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Gtir Motorsport club » General Discusion » Gtir related Discussion » Power problem

Power problem

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26 Re: Power problem on 13th February 2017, 9:52 pm

PartyPete

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the one star club
the one star club
After the cams were dialled in it made more torque but literally no more power at all! That's when he said he was thinking the intercooler may be an issue due to the size of it.....

27 Re: Power problem on 13th February 2017, 10:02 pm

johnny gtir

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This is what annoys me. I know you can not expect the world the car should be right as it's mapping not repairs etc. But if it's not stuff like pipes blowing off or similar. There the so called experts that's what you pay for mapping so if it don't make power surly they should know why/what is restricting it and how. You heard my major let down and bull shit I was fed last mapping session.  I went to bob Only reason I did not in first place was the extra distance he got over 400 bhp and took the time to pre check stuff explain what he was doing and the car map wise was faultless I got a boost leak on a split pipe (certainly not his fault) car went to Germany and back once back I found the leak split pipe.

28 Re: Power problem on 13th February 2017, 10:16 pm

PartyPete

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the one star club
the one star club
I didn't hear no? After it had the map and didn't make the power I was fetching the car back any way as I wanted it back/couldn't afford to have any more diagnostic work done etc. So that was kind of it for the time being, and now I'm back on the hunt to find the problem

29 Re: Power problem on 14th February 2017, 11:23 am

ducie54

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Remember pressure is a restriction of flow. Just because your running 2 bar boost does not mean you have the air volume for a specific HP. Your boost is falling off meaning there is a flow issue. Weather it be a restriction in the intercooler, turbine back pressure or just the turbo not flowing enough.

If it was mine I would do the following before I visited the dyno again. Cap your exhaust pipe and pressurize the intake and check for leaks. Fit a better quality intercooler, weld a nipple onto the turbo manifold ( means turbo off again tho), find a second hand MSD 6a ignition module and a blaster coil. (This removes the unreliable factory transistor). Don't mix and match aftermarket ignition components like MSD or crane.

30 Re: Power problem on 14th February 2017, 2:28 pm

Mr B

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gtir technician
gtir technician
Would expect to see more pressure loss and less cooling efficiency when cooler failing to flow air volume available, testing ideally wants logging so see map  of the pre and post pressure differences in relation to rpm in a full throttle run right up to red line.
If you got time and curious I would add thread take offs at turbo outlet and just before plenum entry to get full evaluation on intake run. doing pre & post turbine pressures super useful too and if size the thread take offs right they can all double as temp probe points which all could be handy data at some point .
I have had 4.5psi+ pressure difference spikes on 2.5" thick 12" high cores and still managed almost 440hp .
What is size of you core, amount of rows is just as important as depth for flow potential .
You can work out you core flow area: depth of core X row width X number of rows .
Core is reasonably cheap option and if current one not great quality it not bad area improve as better flow and cooling efficiency going net you easy safe power for the trouble just maybe not as much if it not the main problem :-) .
would deffo look at turbine pressures though, how your wastegate/manifold/exhaust configured and how the exhaust pipe shaped/sized directly after turbo as design here plays a big roll .
I not had much issue with factory ignition or  power transistor at under 1.8bar, I relocate the power transistor to cooler location and a heat soak alloy bracket plus keep a good spare handy .
Is good advice upgrade though as saves potential for problems and far safer to almost a must do when at or over 1.8 bar boost .

31 Re: Power problem on 14th February 2017, 7:56 pm

johnny gtir

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He runs the forge core they listed for the pulsar

http://www.gtir-motorsport-club.com/t7104-forge-front-mount

32 Re: Power problem on 15th February 2017, 12:38 am

ADSgtir


Seems to me your boost is dropping from 4500 rpm onwards ,ending at about 1.65bar , this is dropping the volume of air and the torque is dropping faster than it should (with constant boost)
you only need about 32 ft lb more at 6500 and there is your 450 hp.
You say that increasing the boost makes no more power , probably just increasing the leak rate of wherever the air leak is .
the boost controller should maintain a constant boost .
There could easily be 50 horse leaking out of a coupling

33 Re: Power problem on 15th February 2017, 7:31 am

PartyPete

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the one star club
the one star club
Surely if I was getting a leak under boost it wouldn't run properly I.e miss under boost?? I've taken note of what people have said so far and I will only have time to do a few things before it goes for mapping. I'm changing the intercooler but from what mr b says it may not be the issue?

