if you're able to apply pressure to the actuator have a look at how much pressure it takes to fully open the VNT, also check that it does fully open.
do you think you could have a leak in the pipe to the actuator?
Have you tie-wrapped the pipe to the actuator? mine leaked at a bar.
oh yeah, I think VW use a MAF sensor, which I think is where we started however many months ago...
Mr Cooke has!!Originally Posted by Os8472
wrong, as I said way back, you can't map out how much the VNT changes the VE of the engine with a MAP sensor.
anyway, another question for you, which side of the throttle does the actuator pipe go to?
Sorta tried that already and it seems to work, I tie wrapped a piece of wood to the underside of the throttle peddlebodge it and scarpper lol
The actuator is opening fully as far as I can tell.
I've replace the actutor hose twice and no change.
I always tie wrap vacuum hoses, I've seen what happens when they come loose.
The actuator pipe connects after the throttle body.
Call me stupid, whats the VE of an engine?
Really?
Great thread, I have been reading this from the start.Good to see more EFI C1J's being built.
Stick with it mate, you'll get there in the end I'm sure. It'll be worth all the stress, money and time.
sounds like you need a wastegate then. You wouldn't be the first to use one with a VNT.
Actuator pipe needs to be before the throttle, otherwise when you close the throttle the vanes will try and keep the boost up - ie you won't really be controlling the power with your foot.
VE - Volumetric Efficiency. ie how much air flows through the engine at a particular RPM
How has everyone else plumbed in a wastegate? did ya get a cutom manifold made up or is there some kinda adaptor that'll fit between the manifold and turbo?
Right I'll move the actuator pipe to before the throttle body, me being dumb didn't know you shouldn't have it after.
So what does VE actually mean then? is there a maximum air flow? how do you measure it?
Ha ha very funny
..........but true http://en.wikipedia.org/wiki/Volumetric_efficiencyHa ha very funny
Thanks Stu. Given you're trying to sort out EFI on the C1J, it wasn't hard eh Os.
it should really be a common sence thing for any engine builder, or tuner atleast! whoever mapped your car should know this stuff. if you have a variable restrictor (VNT) on the output of an engine (exhaust) then the ammount of air the engine consumes will vary accordingly. it all becomes a bit 3d. no longer is airflow connected only to manifold pressure and RPM but it's dependant on the the VNT too. since you need to match fuel with air then the afr is going to shift about as the vnt does it's thing.
now I've never mapped a car with VNT so I'm probably talking bollocks but I'd guess that I might be able to map the on-boost portion of map a bit rich to cover my arse, not ideal!
you're spot on there, and that's what I did. I'm hoping that it's better with the reduced overlap of my new cam. The problem is, it also means you have to be conservative with the timing too. The other thing I'm doing is mapping the VNT position, so that should mean that the vanes are always in the same position in the same part of the map - give or take any transients...
that sounds like an expensive mapping session on the rollers /dyno ?
Interesting read, still not sure on everything but then I'm no engineer lol...........but true http://en.wikipedia.org/wiki/Volumetric_efficiency
Oi, efi is the easy bit, getting it to work with a vnt is hard bit and before you say I'm not mapping it, I wouldn't have a clue, thats why I'm letting Dave do it.Thanks Stu. Given you're trying to sort out EFI on the C1J, it wasn't hard eh Os.
See thats interesting cus Dave had no problem getting the fueling to sit at exactly the afr he wanted, even when the boost shot up to silly amounts the fueling stayed spot on, when JP helped my rasie the rev limit he connected his LM-1 and watched the fueling and it never ran lean, even Dave hadn't finished the fueling map that far the ECU's factory defults were still in place which is to run abit rich which it did, it doesn't seem to have any problem fueling the VNT, just keeping the boost under control is the problem
How do you map the vane positions? scurb that how do you even tell where they are?
On the dyno things are static, it's when you get on and off the throttle that the fuelling goes silly. Maybe you won't see it, depending upon how fast your lamda reacts. I log this stuff and get to worry about it later. That said you won't have the overlap, or flow of my engine, so maybe it won't get so pissy about backpressure.
measuring and controlling stuff just costs time and money...
