Is is dangerous for me to run without a tune?
11-10-2009, 05:54 PM
#1
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Join Date: May 2009
Location: DFW, TX
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Is is dangerous for me to run without a tune?
Well, it's looking more and more likely that I am not going to be able to get a proper dyno tune till early next year due to cashflow problems. Is it dangerous for me to be running the Mark VIII engine with the GT tune? The last thing that I want is to mess up the new motor and have to rebuild it. It's running the stock GT fuel injectors, MAF, IAT and O2 sensors. Using the Mark VIII EGR, coolant sensor and IAC.
11-10-2009, 10:11 PM
#3
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Join Date: May 2009
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How would I go about getting the ECU flashed? Doesn't a mail order tune require a chip or tuner? I am completely new to flashing and computer tuning. Would the lack of IMRC's and an auto tranny fire off codes? I am trying to get a diablosport chip from a member here, but he has yet to send me a paypal address.
11-10-2009, 10:22 PM
#4
You have to own a handheld to use a mail in tune.
A cheaper option for you instead of a Dyno tune is to get ahold of MPT.com
http://www.morepowertuning.com/
If you have a lap top and a hand held tuner you can do a Data log and e-mail the file to them and they will send you a tune for your car. When I did mine we did 6 different data logs but they kept working on it until they got it right
But to answer your ? you should be ok. I'm sure it isn't running optimal but I'm sure it will get you from a to b.
A cheaper option for you instead of a Dyno tune is to get ahold of MPT.com
http://www.morepowertuning.com/
If you have a lap top and a hand held tuner you can do a Data log and e-mail the file to them and they will send you a tune for your car. When I did mine we did 6 different data logs but they kept working on it until they got it right
But to answer your ? you should be ok. I'm sure it isn't running optimal but I'm sure it will get you from a to b.
11-10-2009, 11:12 PM
#7
4th Gear Member
Thread Starter
Join Date: May 2009
Location: DFW, TX
Posts: 1,925
You have to own a handheld to use a mail in tune.
A cheaper option for you instead of a Dyno tune is to get ahold of MPT.com
http://www.morepowertuning.com/
If you have a lap top and a hand held tuner you can do a Data log and e-mail the file to them and they will send you a tune for your car. When I did mine we did 6 different data logs but they kept working on it until they got it right
But to answer your ? you should be ok. I'm sure it isn't running optimal but I'm sure it will get you from a to b.
A cheaper option for you instead of a Dyno tune is to get ahold of MPT.com
http://www.morepowertuning.com/
If you have a lap top and a hand held tuner you can do a Data log and e-mail the file to them and they will send you a tune for your car. When I did mine we did 6 different data logs but they kept working on it until they got it right
But to answer your ? you should be ok. I'm sure it isn't running optimal but I'm sure it will get you from a to b.
11-14-2009, 04:19 PM
#8
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Join Date: Aug 2005
Location: Whitehall, Michigan
Posts: 2,638
That's just it, I am trying to save up for a hand held. You have to have one for a shop to dyno tune anyway right? It runs fine, no codes or anything. I was leaning out at first, but I had vacuum leaks out the wazoo which are now fixed and it seems to be ok. I am not concerned about the full power yet, I just don't want to be passing someone and blow my engine apart.
Let's face it, the DOHC doesn't make much more power stock for stock than the SOHC does, and neither of them make a ton of NA power in the first place. Even if the tune is drastically off, you'll really have a hard time hurting it.
MAF systems are pretty adaptable. The ECU allows 25% long term fuel trim adjustment, with a check engine light after 10%. The MAF measures the amount of air going into the car, it knows your injector size, and it adds enough fuel to compensate. That's an oversimplification but that's what is happening.
If you're using the same size injectors that came on your other motor, I can say with a high amount of certainty that your A/F ratio is very close to perfect.
Same goes for spark timing. The DOHC probably has nearly the same spark table as the SOHC. Even if it -is- advanced a few degrees, I took my car while it was stock +7 degrees on 93 octane instead of 87 before I got spark knock while driving around, and it knocked after +6 degres at WOT.
There's a nice big buffer zone.
A WORD OF WARNING:
The GT rev limiter is 6050 RPM. That's fine, don't push it.
The GT ECU doesn't have information in the tables for anything higher than 6000 RPM. On my car, I haven't adjusted that yet. If I rev my car anything past 6k RPM, I get a big black cloud out the back and it loses power, because the ECU just guesses and retards the timing to 0 (no data left in the table).