34 Re: Power problem on 15th February 2017, 9:11 am

Mr B

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gtir technician
gtir technician
^ hard say without tests, I will say those forge coolers are well over rated/priced and actual piping kit from forge was a fooking disgrace and not what would expect for huge cost or a so called motorsport fabrication/engineering company.
From rough guide chart I use you would need a core area of over 35in^2 for around 470hp, real world testing shows can use smaller than ideal and get fair results, but better you match the cooler to turbo better it works in all respects.
Educated guess tells me cooler not ideal for final power goal but should handle more than your current hp, I would be checking pressure drops right across intake just be sure it all normal then move on to turbine exhaust and boost control.
I would assume it likely your dead turbo bearing a fatigue result of issue you got in current system.
When boosting at likes of 1.8bar leaks can be sneaky and seal themselves fine at lower pressure and vacuum, would not be a surprise if 2 tuners overlook/miss that though as most in uk are fooking useless.
It really is a case of test everything and assume nothing, guesses can cost a lot of money but should be used as direction on where look for visual clues and collect data values.
lot of tests you can do yourself as you a hands on guy and done some already,
Intercooler wouldn't be overly costly upgrade and can reclaim some cost selling the current forge but rolling road sessions when not getting technical answers or hp are costly and waste of time.  
You got any good shots of all intake pipe runs and exhaust/exhaust manifold/wastegate so can visually see your setup ...

35 Re: Power problem on 15th February 2017, 10:01 am

PartyPete

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the one star club
the one star club
I'm thinking the next logical step will be to do a boost leak test to be on the safe side then? I made all new boost pipes out of ali and there's only a few small rubber connections....but would be good to rule this out! I can take some pictures later of my set up to show you. There's no nasty sharp restrictive bends anywhere either on the air intake to turbo, the exhaust or the boost pipes, I've made sure of that! It's a standard manifold but ported. It's has electronic boost controller, think it's a profec spec 2 if I remember correctly? The turbo has just been fully rebuilt and fitted with a large exhaust wheel

36 Re: Power problem on 15th February 2017, 2:00 pm

johnny gtir

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moderator
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Two very good points from above boost controller not holding it and the gate. Oh and a 3rd fucking mappers in U.K. Seem very lazy compaired to other places. I agree when people blame them in not there fault but most The fookers would rather sell you something new then spend the time to help find a problem.
I said it before and I will say it again reason bob was priceless on my car checked above and beyond before it even went on the rollers. Nothing was to much hassle and the car won't leave until he is happy with the results and your happy more to the point

37 Re: Power problem on 15th February 2017, 3:24 pm

mike74

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I'd agree that doing a boost leak test at 2bar would be a very good shout and worth checking before anything else IMO

38 Re: Power problem on 15th February 2017, 3:55 pm

ADSgtir


On the bright side a leak is the cheapest possible repair !
Finding them is the issue , they can be most awkward and well hidden , injector seals, wastegate cracks ,intake manifold gaskets , split pipes , cracked intercoolers and so on .
Pipes without sealing humps is a favourite place , leaking from couplers .
Whatever you must have constant boost pressure to map against (unless you have in gear boost control) , now it may be mapped against a leak - the last mapper should have seen dropping boost on the graph , that is the point in measuring it isn't it ?

