Car jerking hard at WOT

[Irace86.2.0]

Originally Posted by secho

Yes, but once it hits a 2bars, it cuts the fuel. Then there is some hysteresis to resume fueling and then it repeats and oscilates. It is not mechanical.

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Originally Posted by Kodename47

As @secho said, that's the result of fuel cut. No fuel, no exhaust gasses to spool turbo, boost drops.

Right. I think we are talking about different parts of the situation.

The drop off and oscillations are because of the tune, because of fuel cut. The fuel cut is because of an excessive amount of boost or bad boost reading. If there is excessive boost then something mechanical is most likely the problem. If it is a bad reading then the map sensor is bad or the tune is calculated for a different sensor.

Originally Posted by bryan.catano93

something to add is, at the beggining i got a base mapfor a 3bar map sensor and i have a 4 bar map. ( i didnt specify that in my mods as i wasnt sure of what options came with the kit) he then sent me another base map for a 4barmap sensor. so there could be a slight possibility he used the first base map to do the first revision? ( highly doubt it but possible). but i imagine the car wouldnt start if that was the case?

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I don't know if it wouldn't start, but things would be off. I'm really not sure.

[Kodename47]

Originally Posted by bryan.catano93

something to add is, at the beggining i got a base mapfor a 3bar map sensor and i have a 4 bar map. ( i didnt specify that in my mods as i wasnt sure of what options came with the kit) he then sent me another base map for a 4bar map sensor. so there could be a slight possibility he used the first base map to do the first revision? ( highly doubt it but possible). but i imagine the car wouldnt start if that was the case?

What are your MAP readings when the engine isn't running and at idle? Incorrect settings may well idle if they aren't off by too much at the lower end of the scale, which I can't imagine they are between a 3 Bar and 4 Bar if we're talking Omni sensors. The doc I have to hand puts the offsets very close (0.03/0.031). However, if I have this right, the tune for the 3 Bar map would give lower readings if running a 4 Bar sensor. You would need to be running a 3 Bar sensor on a 4 Bar map to give high readings. Either this is your problem (or the multiplier has been input wrong by accident to cause the same issue) or you're overboosting. The latter should really be ruled out by changing to a lower pressure spring, which you've done.

I assume no analogue gauge to compare it to?

[bryan.catano93]

Originally Posted by Kodename47

What are your MAP readings when the engine isn't running and at idle? Incorrect settings may well idle if they aren't off by too much at the lower end of the scale, which I can't imagine they are between a 3 Bar and 4 Bar if we're talking Omni sensors. The doc I have to hand puts the offsets very close (0.03/0.031). However, if I have this right, the tune for the 3 Bar map would give lower readings if running a 4 Bar sensor. You would need to be running a 3 Bar sensor on a 4 Bar map to give high readings. Either this is your problem (or the multiplier has been input wrong by accident to cause the same issue) or you're overboosting. The latter should really be ruled out by changing to a lower pressure spring, which you've done.

I assume no analogue gauge to compare it to?

yeah i changed the spring to a 6.9psi one. thats ruled out. tuner should be in tmrrw so imma have him give me some feedback. only possibility that comes to mind is that theres something inside the manifold physically blocking exhaust gases into wastegate( very unlikely because i removed all the shop towels i had blocking the manifold ports while in storage) how about a boost leak? would that cause overboost? i wouldnt imagine

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[Irace86.2.0]

Originally Posted by bryan.catano93

yeah i changed the spring to a 6.9psi one. thats ruled out. tuner should be in tmrrw so imma have him give me some feedback. only possibility that comes to mind is that theres something inside the manifold physically blocking exhaust gases into wastegate( very unlikely because i removed all the shop towels i had blocking the manifold ports while in storage) how about a boost leak? would that cause overboost? i wouldnt imagine

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A boost gauge would be nice like Kodename47 mentioned to confirm the overboost.

[secho]

Any news in this cause? I am really interested if tou already sorted out what is it?

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[bryan.catano93]

Originally Posted by secho

Any news in this cause? I am really interested if tou already sorted out what is it?

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no news. talked to my tuner and he said its deff not the tune. so i took everything apart and im in the process of installing again. but i ran into a hiccup. one of the downpipe. bolts fell somewhere in the front end and i lost it so im gonna go buy a new one tmrrw. one thing i noticed is i could of had the wastegate diaphragm not properly seated. i made sure its right this time so ill report tomorrow

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[bryan.catano93]

tuner confirmed the overboost. he said it seems the wastegate isnt seeing any pressure and the car is hitting overboost fuel cut. i took the wastegate apart again. checked it and to me it worked fine. tested it with the small spring again and i blew on the hose. i could see the wastegate starting to open. made sure i placed diaphragm correctly. put everything back together but keep getting the same issue.

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[Kodename47]

As I asked before, what is the MAP when the engine isn't running? It should be around atmospheric pressure. And the same at idle?

You now really need to verify the readings with a manual gauge or work out why the wastegate is not working.

[bryan.catano93]

Originally Posted by Kodename47

As I asked before, what is the MAP when the engine isn't running? It should be around atmospheric pressure. And the same at idle?

You now really need to verify the readings with a manual gauge or work out why the wastegate is not working.

i will check those readings today. and yeah i might need to do that. today im going to change the wastegate hose and put a new one in. ill hook up a compressor and test the wastegate. and put some tefflon tape on the turbo vacuum fitting to keep ruling out everything.

