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What happened to your ChampCar today 2021 ??


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17 minutes ago, RandomTask said:


Ehh, it's my own damn fault. I'd run a stock regulator if I could. The real reason my AFR went up is I opted for a thinner head gasket and it boosted my compression a bit. 

I think I'm confused by this.  Why would that make your afr change so much that the stock system can't keep up?  

 

Doesn't higher compression ratios essentially just make for more efficiency without actually ingesting any more air (hence same fuel requirements).

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28 minutes ago, wvumtnbkr said:

I think I'm confused by this.  Why would that make your afr change so much that the stock system can't keep up?  

 

Doesn't higher compression ratios essentially just make for more efficiency without actually ingesting any more air (hence same fuel requirements).


So you're saying the bump in compression shouldn't impact the AFR? To be honest, this is the first year I'm running AFR gauges so who knows where it was previously. Running stock intake setup. Running stock manifolds but no cats (obviously)

Edited by RandomTask
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30 minutes ago, RandomTask said:


So you're saying the bump in compression shouldn't impact the AFR? To be honest, this is the first year I'm running AFR gauges so who knows where it was previously. Running stock intake setup. Running stock manifolds but no cats (obviously)

The fuel injection doesn't know what changes you made to the engine, all it does is read the various sensors and command a pulse width based on the programmed fuel map. If a change you made improves the air flow through the engine (eg, better exhaust scavenging), the MAF should read that improvement and adjust the AFR accordingly.

 

The compression ratio change will affect thermal efficiency and improve the engine's output and fuel usage but won't change the commanded AFR. 

Edited by mender
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1 minute ago, Team Infiniti said:

Tune fuel pressure @ wot to achieve target afr and let the rest fall wherever it does?

Yes.

 

You may find that the engine likes slightly over 13:1 AFR.

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5 minutes ago, mender said:

Yes.

 

You may find that the engine likes slightly over 13:1 AFR.


I'll try and find a middle road. Again, stock injectors won't open passed 70psi and around 65psi they start "missing" if you will on injections. The motor is plenty happy at 55psi, but once the vac reference moves the pressure up near the top RPM's, you get a slight miss. 

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8 minutes ago, RandomTask said:


I'll try and find a middle road. Again, stock injectors won't open passed 70psi and around 65psi they start "missing" if you will on injections. The motor is plenty happy at 55psi, but once the vac reference moves the pressure up near the top RPM's, you get a slight miss. 

I haven't run into this issue of high pressure/not opening; sounds interesting. 

 

I used a 55 spi Corvette filter/regulator (WIX 33737?) on the Fiero and selected injectors to get the recommended 80-85% duty cycle, so haven't ventured into that pressure range. Any particular injectors that have that issue? 

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12 hours ago, mender said:

I haven't run into this issue of high pressure/not opening; sounds interesting. 

 

I used a 55 spi Corvette filter/regulator (WIX 33737?) on the Fiero and selected injectors to get the recommended 80-85% duty cycle, so haven't ventured into that pressure range. Any particular injectors that have that issue? 

Fuel injection connection has a good video displaying what happens to the stock injectors passed 60psi;
 

 

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So what would you guys do. . .

I took my car to a highly recommended shop about an hour south of me for tuning. I rec'd a quote for a dyno tuning session for $650. When we established the session, I told him the two things that need to be addressed; the lack of fuel and the timing. I also told him the car has a small coolant leak somewhere and to find it before the tuning session. He mentioned how he had tuned a bunch of these cars and wouldn't be a problem. 

Dropped the car off yesterday. When I showed up "Oh, my dyno is down, it's going to be a street tune."

Dude. I then told him "well we need to renegotiate the price". . . he dropped it to $550 which I think is still way too high, ESPECIALLY considering when I was there he also mentioned he was unsure if he was able to change the duty cycle/fuel rate with the only SW that will tune these cars. . . He said he would research it and get back to me. . .  

He shot me a message last night saying the S/W doesn't allow it. . . The S/W + tuner he's using (Dynamic Spectrum Tuner) can be purchased for $350 and is the only thing that will work on this car ('96 vette). 

So I'm of the mind "I can data log myself and see if I'm hitting knock. . .  AND I get to keep the tuner. . . "

This guy has a good reputation and a lot of people speak highly of him. That said, I wouldn't imagine the tuning being that difficult. What say champ?

Edited by RandomTask
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1 hour ago, RandomTask said:

So what would you guys do. . .

I took my car to a highly recommended shop about an hour south of me for tuning. I rec'd a quote for a dyno tuning session for $650. When we established the session, I told him the two things that need to be addressed; the lack of fuel and the timing. I also told him the car has a small coolant leak somewhere and to find it before the tuning session. He mentioned how he had tuned a bunch of these cars and wouldn't be a problem. 

Dropped the car off yesterday. When I showed up "Oh, my dyno is down, it's going to be a street tune."

Dude. I then told him "well we need to renegotiate the price". . . he dropped it to $550 which I think is still way too high, ESPECIALLY considering when I was there he also mentioned he was unsure if he was able to change the duty cycle/fuel rate with the only SW that will tune these cars. . . He said he would research it and get back to me. . .  

