Dan's Supra Project

[dandan]

Great stuff Dan,

 

Just reading the above, I didn't realise there was any performance gains had in connecting the catch tank to a vaccum source, unless I've totally misread

 

It's not something you hear discussed very often Jay but in certain motorsports you'll see competitors going to huge efforts to minimize oil vapours in the crankcase and drop the pressure as low as possible. Some will use vacuum pumps, or see the benefit from the scavenging effect of dry sump systems and of course there are options like the OEM PCV system or this "slash-cut" approach.

 

Hi Dan' date=' I used a Morroso system like this for a while (recommended by Dimmitri) but found it produced blue smoke from the exhaust on >7k overrun. Never measured the vacuum but decided to switch the slash cut feed to turbo inlet (used a much larger slashcut) and that seems to work well. I use a catchcan stuffed with wire wool to condense the oil, and see totally dry ic pipework.[/quote']

 

Hi Charlie - I remember when you set your system up and started running it. Did you run one slash cut or two in the exhaust and what size lines were you using? Over run is one situation where I don't have it 100% straight in my head what is likely to happen. Initially I couldn't imagine any meaningful vacuum but I'm now thinking it will be 100% the opposite. Only the gauge and MAP sensor logs will tell.

 

Edit: Did the elastomer in the anti backfire valves hold up ok or did it degrade over time?

Edited December 31, 2009 by dandan (see edit history)

[jevansio]

It's not something you hear discussed very often Jay but in certain motorsports you'll see competitors going to huge efforts to minimize oil vapours in the crankcase and drop the pressure as low as possible. Some will use vacuum pumps, or see the benefit from the scavenging effect of dry sump systems and of course there are options like the OEM PCV system or this "slash-cut" approach.

 

 

 

Hi Charlie - I remember when you set your system up and started running it. Did you run one slash cut or two in the exhaust and what size lines were you using? Over run is one situation where I don't have it 100% straight in my head what is likely to happen. Initially I couldn't imagine any meaningful vacuum but I'm now thinking it will be 100% the opposite. Only the gauge and MAP sensor logs will tell.

 

Edit: Did the elastomer in the anti backfire valves hold up ok or did it degrade over time?

Yeah, not something I'd heard, will do some reading on it, any online links would be appreciated

[paul mac]

What are your concerns about vacuum with this setup? Are you thinking there won't be enough at low revs and idle? My concerns are limiting the vacuum to sensible level but I'm sure I can get around that easy enough with a little experimentation.

 

my knowledge of crankcase vacuum is a bit sketchy but from what i have read the exhaust extraction type can provide a whopping amount of vacuum (which you seem to have under control) but at lower rpm where blow-by/ring sealing can be poor it really doesnt produce much vacuum at all, in effect the exhaust vacuum at high engine speeds performs like a super WOT intake breather, my concerns are the low speeds where you will not have the PCV to deal with excess gas - does this matter ? or is this low speed gas more of an emmisions issue

[b_have]

Hi Charlie - I remember when you set your system up and started running it. Did you run one slash cut or two in the exhaust and what size lines were you using? Over run is one situation where I don't have it 100% straight in my head what is likely to happen. Initially I couldn't imagine any meaningful vacuum but I'm now thinking it will be 100% the opposite. Only the gauge and MAP sensor logs will tell.

 

Edit: Did the elastomer in the anti backfire valves hold up ok or did it degrade over time?

 

Not sure what was happening on overrun, but I do get a lot of flameout, only used a single slashcut and located the antibackfire valve well upstream away from the heat.

Will look forward to your results

[Kirk]

this is new to me BUT am i right in saying your catch tank is being connected to the exhaust, for vaccum, rather than the intake?

[Homer]

Dan, it might be worthwhile PM'ing Digsy with a link to the last few posts in this thread. He is rather an expert in breather systems, I think he wrote a white paper on design considerations a couple of years back.

[dandan]

Yeah, not something I'd heard, will do some reading on it, any online links would be appreciated

 

I'll dig some links out mate

 

my knowledge of crankcase vacuum is a bit sketchy but from what i have read the exhaust extraction type can provide a whopping amount of vacuum (which you seem to have under control) but at lower rpm where blow-by/ring sealing can be poor it really doesnt produce much vacuum at all, in effect the exhaust vacuum at high engine speeds performs like a super WOT intake breather, my concerns are the low speeds where you will not have the PCV to deal with excess gas - does this matter ? or is this low speed gas more of an emmisions issue

 

One of my older NA cars ran a PCV to the intake and a single slash cut in the exhaust...both via a catch can. At the time I was just following other peoples' guidance so I don't have any real data from it but it worked well until the valve to the exhaust burnt out. I was only running a 3/8" pipe to the exhaust so it didn't have the vac potential of current system. I do have the option of adding an intake PCV back into this system if needed. That said, I am definitely getting vacuum at 900rpm; I can't tell you exactly how much but I should be able to get a gauge connected tomorrow.