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[bryan.catano93]

Originally Posted by bryan.catano93

tuner confirmed the overboost. he said it seems the wastegate isnt seeing any pressure and the car is hitting overboost fuel cut. i took the wastegate apart again. checked it and to me it worked fine. tested it with the small spring again and i blew on the hose. i could see the wastegate starting to open. made sure i placed diaphragm correctly. put everything back together but keep getting the same issue.

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ill see if i can source a boost gauge and see what it says.

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[bryan.catano93]

update.

took a compressor and started testing the wastegate with different springs. the 7psi setup (red and natural spring) opened up at around 15 psi. red spring, wg was fully open at ~12 psi. natural spring( 1.8psi according to the manual) fully open at around 4ish psi. 4psi setup (natural and yellow) opened up at around psi.

i drove the car with the natural spring which barely made any boost. drove fine. tested the 4 psi setup and the car seems to drive well. did couple wot pulls and no boostcut, which is good. which means the turbo is sending boost signal properly, wastegate opens, but i still have an overboost issue. i did not log anything because i didnt have my laptop with my. ill do some. logging tmrrw, send it to tuner and ill post a copy here so you guys can check them out.

i have 2 hypothesis, one being the springs rates are a bit off(unlikely) . or i am somehow creating a leak in the diaphragm installing the stiffer springs( wg is in the car so its a bitch to get the stiffer springs in.)

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[Irace86.2.0]

Originally Posted by bryan.catano93

update.

took a compressor and started testing the wastegate with different springs. the 7psi setup (red and natural spring) opened up at around 15 psi. red spring, wg was fully open at ~12 psi. natural spring( 1.8psi according to the manual) fully open at around 4ish psi. 4psi setup (natural and yellow) opened up at around psi.

i drove the car with the natural spring which barely made any boost. drove fine. tested the 4 psi setup and the car seems to drive well. did couple wot pulls and no boostcut, which is good. which means the turbo is sending boost signal properly, wastegate opens, but i still have an overboost issue. i did not log anything because i didnt have my laptop with my. ill do some. logging tmrrw, send it to tuner and ill post a copy here so you guys can check them out.

i have 2 hypothesis, one being the springs rates are a bit off(unlikely) . or i am somehow creating a leak in the diaphragm installing the stiffer springs( wg is in the car so its a bitch to get the stiffer springs in.)

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So I am pretty sure I have figured this out, and you messed up bro...

The product page says the Turbosmart 38mm wastegate has a 74mm diameter diaphragm/master collar size. From the table, the only spring you should have in there is the pink spring to achieve 7psi. Black alone will achieve 3 psi, grey will achieve 5 psi, pink 7 psi and red 14 psi. According to the second chart the black and grey are inner springs, so they can't be combined, but you could do the pink with the black or grey to make 10 or 12 psi, respectively.

The yellow and the raw springs are for 84mm and 98mm diaphragm wastegates, respectively, which are the Turbosmart 45mm and 50mm/60mm, respectively--again, not the 38mm.

Where did you get these other springs?

I would make sure you have the right setup. Maybe I am confused, but it seems the wastegate should have come with one 7psi spring--the pink spring. If you wanted more boost you could add the black to the pink to get 10psi or the grey (not raw) to the pink to get 12psi or put a red spring in solo to get 14psi.

https://system.na3.netsuite.com/core...=clear&whence=

[bryan.catano93]

Originally Posted by Irace86.2.0

So I am pretty sure I have figured this out, and you messed up bro...

The product page says the Turbosmart 38mm wastegate has a 74mm diameter diaphragm/master collar size. From the table, the only spring you should have in there is the pink spring to achieve 7psi. Black alone will achieve 3 psi, grey will achieve 5 psi, pink 7 psi and red 14 psi. According to the second chart the black and grey are inner springs, so they can't be combined, but you could do the pink with the black or grey to make 10 or 12 psi, respectively.

The yellow and the raw springs are for 84mm and 98mm diaphragm wastegates, respectively, which are the Turbosmart 45mm and 50mm/60mm, respectively--again, not the 38mm.

Where did you get these other springs?

I would make sure you have the right setup. Maybe I am confused, but it seems the wastegate should have come with one 7psi spring--the pink spring. If you wanted more boost you could add the black to the pink to get 10psi or the grey (not raw) to the pink to get 12psi or put a red spring in solo to get 14psi.

https://system.na3.netsuite.com/core...=clear&whence=

i have a pte wg. and the red and natural spring( gray in the chart) are for a 6.9 psi set up. i still overboosted with that setup somehow. yellow and natural spring is what i have now. the air compressor gauge read around 9ish psi when fully open with that setup. ( not sure how accurate gauge is at low. psi) but i didnt hit fuelcut with that setup. logs today will say how much boost i am hitting with that setup.

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[Irace86.2.0]

Originally Posted by bryan.catano93

i have a pte wg. and the red and natural spring( gray in the chart) are for a 6.9 psi set up. i still overboosted with that setup somehow. yellow and natural spring is what i have now. the air compressor gauge read around 9ish psi when fully open with that setup. ( not sure how accurate gauge is at low. psi) but i didnt hit fuelcut with that setup. logs today will say how much boost i am hitting with that setup.

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Bummer. I was sure that I had figured it out. Do they offer a PTE wastegate as an option or on earlier versions? Because the current version has the Turbosmart 38mm as the wastegate that comes with their kit.