Jump to content
The mkiv Supra Owners Club

Story so far with hub dyno results for BW 91/79


J_Boulton

Recommended Posts

  • Replies 100
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

Ok, I measured the stock tt head gasket and it's 1.4mm thick uncompressed. The bore size is 87.5mm

 

That would probably make it around 1.35mm compressed.

 

This means fitting a 1.2mm gasket would very slightly raise the cr.

 

Thanks Lee. Maybe my memory isn't as bad as I thought it was. :)

 

Just for reference:

 

1.35mm/87.5mm = 8.12cc ( 7.82cc if it's compressed to 1.3mm)

1.2mm/88mm = 7.3cc

 

I'm throwing my guess in with Adam's: the VVTi Cam timing. It can make a noticeable difference if not set up properly, specially with an aftermarket cam. Second guess would be the Turbo, but that's an easy test. Of course, I'm assuming that everything else has been ruled out.

Link to comment
Share on other sites

2 boost guages would indicate the problem but not fix it,cheap enough to do though .

Symptoms indicate some sort of control issue with the vvti not sensing an engine load demand - what does the system use to sense load ?

As you have had previous sensor issues are these all cleared, does the system read Speed signal for example as these seem to get corrupted with converters etc ,

if no fail codes shown it would be a false signal rather than a missing signal , such as a slipping speed pick up wheel or such.

Then is the system reacting to to correct signals?

If turbine or compressor knackered how do you make the power you have?

If bearings why no noise?

Link to comment
Share on other sites

To me the spool looks about normal compared to other 9179 plots I have, the shape looks about right....if anything, it's spooling well considering the other plots I have here are with 264 cams. (However, perhaps the vvti should be picking up the midrange a little better - hard to say with those cams).

 

For the sake of a comparison of the shape of the power curve......what do people normally use to bodge the TDI dyno figure up to a supposed flywheel figure? I have the TDI plot in excel compared to others at 9179 plots from SRR and can post it up once I scale the TDI values to something sensible....would an extra 12% be close to a SRR figure? That would make it a peak of 664bhp.

Link to comment
Share on other sites

To me the spool looks about normal compared to other 9179 plots I have, the shape looks about right....if anything, it's spooling well considering the other plots I have here are with 264 cams. (However, perhaps the vvti should be picking up the midrange a little better - hard to say with those cams).

 

For the sake of a comparison of the shape of the power curve......what do people normally use to bodge the TDI dyno figure up to a supposed flywheel figure? I have the TDI plot in excel compared to others at 9179 plots from SRR and can post it up once I scale the TDI values to something sensible....would an extra 12% be close to a SRR figure? That would make it a peak of 664bhp.

 

You cant compare a TDI plot in any way to a SRR plot as it loads the car up a lot more at TDI, the runs take 20 seconds, compare it to other TDI plots and you will see how laggy it is.

Link to comment
Share on other sites

  • 1 month later...

Right, latest attempt to try and get to the bottom of the lag is that the car is back with Chris having two HKS 264 cams installed.

 

At the same time Chris will be fitting new suspension (current setup has probably outlived it's usefulness), and a new RPS twin carbon clutch.

 

Oh, and he found a workaround to the missing locking wheel nut key - good old brute force, plus some fine fettling so no damage was caused. The Germans should have had a replacement sent out to me at the beginning of the week, after I'd supplied all the correct information, but their famous efficiency failed to materialise and nothing got sent. After a number of conversations they admitted fault and said a new one would be sent out immediately, but then proceeded to insist my postcode didn't even exist. It was at that point I reminded them who won the war. The new one should be with me tomorrow.

 

Chris began work today and has spoken to me a few times with updates, as there were a couple of issues that arose once he started dismantling things. One of them being the front main seal has failed and leaking oil so a new modified one is going in. The water pump is also on its last legs so that's getting replaced too.

 

And a rattle from the gearbox area when I switch off has been confirmed by Chris as the release bearing so that's also getting binned for a new one.

 

All those things aside, the main push towards eradicating the lag is the fitting of the new HKS cams and I'm very interested to see what effect they will have...

Link to comment
Share on other sites

  • 2 weeks later...

The cams have absolutely transformed the engine. Given it now really needs re mapping, and the wire to the VVTi control solenoid has now broken, after being "iffy", it is a different beast. It sounds different, revving cleanly and much more smoothly from idle, it now has usable mid range torque (although I personally think the turbo is still too big for a road car), and is generally a much nicer car to drive in every way. It seems to have an ongoing issue with the overrun fuel cut off being too aggressive and the fuel not resuming soon enough, which Julian is going to get looked at, and I am ordering a new connector and tails for the solenoid. If I say so myself it now also puts its power down 100% better and will take full throttle on damp, salty roads in third gear without frightening anyone, on R888's that are not at all a good tyre for -3 degrees. I am going to get the old cams on a Cam Doctor and see just what profiles they had.

