Feck me! (Unexpected BPU)

[tbourner]

Why is this? I read this all the time but it makes absolutely no sense from a physics point of view. My car doesn't make any more boost in the winter and all I have is a restrictor ring... no boost controller.

 

My reason for thinking this....

 

The temperature doesn't have any direct bearing on the pressure seen at the manifold, well I cant' see why it would anyway. Boost controller works by tricking the actuator on the wastegate into thinking that there is less boost than there actually is. Stock boost of 0.7bar actuates the wastegate and controls the boost at this setting. The boost controller simply interupts this pressure and tricks the actuator, when the manifold reaches 1.2bar the boost controller (electronic) doesn't let the actuator see any boost until the manifold reaches 1.2bar and then it opens and closes to control the flow of boost (might not be accurate but that is how I understand it).

 

Now.... its very very cold. The pressure in the manifold is 1.2bar... what happens? The boost controller allows the wastegate to open and controls the boost at 1.2bar. Why would the temperature change that? What DOES happen in lower temps is the density of the charge changes... giving more oxygen to which more fuel can be added giving more power.

 

I'm not saying that in some or maybe even most cars there is a difference in the winter. I just can't see why it would make a difference, and it doesn't on mine

 

I thought boost controllers only increased boost beyond what it naturally wants to be. So with a boost controller 'set' to 1.2bar it can still boost up to anything it wants if the conditions are right?

[AlexM]

Ah ok fair enough, is it Jspec or UK? Assume if its overspooling it must be J-Spec.

 

It's the jspec facelift that I popped over to yours with just after buying it.

 

Besides, I know what an aerotop drives like on just standard TT, I can imagine it's a bit rubbish and very unsettling with BPU, but on a single... hm...

 

Just leave the roof on if you're going to play, it'll be fine.

[CJ]

I thought boost controllers only increased boost beyond what it naturally wants to be. So with a boost controller 'set' to 1.2bar it can still boost up to anything it wants if the conditions are right?

 

True. A BC can only up and not restrict or lower.

[T2 MSW]

It's the jspec facelift that I popped over to yours with just after buying it.

 

Mate I was head under a car than day getting annoyed with a started motor, All I know is it was shiney and Red

[deathmonkey]

Its worth just considering, I wish I had when I had to buy my FMIC again as the one for BPU was not up to the job.

 

I had an aerotop NA and with the roof on and a decent geo setup its was cool. Roof off is a whole new ball game

 

That's another thing - I'd like to keep the car as stock as possible - retaining the active spoiler. But an FMIC would see the end of that. I think I'd look into good SMIC options firstly. But if I really thought that single was a distinct possibility I'd bite the bullet and go FMIC. I'm sure I've seen good options on SMIC's for small singles...

 

Went for a good drive yesterday with the roof off, and it just reminded me how crap it is, compared to when the roof is on! I think BPU + roof off would just do my head in probably. I guess 19" alloys wont help in that respect . I've firmly decided that roof off = gentle cruising... roof on = when I do a bit more driving...!

 

Sorry for the thread hijack!!

[hoff]

When did you get a TT mate? I knew you were after one but did'nt know you'd gone and done it. Weldone dude:)

 

When you drove mine last year I had carried out BPU mods with a 1.2 RR but was only seeing a max 1.9 bar.

 

I have now fitted a HKS boost controller and set it to 1.2, which is what I am now seeing. However I still get spike of upto 1.36 bar. I would imagine this is because I need to get it set up a little differant.

[Class One]

Ah OK, no probs.

It's because boost controllers and gauges, tend to use gauge pressure rather than absolute, so they don't take into account changes to ambient.

 

Is that english?

 

Have a look at some of the threads Tony has started. You'll find them in the tech and projects section. (Yes there is a forum outside chat and off topic) He;s one of the most respected and technically able people on the forum and worth listening to. If you want to find out more about how these cars work, read his stuff.

[T2 MSW]

I thought boost controllers only increased boost beyond what it naturally wants to be. So with a boost controller 'set' to 1.2bar it can still boost up to anything it wants if the conditions are right?

 

Thats correct which is why a comon setup is to restirct the car to 1 bar with a RR (JSPEC) and use the boost controller to up to the required amount. That way you can tune out the variance with air temps through the boost controller settings either with a hi and low temps setting.

 

I never had to change mine though it just sat on low and never went above 1 bar. I still had the second cat in though.

[deathmonkey]

Have a look at some of the threads Tony has started. You'll find them in the tech and projects section. (Yes there is a forum outside chat and off topic) He;s one of the most respected and technically able people on the forum and worth listening to. If you want to find out more about how these cars work, read his stuff.

 

 

Never spoken to Tony or asked him a question, but I do find his posts answering a lot of my questions on a Supra when I do a quick search.

[T2 MSW]

That's another thing - I'd like to keep the car as stock as possible - retaining the active spoiler. But an FMIC would see the end of that. I think I'd look into good SMIC options firstly. But if I really thought that single was a distinct possibility I'd bite the bullet and go FMIC. I'm sure I've seen good options on SMIC's for small singles...

 

Went for a good drive yesterday with the roof off, and it just reminded me how crap it is, compared to when the roof is on! I think BPU + roof off would just do my head in probably. I guess 19" alloys wont help in that respect . I've firmly decided that roof off = gentle cruising... roof on = when I do a bit more driving...!

 

Sorry for the thread hijack!!

 

Im sure im in for a kicking from a mod shortly as this is well off topic. But yes your right a good quality SMIC can be good for small singles.