Once it's tuned, they can adjust the tables and you'll have whatever rev limit you like. Take that DOHC to 7k, where it belongs
And don't worry too much in the mean time, you'll be fine... if you don't feel/hear spark knock now, and you have no check engine light, that means that fuel is within 10% of dead on.
If you're really worried, use your handheld when you get it and add 5% fuel and take out 3 degrees timing, then beat the hell out of it.
11-14-2009, 06:23 PM
#9
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Join Date: May 2009
Location: DFW, TX
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Most shops will require you to have a handheld to tune the car. Just plugging the handheld in won't magically make it run better - the files that are loaded on them are for mostly stock cars. Here's the scenario:
Let's face it, the DOHC doesn't make much more power stock for stock than the SOHC does, and neither of them make a ton of NA power in the first place. Even if the tune is drastically off, you'll really have a hard time hurting it.
MAF systems are pretty adaptable. The ECU allows 25% long term fuel trim adjustment, with a check engine light after 10%. The MAF measures the amount of air going into the car, it knows your injector size, and it adds enough fuel to compensate. That's an oversimplification but that's what is happening.
If you're using the same size injectors that came on your other motor, I can say with a high amount of certainty that your A/F ratio is very close to perfect.
Same goes for spark timing. The DOHC probably has nearly the same spark table as the SOHC. Even if it -is- advanced a few degrees, I took my car while it was stock +7 degrees on 93 octane instead of 87 before I got spark knock while driving around, and it knocked after +6 degres at WOT.
There's a nice big buffer zone.
A WORD OF WARNING:
The GT rev limiter is 6050 RPM. That's fine, don't push it.
The GT ECU doesn't have information in the tables for anything higher than 6000 RPM. On my car, I haven't adjusted that yet. If I rev my car anything past 6k RPM, I get a big black cloud out the back and it loses power, because the ECU just guesses and retards the timing to 0 (no data left in the table).
Once it's tuned, they can adjust the tables and you'll have whatever rev limit you like. Take that DOHC to 7k, where it belongs
And don't worry too much in the mean time, you'll be fine... if you don't feel/hear spark knock now, and you have no check engine light, that means that fuel is within 10% of dead on.
If you're really worried, use your handheld when you get it and add 5% fuel and take out 3 degrees timing, then beat the hell out of it.
Let's face it, the DOHC doesn't make much more power stock for stock than the SOHC does, and neither of them make a ton of NA power in the first place. Even if the tune is drastically off, you'll really have a hard time hurting it.
MAF systems are pretty adaptable. The ECU allows 25% long term fuel trim adjustment, with a check engine light after 10%. The MAF measures the amount of air going into the car, it knows your injector size, and it adds enough fuel to compensate. That's an oversimplification but that's what is happening.
If you're using the same size injectors that came on your other motor, I can say with a high amount of certainty that your A/F ratio is very close to perfect.
Same goes for spark timing. The DOHC probably has nearly the same spark table as the SOHC. Even if it -is- advanced a few degrees, I took my car while it was stock +7 degrees on 93 octane instead of 87 before I got spark knock while driving around, and it knocked after +6 degres at WOT.
There's a nice big buffer zone.
A WORD OF WARNING:
The GT rev limiter is 6050 RPM. That's fine, don't push it.
The GT ECU doesn't have information in the tables for anything higher than 6000 RPM. On my car, I haven't adjusted that yet. If I rev my car anything past 6k RPM, I get a big black cloud out the back and it loses power, because the ECU just guesses and retards the timing to 0 (no data left in the table).
Once it's tuned, they can adjust the tables and you'll have whatever rev limit you like. Take that DOHC to 7k, where it belongs
And don't worry too much in the mean time, you'll be fine... if you don't feel/hear spark knock now, and you have no check engine light, that means that fuel is within 10% of dead on.
If you're really worried, use your handheld when you get it and add 5% fuel and take out 3 degrees timing, then beat the hell out of it.
11-14-2009, 06:34 PM
#10
4th Gear Member
Join Date: Apr 2008
Location: New York
Posts: 1,306
If you have a tuner and a wideband you can make a safe tune on your engine. Get a low timing setting to start and get your AFR correct and then slowly add timing till you get some pinging and then back it off a few degrees (3ish)