and see if any gremlins rear their head. Nothing worse than going full BPU straight away and having to get the turbos rebuilt ;)

Edited by JasonR24 (see edit history)
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Mine is full bpu , i see the figures being quoted and accept different dynos give different results , mine achieved 354 bhp at the wheels and 350lbft torque , on two different dynos, so why so many achieving 400 bhp at the wheels! In answer to the question yes makes a great difference.

Mine is a 97 tt vvti tiptronic auto.

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Mine is full bpu , i see the figures being quoted and accept different dynos give different results , mine achieved 354 bhp at the wheels and 350lbft torque , on two different dynos, so why so many achieving 400 bhp at the wheels! In answer to the question yes makes a great difference.

Mine is a 97 tt vvti tiptronic auto.

 

Take it to the track. Mph doesn't lie :)

A proper bpu spec runs +/- 120mph in the quarter, which is around 400whp depending the dyno you use. Mph might be a little lower 116-118mph using 98ron fuel.

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Mine is full bpu , i see the figures being quoted and accept different dynos give different results , mine achieved 354 bhp at the wheels and 350lbft torque , on two different dynos, so why so many achieving 400 bhp at the wheels! In answer to the question yes makes a great difference.

Mine is a 97 tt vvti tiptronic auto.

 

Mine was 319.7 at the wheels, 418.2 at the FW and 352.1 torque somewhere or another.

I just thought it was generally accepted to give the biggest figure in everything in life ;) - "well it was that length at some point so that's the figure I'll quote".

 

Also, wasn't the stock 280 / 320bhp at the FW?

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Performance difference is huge when you bpu the car, you'll be pleasantly surprised if it's speed you're after. Personally i prefer the drive of a catted supra though, mine feels more responsive throttle wise.

 

I have two at present (one completely stock) so can drive them back to back and initially I was not that impressed by the bpu below 2nd turbo range (not sure it's worse (it was on mine due to a boost control issue) but no better), I have since done the first turbo mod to slightly up the boost and it feels much better from the bum dyno/responsiveness. The removal of the boost controller has meant the max boost is only 1 bar at present I need to open out my restrictor ring a smidge.

 

Take it to the track. Mph doesn't lie :)

A proper bpu spec runs +/- 120mph in the quarter, which is around 400whp depending the dyno you use. Mph might be a little lower 116-118mph using 98ron fuel.

 

Flat out ie always in the 2nd turbo zone and yes you are right it's always pulling much harder than the stock one.

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Mine was 319.7 at the wheels, 418.2 at the FW and 352.1 torque somewhere or another.

I just thought it was generally accepted to give the biggest figure in everything in life ;) - "well it was that length at some point so that's the figure I'll quote".

 

Also, wasn't the stock 280 / 320bhp at the FW?

 

How can you loose 100bhp from the flywheel to wheels? Doesnt sound like an accurate dyno.

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