 

With regards to the FMIC some of the smaller ones can be fitted and leave the Active spoiler on all be it fixed in the down position.

[Matt H]

Thats a very sweeping statment Matt and I know for a fact there was more too it than that

 

No you don't Mike, I've never spoken to you about it. Your facts (whatever they may be) will be obtained from someone, who obtained them from someone else

 

Edit to say:

 

Anyway, that was 4 years ago now, so I don't want to get into an argument about it with you again now.

Edited January 19, 2010 by Matt H (see edit history)

[AlexM]

All I know is it was shiney and Red

 

It's Gunmetal(ish)! My old one was Red. Muppet.

 

That's another thing...

 

Chris Wilson does a well regarded SMIC, and Whifbitz have recently started doing one. Wez runs a CW SMIC on his single turbo track car.

 

I had to get rid of my Aero due to the ride with the roof off, it was great to drive on the nice smooth roads in Germany, but over here it was awful. It was a very nice ride with the roof on though.

 

When did you get a TT mate?

 

Whenever I sold the Aerotop, picked up the TT an hour or two later. I don't actually remember when that was.

 

I hope you mean a max of 0.9bar! I had to take mine to the SRR Dyno Day as I thought it was broken, performance was so dissapointing with 0.8/9 bar of boost. Hopefully BPU when setup properly will do the trick.

[deathmonkey]

Chris Wilson does a well regarded SMIC, and Whifbitz have recently started doing one. Wez runs a CW SMIC on his single turbo track car.

 

Yeah I've heard of both the CW and Whifbitz options.

 

Can anyone vouch for the quality of the Whifbitz SMIC, I'm sure it's good quality being a trader, but was just wondering.

 

Maybe an e-mail to CW is on the cards, a single set-up on one speaks for itself.

 

Cheers mate, and thanks to M5W as well.

[Matt H]

Not wanting to get into that at all, but on a side note;

 

Just wondering, I read that BPU is very reliable, but have there been a lot of problems on Supras when they initially go BPU then?

 

As long as your boost levels are not set too high then yes it is reliable

Edited January 19, 2010 by Matt H (see edit history)

[Sakey]

 

Whenever I sold the Aerotop, picked up the TT an hour or two later. I don't actually remember when that was.

 

 

Yep sold to me . Not sure when it was though, end of September sometime.

 

Alex don't go breaking your turbos! you only just got them!

[Scott]

I thought boost controllers only increased boost beyond what it naturally wants to be. So with a boost controller 'set' to 1.2bar it can still boost up to anything it wants if the conditions are right?

 

What conditions would cause a car to spike over 1.2 bar if it is the boost controller increasing the boost though? Say a car normally runs at 1bar for whatever reason, the boost controller then ups the boost to 1.2. Why would it go above 1.2 when it is cold? It wouldn't, hence my point.

 

Where did I mention decreasing the natural boost the car makes?

[tbourner]

What conditions would cause a car to spike over 1.2 bar if it is the boost controller increasing the boost though? Say a car normally runs at 1bar for whatever reason, the boost controller then ups the boost to 1.2. Why would it go above 1.2 when it is cold? It wouldn't, hence my point.

 

Where did I mention decreasing the natural boost the car makes?

 

Sorry, the way I read it was like the boost controller controls an actuator that comes into play and stops the boost from increasing any more.

To answer your question, you could be boosting to 1.15, add a BC to get it to 1.2 (for no real reason! ), then in cold weather it might go up to 1.3 or something.

[Homer]

What conditions would cause a car to spike over 1.2 bar if it is the boost controller increasing the boost though? Say a car normally runs at 1bar for whatever reason, the boost controller then ups the boost to 1.2. Why would it go above 1.2 when it is cold? It wouldn't, hence my point.

 

Where did I mention decreasing the natural boost the car makes?

 

That's not how it works, BC's don't exactly work on boost, they work on a set actuator adjustment level. When it gets colder this can vary. It's the same reason why you get a variation in peak boost on a car with a restrictior ring when the weather gets colder or warmer.

 

It was explained very well by Ian C (and others) in a thread last year in the tech section.

[T2 MSW]

No you don't Mike, I've never spoken to you about it. Your facts (whatever they may be) will be obtained from someone, who obtained them from someone else

 

Edit to say:

 

Anyway, that was 4 years ago now, so I don't want to get into an argument about it with you again now.

 

first hand from the person that was with you but anyway.

[Matt H]

first hand from the person that was with you but anyway.

 

As expected you're totally niave to what happened when my engine blew based on that. Nice use of the word fact Mike

[T2 MSW]

As expected you're totally niave to what happened when my engine blew based on that. Nice use of the word fact Mike

 

Matt we all know what happened from your threads at the time, you have your beliefs and then the rest of us know what happened

[Matt H]

Matt we all know what happened from your threads at the time, you have your beliefs and then the rest of us know what happened

 

You're such a clown. I quess the only person that has no stance on what happened is the guy driving, go back and read again... I'm sure it's possible for you to do that.......

Edited January 19, 2010 by Matt H (see edit history)

[T2 MSW]

You're such a clown

 

LOL, Matts answer to everything.

[Sharpie]

I did another test, hit 1.4bar

 

Please don't drive like this during winter or your car will end in the scrap yard.....we see it every year

[AlexM]

Please don't drive like this during winter or your car will end in the scrap yard.....we see it every year

 

I'm not sure what you're referring to here. 1.4bar on stock jspec turbos is obviously bad news at any time of the year, and is something I need to rectify. However I don't see that causing my car to end up in a scrap yard (it would be bad for my wallet though ).