2G Maf and 550's

[trixtert]

I have a buddy here in calgary with a 1G 2.3Stroker motor 8.5:1 compression a TDO5H 20G Turbo and as the title says a 2G MAF and 550's and thats it for tuning.

What I mean is he has no tunning whatsoever has a datalogger and a Boost guage thats it and @ 10PSi he ran a 13.2@113mph. His fuel trims seem to be ok he doesnt knock almost at all the odd time he will get one or two counts but thats it. He is going to up the boost to 15PSi in hopes of running high 12's. He tells me that the 2G Mas accounts for everything and he doesnt need any tunning.

Is it true that the 2G Mas with 550 injectors is suffiecient to run high 12's low 13's?

 

[andymoraitis]

While he may be able to run his 12's, the tune to do so is far from optimal. Without some means of controlling his injectors, he's running very rich and with no additional tuning device, his air/fuel ratios are rich to the point of being in the gutter. The 2G MAF was calibrated for stock injectors (450's) so if he wants to run properly, he either needs an AFC, MAFT, DSM Link or a chipped EPROM ECU to control them.

He should see a night and day difference once he has the capacity to compensate for the injectors and lean the motor out safely although those injectors aren't large enough to exploit the full power of the 20G.

Hope that helps,

Andy

 

[trixtert]

Ooops, i forgot to mention he does have a socketed EPROM ECU chipped for 550's.

You really think it would cause a rich enviroemnt, I was thinking it would be a tad bit lean.

If with a 2G and a Socketed Eprom ECU its possible to run high 12's. I think I am going to take my GM-Maf and throw it off the biggest cliff in Canada, because for the last year I havent been able to tune with it properly.

 

[4gsx63]

So your friend ran 10psi on a 20G and trapped 113mph? Is his car FWD? What kind of magic boost guage does he runs? I want that boost gauge

 

[trixtert]

Yah he did a TDO5H-20G With an adjustable internal wastegate, he is using an Autometer Boost guage and no its a 1993 AWD

 

[andymoraitis]

Ooops, i forgot to mention he does have a socketed EPROM ECU chipped for 550's.

Well that kind of changes what I said earlier. If he's chipped for the 550's that's all well and good, but unless Nate or Jeff gave him a custom A/F map, he's still on the stock A/F ratio and that's pretty rich. Can he run 12's? Probably. He'll have to turn up the wick and see while watching for knock on the stock boost gauge.

 

[Kevin Jewer]

Is it also chipped for running the wrong MAS? This is the oldest trick in the book. The 550s need to be leaned out about 18%, and the 2g MAS reads about 15-25% leaner than the 1g (been a while since i looked at the numbers). It's not a perfect cancelation however, and even if it was, that would still leave you with crappy stock AFR targets in the 9s.

10 psi is actually going to provide a lot of airflow on a 2.3 liter. No magic. In fact a 20g on a stroker will be completely tapped out around 18-19 psi with typical setup (1g head, cams), for reference.

 

[andymoraitis]

The 550s need to be leaned out about 18%, and the 2g MAS reads about 15-25% leaner than the 1g (been a while since i looked at the numbers). It's not a perfect cancelation however, and even if it was, that would still leave you with crappy stock AFR targets in the 9s.

Good stuff Kevin. I should have considered the differences between MAS readings on the 1G and 2G's. Live and learn I guess!

 

[trixtert]

I know that the head is fully built with 272's 5angle valve job and OS Valves and some extensive port work. But you guys are saying that it is safe? It is a bit rich but it is safe

 

[Kevin Jewer]

It's impossible to be sure, but it should still be quite rich. Which probably contributes to the fact that he doesn't see any appreiable knock. If I were him I would keep watching knock as I upped the boost, and stop when it knocks or fuel cuts (it may not fuel cut, since the 2g MAS will be roughly the equivelent of reducing the airflow signal via AFR or similar for 550s). But all of the usual disclaimers apply.

 

[trixtert]

Thanks alot for the input guys, the reason I ask is that I would love to do a similar setup on my car, because tunning is a black art to me and Ive wasted way to much money and time with the MAF-T. And if I could splice in a 2G MAF and go to lets say 18, 19PSi (from my EVOIII 16G) I would be perfectly happy with that.

 

[Kevin Jewer]

A 2g MAS is ideal for an EVO16g. It reads up to 50 lbs/min, and that does does 42 lbs. I would still recomend having something to tune with though. DSMlink has built in presets for the 2g MAS in a 1g, and is the ideal way to go IMO. If that's out of reach, a 2g MAS with 550s lets you run an AFC without bollixing the airflow signal too much.

 

[trixtert]

Ok thanks for the advice, yah a DSM Link is out of my budget and also its a bit too complex for a novice tuner such as myself. But an SAFC-II and a 2G-Mas might just do the trick

 

[kelvinb]

get a megasquirt

 

[trixtert]

whats a mega squirt

 

[Kevin Jewer]

Might as well look it up

get a megasquirt

I'm not a big fan of 3 word replies with no punctuation that don't provide any reasoning behind your suggestion. It's not going to help anyone.

 

[GVR4592]

Ok thanks for the advice, yah a DSM Link is out of my budget and also its a bit too complex for a novice tuner such as myself. But an SAFC-II and a 2G-Mas might just do the trick

Dsmlink is no more complex than the SAFC. It's actually easier to use in my opinion, I hear ya on the tight budget though.