2g Pistons on 1g Rods, Very First Start Up Question

[greekgodchaos]

So I am almost ready to fire up my car for the very first time with everything rebuilt, and I had a question since I put 2g pistons on my 1g rods. I came across this article in the Tech Section http://www.dsmtuners.com/forums/articles-engine-fuel/275878-2g-pistons-1g-big-rods-need-timing-control-h20-meth-injection.html and it says that its very important that I have my overall fuel supply increased in order to avoid knocking and engine damage.

I was under the impression that for the break-in period I should be using 450cc injectors and sticking to factory boost levels; here is my setup:

450cc 2g Injectors
Rewired Walbro 255lph
Aeromotive AFPR
3" GM MAF with Translator v2.02
eBay Evo III 16g
3" Exhaust
Wideband O2 Gauge

I have ECMLink v3 Lite, but my EPROM ECU is chipped for 720cc Injectors...which I do not have currently; so I am running my NON-EPROM ECU with the 450cc's; should I change anything in order to meet the "requirements" for running 2g pistons on 1g rods and the increased compression?

Any and all advice is greatly appreciated and I thank you all in advance.

 

[ed1380]

stock injectors. stock ecu. stock fuel pressure. You're good to go. Just set the maft a click on the safe side.

I'd be more worried about how long that 16g will last.


Follow the motorman break-in and you'll be good. Just be sure to check the gauges. If you don't have an oil pressure gauge I would highly recommend getting one. It's the 2nd gauge everyone should get, even before modifying the car.

 

[WES_393]

The "issue" with running 2g pistons with stock 1g tune is the higher compression ratio met with very aggressive timing. In order to avoid knock, you would want to drop timing. Without a tuning device capable of doing so I would personally wait for the break in.

On a second note, if your EPROM ECU is chipped for 720's, won't removing the chip and installing the Link chip solve that problem?

 

[greekgodchaos]

On a second note, if your EPROM ECU is chipped for 720's, won't removing the chip and installing the Link chip solve that problem?

The chip that I received from ECMLink was burnt for 720cc Injectors, are you suggesting buying a blank Link chip?

More input is greatly appreciated, thanks a bunch guys!

 

[ed1380]

If you bought "ecmlink 2.5" that chip is programmable using the cable and ecmlink software. They just program it to your injector size before shopping as a convenience. If you bought just a chip for 720injectors, then you can't program it. You'll need to send it to someone who can.

 

[scoby41]

Hmmm, I'm about to drop the same combo into my completely stock gsx....

 

[My1GLaser]

The chip that I received from ECMLink was burnt for 720cc Injectors, are you suggesting buying a blank Link chip?

More input is greatly appreciated, thanks a bunch guys!

It was just set for 720 inj which means the global was changed to -41.6%

Change the global to 0% if you are running stock inj. It is a re-flashable chip and it can be changed on-the-fly which the click of a button.

Zero out your MAFT and do all the tuning with ECMLink!!!

If you are breaking in a new motor then you need to lean out that fuel curve or you will be wayyyyyy too rich under boost and run the risk of washing down the cyl walls. Lean that thing out to 11-11.5:1 @ WOT for the break-in.

Check your base timing and make sure it is 5* BTDC. Pull a 2* degrees across the board so you don't knock. But pull 5* at 5.5k, 7* at 6k & 3* at 6.5k. That will have you at 16-17* from 4k to redline. I will attach a picture of the stock timing map so you see why the extra timing needs pulled at those rpms. Plus you will see why the 8.5:1 pistons are a little much on pump gas with the stock 1g timing map.

I ran 12-16 psi boost for 20ish miles. Then I progressively turned it up over the next 200 miles. I was at 20-22 psi within 200 miles. Cyl pressure forces the rings against the cyl walls and that's what seats them. Let off the gas and let the car engine brake alot. The vacuum shoots up to like 25inhg and really aids in the process. My car had perfect compression by 100 miles!

 

[greekgodchaos]

It was just set for 720 inj which means the global was changed to -41.6%

Change the global to 0% if you are running stock inj. It is a re-flashable chip and it can be changed on-the-fly which the click of a button.

Zero out your MAFT and do all the tuning with ECMLink!!!

If you are breaking in a new motor then you need to lean out that fuel curve or you will be wayyyyyy too rich under boost and run the risk of washing down the cyl walls. Lean that thing out to 11-11.5:1 @ WOT for the break-in.

