Boost TVSV

[Draven]

Hi folks.

I'm just wondering if the behaviour of my car is a little odd.. So in third gear plant the fun pedal and it boosts quickly up to 7psi then doesn't move untill about 5k revs where it jumps up to 13psi right through to the redline and from 5k till redline it pulls like a freaking train.

I had removed the manual boost controller and plummed it back to standard TVSV. Wondering if the TVSV is getting stuck or something.

I will hopefully be getting an AVCR in april so i'm not that bothers if it is a TVSV thing.

Just a query really. Haven't had a Tubby for 4 or so years i just remember my old one on a Blitz ID used to boost straight up to 13 psi from 3k revs..

[mrfil13]

Thought you should hit full boost by about 3k.

[Draven]

Thought you should hit full boost by about 3k.

Yes that was my train of thought i seem to remember my old on used to.. hence my thinking the TVSV might be having a issue.

[raptor95GTS]

try lifting off to a closed throttle first while in third, then plant the pedal to the floor. Does the boost rise to max much quicker? This behaviour was the single biggest reason I changed to an MBC then EBC as the rev3+ VSV was a little too clever for my liking.

[Draven]

try lifting off to a closed throttle first while in third, then plant the pedal to the floor. Does the boost rise to max much quicker? This behaviour was the single biggest reason I changed to an MBC then EBC as the rev3+ VSV was a little too clever for my liking.

Hmmm it is quite funny and does seem to behave almost like you describe. some times depending on how i hit the boost it will spool right up to 13 psi..

I did figure that it was just the shitty VSV..


I'll defo be getting the EBC then..

[nickg07]

Getting my blitz sbc boost controller fitted tomorrow ill let you know what diff it makes. Rev 3 also.

[asdrewq]

Sounds like normal operation and as allan said - also the reason I got a MCB.

The only thing I did like was the 7psi limit on partial throttle, which made the car feel much more progressive in some situations such as balancing the power mid bend.

[paul port]

Knock Knock....

The Rev3 stock boost control is clever... It will hold off extra boost if it has experienced knock.

The biggest difference I found between 95 RON and 98 RON on my at the time Stock Rev3 (we are talking 12 years ago now) was the boost response pulling up the motorway slip from Windsor towards Maidenhead. On 95 RON, the boost would hesitate until just over 4K and then it would come in. 98 RON, smooth power and boost all the way.

This is when I fitted Water Injection, and found I got the same boost response from 95 RON as I did from 98. I ran WI 'till I sold it

The Rev3 T-VSV if locked on will raise boost to 20psi !! (Catalyst / exhaust flow limiting)
This gives the ECU a faster control loop - the Rev1/2 was just an on or off bleed.

If you are happy with the stock boost level, but are getting this hesitation 2k5 - 4k5 RPM I suggest you
- Clean up all your ignition components
- Check timing if there is any chance it has been changed in the past
- Gap your plugs
- Try an alternative fuel source

Paul

[Draven]

Hey paul

So

Had new sparkies (admittedly haven't been gapped properly don't have a feeler gap thing.. might need to check that)
New Disty
New Rotor
Luke @ pacific works checked my timing and adjusted it. did say it was retarded quite a lot when he checked.
New Fuel Filter


it is only run on 99 Tesco ron since i've owned it. I'll pop over to say shell and use some V-Power and see if there is any difference.

Only ignition stuff that hasn't been changed is the Leads and ignitor.. Unless i'm missing something.

I'm going to get a new cambelt put on when I can. Have the belt already just need to have enough cash for Luke to fit it.

Can't really think of anything else.

[Draven]

So just to check gapping spark plugs is simply

getting a feeler gauge and putting them together till i have 0.8 mm then simply using a pair of plyers to bend the tip of the spark plug till the feeler is difficult to put in??..

may sound like a dumb question but i've never gapped spark plugs before.. didn't know if there was some trick that i'm missing

Gonna nip to halfords after work and buy one. only 3.99 not sure why I didn't get one before.

[Slarty]

Usually the gap is too large on plugs, so I usually just tap the end down on a solid surface (work bench etc) lightly once or twice and check it again. Repeat until you've got a nice sliding fit with the 0.8 feeler.

You need to be careful if the gap is too small, bending the conductor can lead to the insulation (the white ceramic material) cracking to the conductor breaking off in operation. Personally if the gap is too small I'd just get a new set of plugs (£10 or so for a set of coppers?)

Also, from memory, don't ever try to re-gap platinums/iridiums as they're far more likely to break.

[Draven]

I bought

NGK BKR7E

they are standard coppers i believe.

[Slarty]

They're one range colder than standard (BKR6E) but yeah, they should be fine. There is usually another number on the end which dictates the pre-gapped size, I can only ever get hold of BKR7E11 (1.1mm gap) but it's no more than a minutes work to set the gap

BKR7E8 "should" be 0.8mm gap....I think!

[Draven]

http://www.opieoils.co.uk/pv-78241-ngk- ... tent=78241

Thats the link i bought them from can't find a number at the end.. But for the sake of £4 for a feeler gauge then i'll doubly make sure they are gapped correctly.. then its another thing off my list.

[Slarty]

Ah ok, in that case then it may be that no number at the end dictates that they're pre-gapped to 0.8mm but you're right, for the sake a £4 set of feelers and a minute or two of your time it's best to check.

[nickg07]

Set my s sbc and its great you. I tested stock without tvsv and i was getting 0.62peak . Set the gain to 25 and ratio to 45 or so and i hit my peak limit of 0.9 bar really quickly.

Just took my mum and my dad out in it so they could sample the new boost. my mum was clinging on for dear life so i didnt push too hard but the 1st gear and 2nd gear accel under full boost even at the level i set it at 0.87bar is shocking.

[Draven]

I just really want to make sure the car is running sweet before I get an EBC. If it is knocking and the standard TVSV is detecting that and limiting boost I want to fix the knocking first then get a EBC installed..

[nickg07]

How are you going to work that out?

[Draven]

How are you going to work that out?

Well that is a good question. I think i may have got it possibly as there was a leak in the coolant system which I have now fixed.

Going to clear any errors on the ECU then go for a blat see whether the boost comes in as well as it should do.. i've replaced pretty much everything else I can think of. Still need to gap the plugs correctly..

There is no reason why it should be knocking now really..

[nickg07]

If you are really unsure you could do what i planned to do.

Add ebc set it as standard or just below and take it to a reputable dyno where they can check the afr and knock so you can set utility up on the rollers...

I was booked in at awesomegti while a mates a6 is there for cambelt and remap but a week after id booked they called back to say actually there a golf r32 day on the same day so i can't go then.

Id definitely recommend the ebc and my blitz is great as it gives me real time boost display. Has a peak hold function so i can check afterwards what i hit at max.

Plus it has a stop limit so i can set an absolute max of say...1 bar and set it up so if i hit this then the screen goes red and it drops my boost back slightly.