Boost returned, but, engine power presentation has changed?

[herbiemercman]

Hi Guys, My boost has been restored by replacing a torn boost pipe and adjusting the wastegate spring, however one thing i do miss is the sharpness / torque i used to have at the initial accelerator pedal, basically i have to cross a sort of doseile initial pressing of the accelerator and get into the real boost, it is a sort of delay?

Do any of you know why this has happened? The only thing that has changed from the original NAT build is the 3" Jap Parts exhaust system and a reduction of CR from 10to1, down to 9to1, and the adjustment of the wastegate to a higher release spring setting. ? Herbie.

[Scooter]

Perhaps you are just noticing the non NA'ness now. I mean before the NA-T you had on a stock gasket means you get the best of the NA's qualities, nil lag at low rpm and standard good NA throttle response, so any map 'just' deals with the boost that comes in fairly early too I'd imagine? and is limited by the wastegate. Writing this I'd imagine any 320bhp NA-T, that's not stupidly rich, has a pretty much better everything drivability wise (except longevity?) than a stock 320bhp TT?

 

The stock TT will have perfect mapping though for the standard lower compression ratio and so I suspect that now your NA-T, combustion chamber wise is like a TT, it doesn't currently have the map to match and help it?

 

So to work optimally or at least get the benefit out of the new thicker head gasket, I think you'd need to map the lower end better for the new CR and then map for the higher boost that the new gasket affords you at higher rpm's.

 

If the map is as was and you've increased the wastegate spring and so are runnning extra boost, then potentially you are running the risk of running lean at higher boost? (Perhaps you had an slightly safe and rich AFR on the old setup and now you are marginal and have no safety margin?)

 

What I'm saying is with no map change, the wastegate adjustment could give you safe, borderline to melting piston conditions, and so far you're guessing to a degree? Apologies if that's not correct, i'm no expert in mods this is just what I think is the case from the threads of yours?

[Noz]

Without a dyno print comparison. You might just he getting used to it.

 

Before you start a long what-if thread. Get it dynoed if you think theres an issue and compare your torque and hp values per rpm.

 

Your question will not be answered without some data buddy. Dont forget we get used to speed perception.

 

Get a few power runs locally at a dyno and see if theres a difference. I got used to my 417hp na.t and thought similar. But was just perception.

[herbiemercman]

Thanks guys, that makes a lot of sense, my problem is locating a mapper that will get involved with Greedy Emanage piggy backs, if there is one, then i know i would have to travel, all be it that would be ok.

Just a point for Scooter, the performance post NAT was sharp and responsive at the bottom end, you just touched the accelerator, also the spooling noise was instant, NOT, half way down the accelerator pedal. I am still glad i have my boost back, and it flies when you put the boot down. Still no positive pressure readings on my boost gauge, just negative? Herbie.

[Style]

You NEED to get the car to a mapper mate. Or at the very least, on a dyno for a detailed printout. No doubt about it now. Spend the money now or you'll end up spending it twice over having to replace a knackered engine. Are you sure it was the wastegate that you adjusted as well? I've never seen a wastegate with any sort of adjustment screws/nuts on top. That sounds like a blow off valve you could be looking at which looks a little like this.

 

 

If you've played around with the wastegate settings then God only knows how much boost you're running. Couple that with no AFR gauge and you could well be running lean when you put the foot down...not good. Your car was mapped to 1 level of boost and if you're running more than that after playing with the wastegate then your map is going to need adjusted to compensate.

 

If your now running less boost from the wastegate changes, then you'll absolutely feel the drop in power. Having tried 2 boost gauges which both read -ve tells me there's something else wrong. Unless you mean -ve when the car idles? Take it out for a blast and see if it's reading +ve at the top 2 second gear with your foot down. That's where you want to see +ve pressure

[Mo Reviews]

Just a friendly pointer, following your issue is becoming increasingly difficult as there are so many different threads covering the same thing... perhaps you could stick to one thread and just update that?

Edited February 7, 2020 by Mo Reviews
Spelling. (see edit history)

[Noz]

Just a friendly pointer, following your issue is become increasingly difficult as there are so many different threads covering the same thing... perhaps you could stick to one thread and just update that?

 

Couldn't have worded it better.

[sidewaysdan]

If you look at his wastegate in his other thread. You can see the screw he’s taking about.. I thinks it’s the preload on the spring.

 

Herb you defo need to get it checked properly mate as the guys said before you melt a piston or two

Edited February 7, 2020 by sidewaysdan (see edit history)

[herbiemercman]

Hi Guys, Yes it is a dump valve, spring set at 12PSI, i still do not know what the single little pipe connection does?

With reference to the suggestion of having used just the one thread, i thought at the time that it would put things more clearly for the different problems that developed, and also i thought a new thread would get noticed more.