Check your base timing and make sure it is 5* BTDC. Pull a 2* degrees across the board so you don't knock. But pull 5* at 5.5k, 7* at 6k & 3* at 6.5k. That will have you at 16-17* from 4k to redline. I will attach a picture of the stock timing map so you see why the extra timing needs pulled at those rpms. Plus you will see why the 8.5:1 pistons are a little much on pump gas with the stock 1g timing map.

I ran 12-16 psi boost for 20ish miles. Then I progressively turned it up over the next 200 miles. I was at 20-22 psi within 200 miles. Cyl pressure forces the rings against the cyl walls and that's what seats them. Let off the gas and let the car engine brake alot. The vacuum shoots up to like 25inhg and really aids in the process. My car had perfect compression by 100 miles!

Damn thanks dude, this is excellent information. Ill swap my ECU's out tomorrow and get the settings dialed in before I fire it up. Looks like I am gonna be busy tonight studying the in's and out's of ECMLink

If you bought "ecmlink 2.5" that chip is programmable using the cable and ecmlink software. They just program it to your injector size before shopping as a convenience. If you bought just a chip for 720injectors, then you can't program it. You'll need to send it to someone who can.

I bought v3 Lite on its own, never bought any earlier versions.

 

[DSMTyson]

Damn thanks dude, this is excellent information. Ill swap my ECU's out tomorrow and get the settings dialed in before I fire it up. Looks like I am gonna be busy tonight studying the in's and out's of ECMLink

Its not hard. Just follow the initial setup videos on their site, punch in the stock injector size, and load the Evo 8 timing map from the data log file that comes with the software and back timing off 2-3 degrees to be safe using the sliders(just to make things easy).

 

[greekgodchaos]

Its not hard. Just follow the initial setup videos on their site, punch in the stock injector size, and load the Evo 8 timing map from the data log file that comes with the software and back timing off 2-3 degrees to be safe using the sliders(just to make things easy).

Any reason why I would use the Evo 8 timing map? Just curious!

 

[DSMTyson]

The Evo 8 map isn't as aggressive as the stock 1G timing map, and given that you will now have the same compression ratio as an Evo 8, it just seems like a good starting point. Makes more sense to me. You don't want to be fighting knock when you are breaking in your new short block.

 

[My1GLaser]

If you run the Evo map then you probably won't need to pull any timing. It's pretty conservative as it is. I have a map on my laptop at home. I can post a pic later so you can compare.

 

[greekgodchaos]

I would really appreciate it if you could, the more information I have getting into this the better. PLUS, anyone in the future can reference this as well when about to fire up a 6-bolt with the 2g Piston/1g Rod combo for the first time!

 

[greekgodchaos]

Question!!! Should I set my timing to mirror a 2g? Since I have 2g 85.5mm Pistons after all. Here is the link: 2gtimingin1gecu [ECMTuning - wiki]

 

[My1GLaser]

Every car responds differently. It definitely wouldn't hurt to try the 2G curve, but you might have better overall performance with the more aggressive 1G timing map if your car responds well to it. Here is a link to the loadable Evo timing maps available for V3lite. v3liteconfigs [ECMTuning - wiki] You can still use the link you posted and move the sliders to match the 2G if you want. Only use one or the other!

After your motor is broke in, the best advice I have is to try them out and see what the car likes. Use the same stretch of road and do some back to back 3rd gear pulls with the different timing curves. Compare spool characteristics, 70-90mph acceleration times (or 60-80 times) and overall feel of the car, plus see if it knocks or not. You will be able to see what the car wants.

During the break-in, just don't run too rich, make sure your fuel trims are in line, lean it out and break in the motor with a little less aggressive timing curve than the 1G one. (whichever way you choose to do that) You need to be focused on breaking the motor in and not battling knock, so do what you need to for a couple hundred miles. You should be doing short 2nd & 3rd gear pulls right from the start anyway, and will already have datalogs to check your tune along the way.

FWIW, I still run the 1g timing maps. I have 9:1 CR pistons and ran 26-28 psi on my 18g with 18-19* peak timing when I was running pump gas. I blend 60% E-85 now and run 32-33 psi on an HX35 with 21-22* timing

Also, the link in your very first post is for people without timing control. You have ECMLink, so you don't need to worry about that.