Link to comment
Share on other sites

The cams have absolutely transformed the engine. Given it now really needs re mapping, and the wire to the VVTi control solenoid has now broken, after being "iffy", it is a different beast. It sounds different, revving cleanly and much more smoothly from idle, it now has usable mid range torque (although I personally think the turbo is still too big for a road car), and is generally a much nicer car to drive in every way. It seems to have an ongoing issue with the overrun fuel cut off being too aggressive and the fuel not resuming soon enough, which Julian is going to get looked at, and I am ordering a new connector and tails for the solenoid. If I say so myself it now also puts its power down 100% better and will take full throttle on damp, salty roads in third gear without frightening anyone, on R888's that are not at all a good tyre for -3 degrees. I am going to get the old cams on a Cam Doctor and see just what profiles they had.

 

Sounds promising Chris :thumbs:

 

What cams were taken out and which HKS were they replaced with?

Link to comment
Share on other sites

They do make a milder option, like Chris says just because they aren't working on Julians engine doesn't mean to say they wont work on another engine they are more suited to.

 

True, but I'm going for relatively large turbo combo, with the HKS Twins. I think I'd be highly f'd off if I didn't follow good research - maybe I'll go for the Titan 264's. I won't be ordering till early new year anyways, so gives me time to evaluate.

Link to comment
Share on other sites

Yep, the car is very different with the HKS cams in. As Chris says, it sounds much better too and something that I'm really pleased about is that the revs now rise and fall quickly again, sounding very nice, whereas with the Titan cams it revved like some little 1.2 thing, sloooow up and down, not nice. Bottom line is that it's now much more enjoyable to drive and is eager and ready to go from under 4k in third, rather than having to drop to 2nd and thrash it's nuts off to make any progress. Basically, it's a different car.

 

Next step is to fit the Precision 6765 that I've got and then get some niggles with the map sorted, including the ones Chris mentioned.

It's the DBB, billet wheel version and I'm hoping it'll give me earlier spool than I'm getting with the BW. If that turns out to be the case then I'll be very pleased.

 

Anyway, I'm so relieved that I'm starting to see light at the end of the seemingly endless tunnel and I'm really looking forward to getting it on the track in the new year as soon as the weather allows, particularly as I've now got a decent suspension setup. Also, once I've got everything on the mechanical side sorted I can finally turn my attention to long overdue cosmetic work, including the refurb of the BBS LM's, which I'm thinking of making all silver rather than the silver and gold they are now.

 

Chris, I've got the vvti solenoid connector working fine by using two very small spade connectors. As soon as I've identified which connector it is from the document yon gave me I'll let you know so it can be ordered.

Link to comment
Share on other sites

Yep, the car is very different with the HKS cams in. As Chris says, it sounds much better too and something that I'm really pleased about is that the revs now rise and fall quickly again, sounding very nice, whereas with the Titan cams it revved like some little 1.2 thing, sloooow up and down, not nice. Bottom line is that it's now much more enjoyable to drive and is eager and ready to go from under 4k in third, rather than having to drop to 2nd and thrash it's nuts off to make any progress. Basically, it's a different car.

 

Next step is to fit the Precision 6765 that I've got and then get some niggles with the map sorted, including the ones Chris mentioned.

It's the DBB, billet wheel version and I'm hoping it'll give me earlier spool than I'm getting with the BW. If that turns out to be the case then I'll be very pleased.

 

Anyway, I'm so relieved that I'm starting to see light at the end of the seemingly endless tunnel and I'm really looking forward to getting it on the track in the new year as soon as the weather allows, particularly as I've now got a decent suspension setup. Also, once I've got everything on the mechanical side sorted I can finally turn my attention to long overdue cosmetic work, including the refurb of the BBS LM's, which I'm thinking of making all silver rather than the silver and gold they are now.

 

Chris, I've got the vvti solenoid connector working fine by using two very small spade connectors. As soon as I've identified which connector it is from the document yon gave me I'll let you know so it can be ordered.

 

Why dont you get it mapped with the Borg Warner first, it sounds like its going to be a different beast altogether with these cams in it now. I've compared the 6765 with the Borg Warner and they were about the same apart from the Borg Warner producing slightly more torque.

Glad your getting there though anyway.

Link to comment
Share on other sites

I did suggest Julian gets the mapped tweaked to take account of the different cams, but it's his car, and I think he is keen to try another turbo. I think there is a need for more ignition advance off boost, but I am not a mapper, of course. If it were mine on a more user friendly mapping software I'd fiddle with it myself, but it's not, and I don't fiddle with maps on other people's turbo cars :) I would be curious though to see if Ryan could optimise things more for the HKS cams. Without tweaking the map I don't think a totally fair picture emerges.

 

Julian: Glad it's making dome progress at last. As I have always said, if it were mine it would have a smaller turbo, and more compression, but have a think about spending a bit more having the BW turbo map tweaked for the new cams. Let me have the part number for the VVTi connector shell and tails and I'll order them up straight away, together with the water temp gauge connector shell, and a few extra tails. Cheers.

Link to comment
Share on other sites

Good to hear that you finally came to a happy end. ;)

 

I would try and see what the BW turbo can bring after a proper remap ... see what can be taken out of it.

 

I personally have a GReddy intake plenum waiting to be installed, plus Water injection (50%water, 50% meth) and then have Ryan get his magic on the car ... remap to 1.8-1.9 is planned.

 

Cheers

 

Luc

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.