Anyway there has been lots of help from you all and this has educated me and helped solve many of the issues.

I am currently looking for a good mapper. Herbie.

[Style]

The little pipe/hose is what lifts the dump valve open when you come off throttle. Your engine returns to vacuum and this creates a big enough differential between the positively charged intake pipe and the negative pressure in the small hose to open the dump valve, allowing the pressurised air to escape. The spring and adjustment screw is used to stop it being forced open from the intake piping side when under full boost.

 

It still looks very familiar to what sidewaysdan's wastegate looks like, so I'm not sure what to believe anymore

 

Is it on the exhaust manifold? Or on the intake pipework going to the engine?

[Noz]

Never heard of a dump valve being set to 12psi.

 

I think theres some confusion here..

[herbiemercman]

The pipe goes from the boost pipe on the outlet of the turbo where i assume the highest pressure can be measured. Craig Allard (Rocket Dog Racing), the stage 1 builder blocked off the pipe in the middle so the dump valve was sealed and so was the output on the turbo boost pipe. He told me that is how he wanted it and the dump valve just relying on the pressure compressing the spring and opening, it worked very well. I tried fitting a new pipe with pressure readings being involved, but you could not see any difference in the performance etc. ?

When my boost recovered and that just gave me a bigger exhaust system, lower CR, then the dump valve was sticking open, even on tick over? So i adjusted the spring a little and the valve was ok and brought back my spooling noise. Both Craig Allard, and i think Chris Wilson? did not think i would be running lean? I will still look for a re-map. Herbie.

Edited February 7, 2020 by herbiemercman (see edit history)

[Mo Reviews]

The pipe goes from the boost pipe on the outlet of the turbo where i assume the highest pressure can be measured. Craig Allard (Rocket Dog Racing), the stage 1 builder blocked off the pipe in the middle so the dump valve was sealed and so was the output on the turbo boost pipe. He told me that is how he wanted it and the dump valve just relying on the pressure compressing the spring and opening, it worked very well. I tried fitting a new pipe with pressure readings being involved, but you could not see any difference in the performance etc. ?

When my boost recovered and that just gave me a bigger exhaust system, lower CR, then the dump valve was sticking open, even on tick over? So i adjusted the spring a little and the valve was ok and brought back my spooling noise. Both Craig Allard, and i think Chris Wilson? did not think i would be running lean? I will still look for a re-map. Herbie.

 

"Think" is the keyword in the penultimate line of your post. Nothing can ever be said with any certainly until we have data. Sadly, we will not have the required data until you get your car on a dyno for a simple dyno run with some basic data logging.

 

As for the numerous threads, I think all of your concerns stem from a singular issue. Starting numerous threads about the same issue will only serve to fuel confusion and diminish your chances of someone having a eureka moment and solving all your problems. When you post something to an old thread, it brings that thread to the top of the list of threads thus creating the same effect of posting a new thread...

Edited February 7, 2020 by Mo Reviews (see edit history)

[herbiemercman]

Yeh i agree about the thread issue. The lack of data has been a problem for me BUT i have to travel far to get the data and the car has been too poorly to travel.

[Noz]

I've always advised getting particular gauges fitted when doing a turbo install. Purely for this reason. Espcially AFR.

 

It's usually a typical part of the list. Definitely work to get one.

[Mo Reviews]

Yeh i agree about the thread issue. The lack of data has been a problem for me BUT i have to travel far to get the data and the car has been too poorly to travel.

 

Any chance you could get it recovered to and from a rolling road?

[David P]

I am currently on my fourth and fifth Supra relapse and desperately searching for a cure from this debilitating condition...

 

herbieman, 3 times a day before meals, will sort that for you.

[Mo Reviews]

herbieman, 3 times a day before meals, will sort that for you.

 

[herbiemercman]

It is time we had some banter i have had much frustration with my "poorly car," however i have learned a lot and well on the way to recovery.

On a more serious note, why do many members put the AFR almost on the same footing as the timing belt? I fully appreciate that serious engine damage can occur, but what is the likely hood of your AFR changing once the car tuning has been set up?

I would bet that many members do not have an AFR gauge fitted, they are expensive and many of us probably are not aware of the potential for your tuning to suddenly start to run lean and end up with a screwed up engine.?

If my cylinder head gasket had not failed on me, then i would still be enjoying my car's performance as it was following the NAT conversion, you could say "ignorance can be bliss". Herbie.

[Noz]

You assume the tune was correct.

 

Afr can drift if something fails. Sensors incorrectly function.

 

Afr monitoring is a health check. Helping you indicate problem solving.

 

With fitting a turbo. To a car which has a piggy back. You want as many outputs to measure as possible.