39 Re: Power problem on 15th February 2017, 5:32 pm

PartyPete

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the one star club
the one star club
I've bought a new exhaust housing for the turbo as the old one had a couple of pretty severe cracks in it around the waste gate and further inside, not sure how long they had been there for though! I need to do a boost test with a kit I can add some dye to so that if there is one I would be able to see it easily, ads you make some good points, same as mr b and the rest of you, cheers for the help so far chaps thumbsup

40 Re: Power problem on 15th February 2017, 5:35 pm

mike74

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Just spray everything in soapy water or bubble mixture before you pressurise and watch for bubbles forming

41 Re: Power problem on 15th February 2017, 6:07 pm

PartyPete

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the one star club
the one star club
mike74 wrote:Just spray everything in soapy water or bubble mixture before you pressurise and watch for bubbles forming

Bloody good idea that

42 Re: Power problem on 15th February 2017, 10:34 pm

ducie54

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Be careful when adding dyes and some smoke oils as it can coat AFM and air temp sensors with a film giving false readings.

43 Re: Power problem on 15th February 2017, 11:51 pm

ADSgtir


the drop in boost pressure 1.85 to 1.65 bar would equal about exactly the power you are missing , the main problem you have now is what is it mapped to . 1.65?
So if it was say a boost control glitch ,which now reverts to 1.85 right across the revs ,your map is way off ........This usually costs dollar -lol

44 Re: Power problem on 16th February 2017, 6:13 am

PartyPete

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the one star club
the one star club
But surely at 1.65 I'd still be seeing way over the current power levels I'm making

45 Re: Power problem on 16th February 2017, 7:21 am

ADSgtir


Not necessarily , the boost pressure is just that - a pressure , this pressure creates a flow of air passing through the engine , it's the flow (volume and speed ) that gives you the torque and this torque multiplied by the RPM gives you Power .
So yes you have pressure but this is creating a flow that is leaking , Ie not passing through the engine and not producing torque and thus horsepower
Chasing maximum power numbers is a path to madness , as Bob has pointed out , torque peak and the band of torque is more important - it's this that produces acceleration in each gear and must match you driving needs , this is also balanced with lag ..
Of course people choose the simplest way of looking at performance - peak horsepower as its one easy to deal with number , so 450 hp MUST be better than 400 hp , but no this may not be true .
It's possible to have 2 identical cars , and on one car do absolutely nothing but raise the max RPM limit - boom you now make more power due the multiplying of rpm with torque .
You made 420 ft lb of torque so there cannot be any fundamental engine problem .
Each engine differs , clearances , wear, valve sealing , carbon in head and on and on , so it's often hard to do direct comparisons - usually on mapping a base line dyno is done at lower boost - from here on all comparisons are done against your own baseline numbers .
Sure you will get a relative power/torque increase against your own baseline and could predict a power (ballpark ) for any increase in boost 1 bar , 1.2 bar 1.4 bar and so on until something gets inefficient , turbo /head / cams etc .
Google a 3071 at 1.6 bar for other cars on dyno - what did they make peak power and at what rpm , then check what torque peak they made and when - I don't think you are that you are that far off

46 Re: Power problem on 16th February 2017, 7:39 am

PartyPete

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the one star club
the one star club
I've had a look and people are making more power than me on a lot less boost, I know what people are saying about it's not all about the power etc but for me it is as I've spent so much and not achieved what I set out to do so it's become a personal goal to get this bloody car to the power levels I want.

47 Re: Power problem on 16th February 2017, 10:18 am

Mr B

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gtir technician
gtir technician
1 thing you can conclude from all of above is if purely intercooler you should be able hold close to your 1.8-1.85 boost pressure target and should actually see greater pressure difference between pre and post cooler testing.
What you also got remember is as rpm increase the volume of air the engine wants increases so if turbo can't keep up then you get exactly same gradual drop in boost like you seeing.
Your turbo size not issue but exhaust gas flow or wastegate mechanically or in control settings could be the issue if no intake leaks found .
You did say you tried more boost and power same, was it able make more boost easily beyond the drop off point !, you got map or details on that run ?
Has any dyno runs been done since rebuilt turbo with new bearing cartridge, compressor blade and exhaust housing (was in pretty fudged state) ?
So many variables on a build can make a difference to end results  such as compression ratio used, rebore size, cam durations/lift, quality of any porting work etc.
Your power seems bit low though as I seen few 54C's make more torque and hp than your last graph on nothing fancy rebuild: standard ported manifold, basic cams (hks/tomei) and even arc top mount .
If you real keen on getting the best results a better cooler could net easy bit of power at likely boosts you'll be using, would be nice do some checks/changes and a run before changing that though or you never really know how much of an issue it was or how better new cooler is if do lot of changes in one hit . up to you as dyno time eats fair bit of dollar but you would learn a lot on forge cooler flow limit and if your last tuner knows anything (very surprised a UK tuner not know real world limits without doubts on a forge core as was so popular in uk)  . One thing you need conclude if no leaks available is boost pressure holding, even perhaps temporary testing with mechanical dawes type device to rule out the current controller. that all things you could do and road test (ideally with wideband).