 

The real question is why does anyone want or need vacuum in the crankcase? Based on the answers to that, the next question is when is it actually needed? Is it really necessary at all time including idle....that probably depends on why you think the vacuum needs to be in there at all. If it is to (slightly) help ring seal and reduce losses from spinning the crank through an oil mist then is that really necessary at idle? If the vacuum is part of the seal design on a particular engine then it would be sensible not to upset it and you'd definitely want to maintain it at all times.

 

It's been proven many times to free up power so I'm in for as much vacuum as is sensibly possible. All the digging around I've done has led me to want to stop at a figure of about -5psi to -6psi, hopefully sitting on the safe side of bearing oiling issues.

 

Not sure what was happening on overrun, but I do get a lot of flameout, only used a single slashcut and located the antibackfire valve well upstream away from the heat.

Will look forward to your results

 

Very nice My initial concerns were about the valves cooking (as I've had before) so mine are 4ft from the slash cut - fingers crossed. I'll keep you posted on the results, the over run scenario will be an interesting one to see some data for.

 

this is new to me BUT am i right in saying your catch tank is being connected to the exhaust, for vaccum, rather than the intake?

 

Spot on

 

Dan, it might be worthwhile PM'ing Digsy with a link to the last few posts in this thread. He is rather an expert in breather systems, I think he wrote a white paper on design considerations a couple of years back.

 

Cheers Homer. I remember him posting a few things up a while ago about OEM breathers and PCV systems but I think it was all low vacuum stuff and related to the function of the emissions/breather kit from the factory as opposed to vacuum pump/high vac designs. I will definitely give him a shout though and see if he has any new thoughts on these higher vacuum systems....especially in the sealing and little end bearing lubrication department. Thanks for posting up - much appreciated.

Edited December 31, 2009 by dandan (see edit history)

[b_have]

This was a mail I received from Dimitri many years ago:

Originally Posted by dk_supra

Best for the supra is 2 10AN lines from both cam covers to the front of the turbo where there is a lot of vacuum, or a crankcase evacuation system to the downpipe, for an extra 40rwhp. If you need more info, i can send details.

 

Regards

Dimitri

 

Might be worth giving him a mail?

[jevansio]

40rwhp for supplying a vacuum line to the catch tank?

[dandan]

This was a mail I received from Dimitri many years ago:

Originally Posted by dk_supra

Best for the supra is 2 10AN lines from both cam covers to the front of the turbo where there is a lot of vacuum, or a crankcase evacuation system to the downpipe, for an extra 40rwhp. If you need more info, i can send details.

 

Regards

Dimitri

 

Might be worth giving him a mail?

 

40rwhp for supplying a vacuum line to the catch tank?

 

Nice one Charlie, I could believe that on a very high horsepower motor. If I saw just 10hp on mine I'd be happy, it's all free power. I seem to remember Dimitri running into some lubrication issues from toooo much vacuum from the exhaust vac setup. I'll pm him again to ask.

Edited December 31, 2009 by dandan (see edit history)

[jevansio]

I think this is another one of those things I need to test for myself this year. I have been known to be wrong before, but IMHO Dimitri started losing my faith when he started backing 20" wheels as being great handling for the Supra

[dandan]

I think this is another one of those things I need to test for myself this year. I have been known to be wrong before, but IMHO Dimitri started losing my faith when he started backing 20" wheels as being great handling for the Supra

 

 

I'll be doing loads of testing Jay once I get the OEM MAP sensor back from Ryan and wired into one of my last 0-5V inputs. If the whole thing doesn't work as intended I'll do something else instead.

[paul mac]

 

I'll be doing loads of testing Jay once I get the OEM MAP sensor back from Ryan and wired into one of my last 0-5V inputs. If the whole thing doesn't work as intended I'll do something else instead.

 

great stuff Dan, real world testing is the definative answer and really looking forward to the results as this is something that has interested me for quiet a while

[dandan]

Everything is fitted now but the vacuum gauge I borrowed is goosed so no numbers yet. I can say one thing though - the whole system makes some strange noises. At idle it is silent; as the revs rise slightly it makes a strange quiet vibrating/deep whistle/pigeon-call kind of sound and the tank seems to amplify the noise. Depending on the revs and manifold vacuum/boost the noise is louder or quieter. It was actually a little bit un-nerving at first as I had no idea what the hell it was and it starts making the noise just above idle speed.

 

I really need to get the map sensor connected so I can evaluate what is going on in realtime and get some logs of system vac vs. rpm and engine load. I am wondering if the noise is from my lightly spring loaded vacuum limiting valve fluttering open to hold the vacuum in the tank around 1.5psi. Maybe.

 

So in summary - it's definitely pulling a vacuum (easy to feel through a sealable port on catch can) and definitely making some weird noises. However, I can't say anything more technical than that yet!

