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Tps position and fueling at half load and full

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So been road tuning my car first thanks for the knowledge it's been amazing to see how much faster my car has gotten! I noticed some tonight tho my car take off like a banshee at 50 throttle and revs strong till red line as I move tps slowly to 75+ but if I go 100 to redline my car bogs at 5800 and falls flat on its face... Same boost same VE area am I naturally leaning it out with my foot ore am I missing something?

Are you not monitoring your AFR's? What about knock?

So yes I am running a wb. Knock not so much yet I have a device. Been running on a gica timing copy then setup for boost up top it's very safe. I guess my question needs to be re articulated better... At wot fast floored 100% the car hits a dead spot and falls on it face. If I easy the pedal to 100 that doesn't happen same kps and same target afr.. So my question is how does the ecu know how to control the fuel for 75 tps vs 100 at a fixed kpa. All my test are done at 2000 rpm ramp runs the dead spot is right at 4600 to 5200 it makes me have to shift and then it's fine it's only in 1 and 2, 3 pulls right through.. In short my car is faster at 75 % toe then 100

It really depends on how your map is laid out, if you have no row between 75% and 100% then the ECU will interpolate between these values.

If your AFR's and MAP are stable then I'd be looking at your ignition map, make sure you're not entering a knock limited area as that RPM range is where peak torque is generally on stock turbo's on the RB26.

If you give us some more information on your setup then it will allow us to make a more informed answer to your question. What engine, what mods, what fuel etc?

Okay cool thanks again for you help I will take some screen shot of my VE and spark maps. What else would you need to know I'm running MS I could post some logs if you had a way to view them

Yeah, of course. Every bit of info helps

98 VW golf gti vr6 turbo 8:5:1 cr, ported and polished, race valves, springs, 262 cams, custom short runner intake, water cooled bb t4t3 60 trim turbo, forge wossner pistons, dressed rods, balanced rotating mass, custom oil pan with baffle, limited slip 5 speed trans, ID 1000's Running strong on ms2

it started life as a kinitic motorsports stage 3 kit the only think i change beside mentioned was i did the same garret turbo but a bb chra t3/t4 60trim

Okay i think i have some usable data there are some major in inconstants in the log. i notice tho when it fell on its face the injector duty cycle drop to zero as far as i no i have nothing set to trigger that..

first is a ramp run in third i notice that i'm not as dialed in as i thought

second it a drag race

third is the same as second except i went fuel cut and stopped

Attached Files

have you looked at your boost levels in your drag log?

At 6.7 seconds (4589 rpm) your boost hits 12 psi, your PW and PW2 (injector duty?) have a massive drop to zero as if you've hit a limiter, the ignition also drops here, the same again at 6.998 seconds. Is this a flat shift?

At 7.6 seconds into the log, 5580rpm the boost levels drop, AFR's go richer and your VE also drops, this is probably the flat spot you're talking about. I've not had the chance to look at your map yet but I'd be looking at your boost control and also the fuel map

So I just noticed that last night after posting it mainly the one at 5800 I didn't notice the one lower I was using a launch control on the drag race one, the one that went complete lean was without control on. Some one on ms forum told me to look at a rev limit coolant controlled I have a over temp limit set there so I'm wonder if I'm getting a spike and hitting that. If you would be will to help me I'd great apreciate it! I've learned a lot lately but I feel my ability a need a bit of grooming

I'll take my laptop home tonight and have a look over the map and logs together. should have some feedback for you in a few hours

Thank you

Also if you don't mind could you take a look at my AFR's i'm trying to shoot for a 12.3 at roughly 11 psi. I'm not 100% sure if that is too lean for my set up though. Also that spike that you had mentioned were you think that my map fell flat on its face I added a lot of resolution before that and during that Spike to kind of build up the map in that area but I'm wondering if I went about it the wrong way I'm wondering if I should maybe have taken away resolution, anyway that's an area that I've been kind of fighting in the car for a little bit so any help would be wonderful! I've also been fighting my acceleration enrichment it seems that since I put the ID 1000 injectors and I have hardly any room to add any fuel without getting rich spikes during excel I have started to realize that maybe I need to set up my thresholds up so that it will not add fuel lower than 1.2 ms or whatever it's going to take if you're following me so another words when the Excel enrichment happens it's already adding 1.2 instead of scaling from 1 to 1.2 does that make sense. I think you'll see what I'm talking about in my AE. The reason I say this is because at the very first spike it'll go rich but then as the acceleration tapers off I get lean condition.. I believe this can be seen as I stabbed the gas on my ramp run it takes a minute for the fuel to start following the target

What are you using for boost control?

