I just recently installed some NGK 55 IV spark plugs in the Hawk. Probably around 5K miles on them so far.

I've had the Granatelli MAF for a while now. On my one and only wideband session a few months ago I had a perfect 13:1 AFR on a car with Lid, filter, GMAF, spark plugs, plug wires, and FLPs. The fuel line was straight as an arrow and hugged the 13:1 mark the whole way. So I was pleased.

Are these two current mods going to work well with my D1SC? What are the best plugs and MAF for my blower?

Thanks,
BH

 

Stock MAF and TR6's

 

I'm running an SLP 85MM MAF, its working out just fine, got a 12:1 AFR through the whole range..I'm using TR6's... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

ok, clarify

Stock, unless you tune with a WB O2 for the best results.

You don't wanna play w/ the AF with boost. Get it right the first time <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

I will most definitely be spending a lot of time on the wideband dyno to get a very safe/reliable tune for the Hawk. But could you guys go into a little more detail why the TR6 is better than the TR55 and why the Stock and/or SLP MAF is better than my GMAF?

Thanks so much fellas,
BH

 

The plug will be colder, made for boost/nitrous..

Also some people have leaning out issues with the aftermarket MAF's, but like Harlan said, if you have a good tune (like I did) you can get around that.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by BIGBOS:
<strong> The plug will be colder, made for boost/nitrous..

Also some people have leaning out issues with the aftermarket MAF's, but like Harlan said, if you have a good tune (like I did) you can get around that.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Well I will definitely replace the plugs. Will tuning my GMAF be any tougher/easier than any other MAF? Will I still see the HP increase out if it after I'm done tuning? I mean if I'm not going to see any additional HP out of it I might as well sell it and either go with the stock MAF or if there is a better MAF out there, go with that. Just trying to utilize the best possible components without breaking the bank.

BH

 

The reason the GMAF is "suppose to" increase power is the same reason people port their MAF.

When you go to WOT and enter enrichment, you're basically fueling off of straight MAF readings. If you happen to have positive L-Trims they will get added in. The idea behind the GMAF or ported stock is to open up the measurement orifice, or to report slightly less air than is actually passing through the MAF. Since the PCM is not closed loop on A/F at WOT, you can lean the mixture by reporting less air. Leaner is meaner.

As a side effect, you read less engine load and the spark advance will increase slightly. Less load generally results in more advance with a stock tune.

Now when it comes to FI, you want to have good control on both A/F and advance. This comes w/ tuning. If you leave the GMAF in there, you'll basically end up tuning out the effect it is intended to cause.

W/ boost, you want to reduce the advance from the stock tune, and leave the A/F about the same as stock. You may lean it out some, but a stock MAF w/ boost will put you in the mid to high 11:1 area.

Get some cash for the GMAF, but the stocker back in, run a colder plug (TR6) drop about 2 degrees out of the stock advance curve and you should be pretty close on 7 or 8 psi.

But, a WB and a decent dyno will be the deciding factor.

The last thing you wanna do under boost is fool the PCM into leaning out the mixture and adding timing.

the stock metal MAF, not the 85mm, shouldn't really be a restriction until after the 600RWHP mark. And FWIW, a production 85mm MAF actually has less flow range for the availible PCM input range than the metal MAF.

I'm still pushing through a 3.5" MAF, yes it's a rescaled output range. But the orifice is not drastically different than the stocker.

just food for thought <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

happy boosting <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

Great post Harlan. That's exactly what I was trying to figure out.

Thanks for all the help BOS and Harlan. I'm slowly getting all the info together to put in a safe/reliable bad mother of a blower on the Hawk. It pains me to look at the blower each night and not put it on the car. But I figure it's better to take my time and get all the advise first, before breaking something and learning the hard way. LS1Tech, and more importantly, the FI section has been a great help so far.

Thanks,
BH

<small>[ January 31, 2003, 03:31 AM: Message edited by: Blown Hawk ]</small>