 

 

 

Edited January 2, 2010 by dandan (see edit history)

[Miguel]

Looking good. The check valve ports look low from the pictures; are you not worried about syphoning into the exhaust in the event of excessive oil getting in there? Or have you baffled the tank?

[Steve]

I have a spare stock MAP sensor if its any good to you Dan? Yours if you want it

[dandan]

Looking good. The check valve ports look low from the pictures; are you not worried about syphoning into the exhaust in the event of excessive oil getting in there? Or have you baffled the tank?

 

The tank is well baffled Mig - it would have to be filled almost to the top to get liquid across and up to the level of the check valve ports.

 

I have a spare stock MAP sensor if its any good to you Dan? Yours if you want it

 

Thank you Steve, that might be very useful indeed. I don't suppose you have the connector off the loom as well do you? Mine got chopped off when we fitted the 3 bar MAP sensor and Ryan (hopefully!) still has it with the old sensor.

[Steve]

Thank you Steve, that might be very useful indeed. I don't suppose you have the connector off the loom as well do you? Mine got chopped off when we fitted the 3 bar MAP sensor and Ryan (hopefully!) still has it with the old sensor.

 

I do if I can find a plug that will fit my current Denso 3.5bar sensor. I am waiting for some emails back from a few companies, hopefully they will respond next week now xmas is over.

[dandan]

Next I need to work out how and when I can fit this little lot. I still need the front top arms and rear strut rods but getting those shouldn't be a big deal.

 

 

Once these parts are all fitted it'll be up to see Mr Wilson to fit a set of his Bilstein dampers and custom springs.

[Callaway Motorsport]

Just read through your whole thread Dan,

 

I love it. great stuff your doing. alot of attention to detail and also more of the 'other' important stuff that can be done instead of just beefing up the engine.

 

Very good, and keep up the good work. Love the downpipe!!

 

Dane

[Homer]

My god Dan that is some money's worth of parts there! Very much looking forward to seeing the completed car (and hopefully a passenger ride in it)

[miko_supra]

Next I need to work out how and when I can fit this little lot. I still need the front top arms and rear strut rods but getting those shouldn't be a big deal.

 

http://i828.photobucket.com/albums/zz202/danc8000/Suspension/CIMG3606a.jpg

 

Once these parts are all fitted it'll be up to see Mr Wilson to fit a set of his Bilstein dampers and custom springs.

 

Ouch, bet that lot wasn't cheap. Those bolts alone cost around £15 each

[dandan]

Just read through your whole thread Dan,

 

I love it. great stuff your doing. alot of attention to detail and also more of the 'other' important stuff that can be done instead of just beefing up the engine.

 

Very good, and keep up the good work. Love the downpipe!!

 

Dane

 

 

Thank you Dane,

 

All the turbo related work and fabrication seems like an age ago now - in a way it would be nice to still be doing that as I really enjoy that kind of work. I have a few more modifications to do under the bonnet and then I will be happy with the car's engine/performance for Summer 2010:

 

Fit Greddy 3 row intercooler

Get the WI mapped properly

Confirm the vac/pressure characteristics of the breather system are as expected

Fit my new 4" centre section for the catback exhaust

Fit the electric exhaust cutout/dump

Install the sealed airbox

Get the traction control setup

Check the mapping and figures again on the rolling road

 

The only modification to come after that would be the Greddy intake but I think I will elave that until the winter as I need to move the battery etc etc and I want the car on the road and fighting fit for the summer.

[dandan]

My god Dan that is some money's worth of parts there! Very much looking forward to seeing the completed car (and hopefully a passenger ride in it)

 

Ouch, bet that lot wasn't cheap. Those bolts alone cost around £15 each

 

You're not wrong fellas ££££ and I still have front top arms, rear strut roads, more bolts and nuts, top mounts and insulators to buy. Then there's CW's kit and his time too

 

:faint:

 

However, these wet and cold roads only highlight the issues with overly stiff suspension on high powered cars. I can't wait to get this lot fitted along with a slightly specialized version of Chris' suspension and see how the whole package comes togtether.

 

No problem with anyone wanting a spin in it once the suspension is sorted. The bottom end grunt is just phenomenal and it is smoother and far more responsive than the TT setup. I can get well into positive boost at less than 1800rpm so the car is very easy to drive fast and there's almost no need for gearchanges when pootling around normally. The noise from the recirculating wastegate is also very stirring....coupled with that big K&N intake it sounds like a screaming banshee under the bonnet but without the booming and deafening drone of an open dump tube. The exhaust is damn near silent (for the time being) at anything other than idle so all these noises are that much more noticable.

Edited February 2, 2010 by dandan (see edit history)

[MarkR]

I can get well into positive boost at less than 1800rpm so the car is very easy to drive fast and there's almost no need for gearchanges when pootling around normally.

 

Fuel bill must be a little large?