48 Re: Power problem on 16th February 2017, 5:05 pm

GTI-R US

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Management
Management
Ok il level with you here Pete
Tbh im reluctant to say much more on this thread as its me who gets singled out on fb (im never on there) by all the idiotic twats who all claim to know everything about anything ''gtir specialist tuner included'' but infact know very little So in turn make up as much bull as possible in order to try give us a bad name! just so they get more work, and your one example of many who have been fed shite.

I see the results of their combined efforts every week from cars that have come from them and will continue to do so which is fine with me as keeps me booked solid rectifying their ''lets say schoolboy apprentice level errors'' over basic fundamentals of how a forced induction engine actually works.

But having said what ive said above

First of read what this man has written below v v v

[quote=ADSgtir] the boost pressure is just that - a pressure , this pressure creates a flow of air passing through the engine , it's the flow (volume and speed ) that helps give you the torque
Chasing maximum power numbers is a path to madness , as Bob has pointed out , torque peak and the band of torque is more important -
Of course people choose the simplest way of looking at performance - peak horsepower as its one easy to deal with number , so 450bhp MUST be better than 400 bhp , no not true [endquote]





I can pick certain pieces from what others have said who are all skirting close to the answers you need as to why theres low max power and strangely high torque..........  but no one has actually hit the correct button as of yet
But hey im just an idiot wannabe who knows nothing and whos not to be trusted if you believe what you read on fb jocolor Laughing  

So all im saying is LOOK at the graphs very closely

look at max boost pressure which is actually just under 2.1 bar spiking then tailing steadily to 1.65 yet torque continues to rise (weird is that) hint hint!

look at the poor afr line (very important) @4500 afr is around 11.5 which is ideally where it needs to be at given boost/rpm level of 2 bar (max power acheived here)
Strange that when it reaches 4800rpm power starts to tail off steadily whilst torque continues to rise and afrs lean off significantly to a ridiculously low nigh on 13afr between 4800-5800rpm thats just crazy for a tuner to let a car out the door given that boost and such a lean mixture especially with the high torque figure its ''supposedly running''

Torque is acheived as a result of cylinder air pressure & ignittion advance added in high load cells on the map, these figures can increase even more with poorly timed & incorrect duration cams fitted!!!!!
This coupled with the poor volume of fuel in cylinders / large air volume can only lead to one thing in future and thats bom

So in a nutshell Pete i can see 3 major errors here causing the above, but without doubt the biggest error was who you took it too to sort out lol

It is 99% guaranteed not to be air intake nor the intercooler you had fitted prior, that i will tell you.

I strongly suggest you take the car to someone who knows how an engine does actually work and who knows the fundamentals of how to map such an engine whilst you still have one in working order drink


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49 Re: Power problem on 16th February 2017, 6:38 pm

Mr B

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Bob got a good point on that afr as indeed it not a nice trace, but for sure more to be had here without much hassle hopefully.

50 Re: Power problem on 16th February 2017, 7:14 pm

johnny gtir

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I ain't going to pretend I fully understand it but bob showed me a lot and all I can say is if one of the best in U.K. Tells me his maps are very good then that's enough for me and I have seen and been on the receiving end of the results and the car felt great throughout the full rev range and end figures were above I expected.

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