 

You are a great example of tuning without available information and what frustration is can be. Thus why so many advise it.

 

Afr is really a bit like your basic blood pressure or heart rate check when you tell the doctor you dont feel great.

 

Many members wont have one and will never need one. Fitting a turbo. Going single or big power. Are ideal situations where an afr gauge is truly advised.

 

Piggy back ecu capabilities mean the gauge is your verification of the engines basic running operation. I sold my gauge as my ecu displays my output measures on a small touchscreen. But it also tells me the max afr and if theres any warning. You wouldnt go to the doctor with chest pain and not allow him to take some measurements!

 

You can buy them for around 110 second hand and they arent considered an expensive item. Not after youve fitted a turbo! Just a part on the usual turbo fit list.

 

If your engine never had any problems and there was no risk of problems maybe youd never need an afr gauge. But its crucial because in reality you need that health check buddy. With further potential issues you need to know if the tune is happy.

 

Without a numerical value to compare your situation you will only be scratching your head for longer my friend. Get a gauge. Get it dynoed. Both for under £200. Pretty cheap if you get information that helps you understand any variation.

Edited February 8, 2020 by Noz (see edit history)

[Mo Reviews]

Excellent advice right here. For an initial outlay of circa £200, you could potentially save yourself several thousand pounds in repairs!

[herbiemercman]

Great reply NOZ, you just sold me a AFR gauge, are they alpha or numeric, if i have to link the readings i see with any of my data from the NAT build,to see if everything is OK, then i have none? I know AFRs are ideally between 12to1 and up to 14to1,do the gauges give this kind of read out? or it will be no use to me.

I did an HND in mechanical engineering and there was a section on combustion theory, so with reference to engine damage caused by a very high temperature burn, i can see why the engine damage occurs. You will know that most ICE engines have an EGR, (exh.gas.recirc), to limit NOX, (nitrouse oxide) in the products of combustion, to help aessmatic people's breathing problems.The engine designers achieve this by recirculating the exhaust gasses into the combustion chamber which vitiates the flame / lambent yellow flame, and brings down the temperature of the flame , consequently reducing NOX to a minimum, so the reciprocal is a very pale blue lean flame which is very hot and eats pistons.

Changing the subject. I once worked at Wall's End in "Geordie Land" and sampled peas puddin and Newky Brown on draught, happy days. PS: Sorry Noz, i just realized i have got you mixed up with Style, the geordie, you would be creamed teas and champagna.lol. Herbie.

Edited February 8, 2020 by herbiemercman (see edit history)

[Noz]

I also completed a HND in mechanical engineering. You need to put down the combustion theory principles and start reading some basic AFR tuning guides mate.

 

AFR gauges give a digital number. They are a wideband sensor display (dont ask me what this is. Google it as it will also explain comparison against OEM o2 sensors).

 

I've done much reading on the important and benefits from each typical metric the typical aftermarket ecu offers. It really helped me understand terms and turbo converting principles.

 

My advice for you today would be ignore the principles of combustion from an advanced viewpoint and google basic tuning methods as these will be more relevant to your situation.

 

No cream teas this way! Just fields lol.

[herbiemercman]

Cheers Noz, I have just dug out a pressure gauge i had from a field test control system we were developing, it is just a simple gauge measuring + only, bar and psi, i connected it up to a bicycle pump and measured 1 bar circa 15 psi. So will rig this up on the supply pipe on my inlet manifold, which feeds the boost controller, and see if my gauge is working? Herbie.

[Style]

Great reply NOZ, you just sold me a AFR gauge, are they alpha or numeric, if i have to link the readings i see with any of my data from the NAT build,to see if everything is OK, then i have none? I know AFRs are ideally between 12to1 and up to 14to1,do the gauges give this kind of read out? or it will be no use to me.

I did an HND in mechanical engineering and there was a section on combustion theory, so with reference to engine damage caused by a very high temperature burn, i can see why the engine damage occurs. You will know that most ICE engines have an EGR, (exh.gas.recirc), to limit NOX, (nitrouse oxide) in the products of combustion, to help aessmatic people's breathing problems.The engine designers achieve this by recirculating the exhaust gasses into the combustion chamber which vitiates the flame / lambent yellow flame, and brings down the temperature of the flame , consequently reducing NOX to a minimum, so the reciprocal is a very pale blue lean flame which is very hot and eats pistons.

Changing the subject. I once worked at Wall's End in "Geordie Land" and sampled peas puddin and Newky Brown on draught, happy days. PS: Sorry Noz, i just realized i have got you mixed up with Style, the geordie, you would be creamed teas and champagna.lol. Herbie.

 

Lol i work in Wallsend down by the quayside. Originally a Scotsman though so I don’t understand the fascination everyone has with the brown ale down here