Fair play Os. The only thing I'd say is that you're asking for a lot of help from certain members in bottoming this boost/fuelling/VNT issue. I'm sure the guys are more than happy to help and the thread is really interesting for the rest of us. In return for the assitance you're getting however, you'd have thought you'd at least be using Google where possible (i.e. to help you understand physics/mechanics basics), instead of adding the extra load to Andy (or whoever).
Might be worth looking at other turbo options instead of the vnt? Plenty of good blowers out there. Is it really worth all the hassle of trying to set it up, i.e mapping costs, parts & time wasted etc.
Bob on Brigsy
If it were that much aggro (and let's be honest, everyone who's tried fitting a vnt to a gtt before has had said aggro in plentiful supply), wouldn't it make more sense to just fit a conventional blower & be done with it?
The efi setup in itself surely outweighs any disadvantage of a 'slower' spooling conventional turbo being in situ?
I have tried mate but as I said before I'm no engineer and understanding stuff like that is abit beyond me, yeah I can bolt stuff together no probs but get to the technical stuff and i'm lost, now if it was women I wouldn't have any probs in making scream with pleasure in less than a minute
True but just because somit is hard doesn't mean you shouldn't do it, if we did try we'd still be leaving in cavesBob on Brigsy
If it were that much aggro (and let's be honest, everyone who's tried fitting a vnt to a gtt before has had said aggro in plentiful supply), wouldn't it make more sense to just fit a conventional blower & be done with it?
The efi setup in itself surely outweighs any disadvantage of a 'slower' spooling conventional turbo being in situ?
Aii, and I'm all for development ideas, but in fairness you've been dicking around for months trying to resolve this, and surely there comes a point where it just ain't gonna happen.
When I see someone like Andy struggling to get a variable unit working sufficiently good enough, and bearing in mind the application for his car/turbo is hill-climbs, where yours is more road-usage & hence more 'necessary' to set up correctly, I think the caves you mention would be pretty desolate by now...
I haven't been dicking around with this for months, I've only had the problems with boost since the last dyno seesion which was on the 24th of november but I've been busy trying to trace this oil leak since then, I have been dicking around with other issues such as the oil leak and slipping clutch but those can happen on any car
My bad. I must be getting confused between that and the efi install itself.
Fair play for seeing it through; it'll be a good conversion when it's all tickity boo
No worries dudeMy bad. I must be getting confused between that and the efi install itself.
Fair play for seeing it through; it'll be a good conversion when it's all tickity boo
Sigh. You didn't try in this instance and in any case if Wiki can't help you understand it, how is Andy supposed to do any better. More pertinently, if it's beyond you, why are you asking. Forget it I'm out, but good luck with resolving the issues.
When I see technical stuff writen down it tends to blur, where as if some explains in simple terms I can sometimes understands whats being said, I am dislexic ya know (can't even spell it lol)Sigh. You didn't try in this instance and in any case if Wiki can't help you understand it, how is Andy supposed to do any better. More pertinently, if it's beyond you, why are you asking. Forget it I'm out, but good luck with resolving the issues.
cool, well its good that it maps up OK, that would have been my only worry really.
re your boost control, how did you get on with running the actuator before the throttle ? it can do some wierd stuff at part throttle when you have it conencted to the manifold. there's nothing simpler than going straight to the compressor housing with the pipe.
if it's still going mad after that then I guess its down to adjustment of the vanes or the actual sizing of turbine ? can you get a too-small a vnt that is un-able to open up enough to keep the boost within limits ? as I say, I know fudge all about vnt, I'm just applying some logic
id love to see Alan at AVA's face if i turned up there with a vnt strapped to mine and asked him to map itnot cause i doubt his ability to be able to do it more of the case would be why????
as others have said is it really worth the extra hastle , i can see why andy is spending time trying to get the best out of using a vnt as he will only use the car for hill climbs, but for a road car and the power im guessing your aiming for all it will do for u is light up the front tyres @2k rpm instead of at 4k and probably make your power band shorter ,although i have no idea what size of turbo your using .
Ive been toying with the idea of going for a bigger turbo but i think for the way i like to drive and the roads i mostly drive on the t25 seems to be ideal and a good compromise ,and sticking with what i set out to have my 5 like a bit of an all rounder not losing track by chasing those magical bhp figures .
ditch the vnt m8
Got a poster of this car on my wall and was great to see it in the flesh at nationals day.Keep up the good work.Great modifications and i like how it looks almost factory with the phase1 front bumper and decals.