He shot me a message last night saying the S/W doesn't allow it. . . The S/W + tuner he's using (Dynamic Spectrum Tuner) can be purchased for $350 and is the only thing that will work on this car ('96 vette). 

So I'm of the mind "I can data log myself and see if I'm hitting knock. . .  AND I get to keep the tuner. . . "

This guy has a good reputation and a lot of people speak highly of him. That said, I wouldn't imagine the tuning being that difficult. What say champ?

Bail

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I hate the bait and switch nonsense. Even if it’s just circumstances. Finding a good reputable source for dyno and tuning can be a challenge. I worked with a great dyno guy near me but he only tunes a couple standalone ECUs and domestic OBD2 ECUs.  Not impossible to tune yourself but definitely not the easy button. 

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5 hours ago, RandomTask said:

So what would you guys do. . .

I took my car to a highly recommended shop about an hour south of me for tuning. I rec'd a quote for a dyno tuning session for $650. When we established the session, I told him the two things that need to be addressed; the lack of fuel and the timing. I also told him the car has a small coolant leak somewhere and to find it before the tuning session. He mentioned how he had tuned a bunch of these cars and wouldn't be a problem. 

Dropped the car off yesterday. When I showed up "Oh, my dyno is down, it's going to be a street tune."

Dude. I then told him "well we need to renegotiate the price". . . he dropped it to $550 which I think is still way too high, ESPECIALLY considering when I was there he also mentioned he was unsure if he was able to change the duty cycle/fuel rate with the only SW that will tune these cars. . . He said he would research it and get back to me. . .  

He shot me a message last night saying the S/W doesn't allow it. . . The S/W + tuner he's using (Dynamic Spectrum Tuner) can be purchased for $350 and is the only thing that will work on this car ('96 vette). 

So I'm of the mind "I can data log myself and see if I'm hitting knock. . .  AND I get to keep the tuner. . . "

This guy has a good reputation and a lot of people speak highly of him. That said, I wouldn't imagine the tuning being that difficult. What say champ?

 

This is an LT4 engine car correct?  Basically the same thing I have but you have an OBD2 port instead of the OBD1 port, so you have (4) O2 sensors correct?  That was the one of the reasons I kept my LT1 with OBd1 because it needed only (2) O2 sensors...   are you using the stock ECU for fuel pump control or have you just ran a on/off switch to your pump?  Like a Walbro, Bosch, etc style pump?

 

I also have a complete 93 LT1 wiring setup that is just a speed density chart ECU which means pretty much no sensors...  just has a fuel map and it goes or at lest I've been told.

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12 hours ago, Justin9 said:

 

This is an LT4 engine car correct?  Basically the same thing I have but you have an OBD2 port instead of the OBD1 port, so you have (4) O2 sensors correct?  That was the one of the reasons I kept my LT1 with OBd1 because it needed only (2) O2 sensors...   are you using the stock ECU for fuel pump control or have you just ran a on/off switch to your pump?  Like a Walbro, Bosch, etc style pump?

 

I also have a complete 93 LT1 wiring setup that is just a speed density chart ECU which means pretty much no sensors...  just has a fuel map and it goes or at lest I've been told.


Correct, LT4. I've already had the secondary O2's deleted.  ECU controls pump relay. Are you using the DST s/w? 

 


I told the guy not to tune but instead to find the coolant leak. I asked him what his rate was, and told him not to go over x hours w/o calling me. He then asked "How would you like me to find the leak?" I was tempted to say "with your mouth" but instead just said, I don't care, you're the mechanic, just find it."

Also ordered the tuner and some injectors that have more headroom and most importantly, a spare ECU that I'll practice on.  Want this car perfect for VIR next weekend!

 

Edited by RandomTask
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8 hours ago, RandomTask said:


Correct, LT4. I've already had the secondary O2's deleted.  ECU controls pump relay. Are you using the DST s/w? 

 

I am not, I had my tune and all the extra crap deleted by an internet hero...   I've never spent time doing anything more with it than code reading with some basic software since I have had other things to sort before I worried about that, but that time is getting closer.

 

I would run the fuel pump off a toggle switch for the time being to eliminate the possibility that the ecu is doing something and then slowing down your fuel pump due to it acting up...

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1 hour ago, atxe30 said:

after some false starts with other approaches, finally got down to biz on the fenders.....fenders.png.4b062ae2247a788cf2ea2cb89430cefe.png

 

Nice! I might ask you for some help. As you might have noticed the fenders on our NC could use some work....

 

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1 hour ago, turbogrill said:

 

Nice! I might ask you for some help. As you might have noticed the fenders on our NC could use some work....

 

word. i saw you all were back....welcome home to the oven!!!! lol.....

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36 minutes ago, RandomTask said:

Found out the head gasket was leaking. F***! Everything ordered to fix. Hate doing this right before the race. . .

Wouldn't that explain the coolant loss?

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