It's a AEM true boost controller keep in mind that I was using launch control at the start of that run and it could very well be peaking and spiking weird because of that, launch control uses spark and fuel as a cut I believe the rest of my limits are set for fuel and spark cut

Just working off of your drag log it looks like you've boost control issues, after 5200RPM it starts to lose pressure in the second gear section.

The 3rd gear section there's 2 points where the fuel is cut off and when you've backed off the throttle slightly the timing pulls back to 5 degrees momentarily, strangely, the boost is steady throughout the entire gear even when you start to lift off. Also on this section your intake temps are starting to go about 60 degrees C this is going to start affecting power

If there's any chance to run boost control through the MS2 I'd ditch the Tru-boost and do just that, you want repeatability and external controllers can't match a good tuned ECU controlled set-up

Is there any chance that a slight boost leak could be causing this issue the reason I ask is a couple months ago I did a a good hard pull my car and the turbo almost started sounding like it was grinding on the impeller, I took the turbo off and checked everything was fine nothing was grinding but basically it's like a high-pressure squeak. Best describes like a supercharger wine almost. It seems to do that most in third gear and top of second

It could be because of a boost leak, the grinding noise I would be worried about though. I've had something similar and it was the turbo shaft kissing the thrust bearing and failed soon after. hopefully this isn't the case with yours.

I've only heard it at higher boost pressures like a above 5500 RPM and 11+ psi, I check the shaft play there doesn't seem to be anything odd or weird about it so I I believe it's just a boost leak.

Also with that noise I was describing it happened all of a sudden like a hose burst or cracked or something it was not progressive and when it happened I was under full boost 18 psi. tonight I went out and drove the car and did not have any issues with it falling on its face I did change the coolant controlled rev limiter up a little higher I'm wondering if I was getting a spike that was not showing in the data log, I do have smoothing set pretty high on my coolant and manifold temperatures as well as battery voltage.. Sorry if I'm asking for too much help or asking too many questions Chris the only one that I really have left to ask is. is it best to do tuning all in one day so that you get a constant ambient temperature I've noticed that tonight driving my car my AFR's are spot on but a couple days ago when it was warmer they were off I am using mega squirt ideal gas law so I'm not 100% sure on how to tune it I feel like I can tune the TPS related one better like found on vems or the Motec system, all the ones that Andre has been teaching us on!

Anyway I really appreciate your help I know it's a pain in the butt to look at everybody's data logs and you've been great help to a lot of people on this forum so I really appreciate it!

It no bother, that's what we're here for.

It's always good if you can to re-visit a tune with different ambient conditions, this usually isn't possible with tuning shops. If your tune appears to be out slightly then I'd only adjust the compensations for the temperatures that have changed, it shouldn't take much.

I guess Chris I don't understand how I can adjust my compensations if I've tuned half my VE table at one temperature and the other half of my VE table at a different temperature? Have you had a chance to look at my Maps and my tune is there anything that was sticking out to you that I need to look at I'm particularly interested in my target afr.

Hey Chris I want to run something by you I was told to that my IAT timing retard might be cause my flat spot on average my temps about 3.5 degree of timing right around where my car falls flat... Could that cause the drop in boost?

I wouldn't have thought so. The increase in IAT might cause the turbo to go out of its efficiency range. Is your boost solenoid on the same duty cycle?

Yes fixed duty cycle from start to finish. The one thing the AEM trueBoost Gauge has is a waste gate spring crack pressure setting I have that set that eight psi which is what my spring pressure in my wastegate. I believe that just help smooth the spikes that you would otherwise get if you didn't have a compensation set up for that at least that is what is explained in a YouTube video of them setting it up?

Just a heads up in order to fix a lot of my issues that I know I have it's gonna take me a couple weeks, the ford Iac that I need to put on my throttlebody won't clear my radiator fans so I'm having to buy thin electric fans and one of them is back ordered that has the two speed option!

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