Yeah I was worried about how the mapping would go, after hearing so many people say ya couldn't have a EFI and a VNT I thought I was pushing my luck but if the only problem I'm having boost control it could be alot worse.cool, well its good that it maps up OK, that would have been my only worry really.
re your boost control, how did you get on with running the actuator before the throttle ? it can do some wierd stuff at part throttle when you have it conencted to the manifold. there's nothing simpler than going straight to the compressor housing with the pipe.
if it's still going mad after that then I guess its down to adjustment of the vanes or the actual sizing of turbine ? can you get a too-small a vnt that is un-able to open up enough to keep the boost within limits ? as I say, I know fudge all about vnt, I'm just applying some logic
Annoyingly there's no tap off the compressor housing to connect the actuator hose, so I'm gunna tap it into the first boost pipe after the turbo, hopefully that'll make even a little bit of a difference.
Honestly if I did this again with another R5 I wouldn't use a VNT but since I've already started with this 1 I intend to see it through, yeah life would be alot simpler with a T25 but I like to at least try get stuff workingid love to see Alan at AVA's face if i turned up there with a vnt strapped to mine and asked him to map it
as others have said is it really worth the extra hastle , i can see why andy is spending time trying to get the best out of using a vnt as he will only use the car for hill climbs, but for a road car and the power im guessing your aiming for all it will do for u is light up the front tyres @2k rpm instead of at 4k and probably make your power band shorter ,although i have no idea what size of turbo your using .
Ive been toying with the idea of going for a bigger turbo but i think for the way i like to drive and the roads i mostly drive on the t25 seems to be ideal and a good compromise ,and sticking with what i set out to have my 5 like a bit of an all rounder not losing track by chasing those magical bhp figures .
ditch the vnt m8
Cheers bud, never thought my car would be a pin up lol, when it went for paint the 1 thing I said was "I went to keep it factory looking but with a modern twist"
Oli, if you want a proper threaded insert for the compressor housing, i'll send you one. If there isn't a blanking plug you'll need to tap and drill the comp housing though, which is nearly impossible to **** up.
I'll be able to f**k that up
thats ok mate, I've got naff all time at the mo anyway
I do love it when I'm proved right, when my 5 was in carrera gettin paint I had a 200sx as winter beater, when I sold it, it was a non runner so I took a few bits off before hand 1 of them being the turbo and it has a take off in the compressor housing, now if I'd listerned to me old dear I woulda got rid of that months, glad I didn't now.
After 20mins in a soaking wet, muddy scrap yard I have a throttle body I think will help, the 1 I originally used was off a Mitsibushi Starion and it was 55mm internal dia, now I have a 40mm internal dia job off a ford fiesta, all it needs is a hole blanking, an old bracket removed and my TPS sensor fitted and calibrated, I'll you guys know how I get on.
I don't see the point in fitting a smaller throttle body if your wanting power. Might aswell go back to the old 25mm carb eh..
just chuck the carb back on... worked ok for stu clarke
The standard is 25mm, I fitted a 55mm for the conversion, now dropping down to a 40mm, should still give a power increase over the carb and far better mpg
Shut it Butterworthjust chuck the carb back on... worked ok for stu clarke
....you know i'd have your setup, just for the noise on the limiter! lol
If ya out 2nite mate I'll take you out in it again, now the rev limiter is up you believe what its like, when it hits the limiter at 5500rpm it pops even bigger flames
your on
New poster! (less than 10 posts)
throttle size has nothing to do with fuel ecconomy ?? it also won't make any difference to your boost control problem unless you go so small that it becomes a choke. the only advantage of a smaller throttle will be that its responce will be a little more progressive, it won't be quite so sensitive as I bet it is now at 55mm.
I was never sure having the 55mm was a good idea at the start of the conversion, and yes your right Scoff, the slightest throttle launches me down the road with smoke poaring off the tyres or I stall it and look a cock
id say the going down the road with smoke pouring off makes you look like more of a cock than stalling it
Yep I'll give u that
TBH We all think you look like a cock all the time
TBH We all think you look like a cock all the time
I can't help it if I'm so well blesed that all you see is my cockTBH We all think you look like a cock all the time
no he out right called you a cock, didnt mention seeing your weenerI can't help it if I'm so well blesed that all you see is my cock
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