wwnf

iTrader: (1)

I've determined that I need a fuel system upgrade to do any further WOT tuning so I figured I'd do some cruise tuning so that I can get better fuel economy.

Before I installed the Holley HP main body I had a Proform main body but I got lazy with changing gaskets and fuel bowl screw gaskets and I stripped out the threads in the main body trying to stop a leak. I just had to learn that lesson the hard way.

So I figured this would be a good time to switch over to the Holley HP main body since the Proform casting did not line up well with my throttle plate. It was off by 1/16th of an inch and created a lip.

Now after I installed the main body and set both throttle blades baselined with transfer slot looking like a square, idles 800-900rpm in gear 14.0 AFR, my cruise went way rich again. Before the HP main body I was in the 13's while cruising. This puzzled me but I can only think that maybe the HP main body gets a better signal. The air bleeds are all the same except for the idle air bleeds, the HP came with 75's and the Proform had 73's.

After the HP main body install I was getting an AFR around 10.5 with 73 main jets and kept jetting down until I ran out of smaller jets at 64's and now getting 11.5 AFR. My rpms are around 2600 when I"m cruising ~60mph, the car has 700r4 and 4.11 rear. So after running out of jets to try I remember reading this article, Old school meets new school, where they delayed the mains by increasing the size of the main high speed air bleeds. So off I go drilling out a couple spare air bleeds, install, test and repeat many times until I got to the point I just tried running with no main high speed air bleeds. Does not seem to delay the mains enough for my engine. So now I'm running no main high speed air bleeds and 64 main jets and I get the following AFR.

RPM AFR
2200 14.0
2300 13.5
2400 13.0
2500 12.5
2600 11.5

Also I watched my vacuum gauge and observed the following.

Vacuum in AFR
16-17 11.5
18 12.5
19 13.0-13.5
20 14.0

I pull about 16-17 vacuum when cruising the same flat road at consistent speed. I can let up just slightly to increase the vacuum and get better AFR but the car slows down, =).

I guess I'm looking for any kind of help to delay my mains or any ideas. I can only think of a couple, change rear to 3.42-3.73 range or get smaller jets and remember to drill out PVCR's for WOT. =)

Thanks

Joe

wwnf

iTrader: (1)

I guess I should have reduced the size of my IFR's first, I'll try that next.

rx7speed

maybe a smaller main/idle jet?

five7kid

iTrader: (14)

I'm thinking a power valve problem. Like it's blown, or isn't getting the vacuum signal.

wwnf

iTrader: (1)

Is it possible that I put the throttle plate to main body gasket upside down and covered up the holes that lead to the PV well?

wwnf

iTrader: (1)

I took the main metering block off (11180) and used some numbered drill bits to check the size of the IFR's and a #53 is the biggest I can fit. I looked it up and that bit is around 0.0595", seems a little large to me.

xpndbl3

iTrader: (5)

what are you using to tune with? a wide band or just a A/F guage and regular old o2 sensor?

wwnf

iTrader: (1)

Innovate LM-2 wideband

xpndbl3

iTrader: (5)

i know it's off topic but what is your opinion on the quality of that setup?

head

iTrader: (2)

Also sorta off topic; whats the difference/ benefit between wideband and regular a/f gauge ???

wwnf

iTrader: (1)

Five7kid was right, the PV wasn't getting any vacuum because I got the directions backwards (not sure how) and installed the main body backwards. And when you install the main body backwards, the PV well holes don't line up with the throttle plate holes.

Another moment.

I'll resume tuning from scratch again this weekend.

wwnf

iTrader: (1)

Are you asking about the Holley HP main body? It deffinately matches up with the throttle plate better but the quality of the cast on the top side is not as smooth as the ProForm. The bores on the Holley have a casting lip on the top side near the boosters, not sure if that makes a difference or not. You have to look up from the bottom to see it. Where as with the ProForm you looked down from the top and could see the lip of the throttle plate.

xpndbl3

iTrader: (5)

no the quality of the wide band tuning equipment and ease of use, etc.

rx7speed

plain jane o2 is more or less centered around stoich of 14.7 it can really only accuratly read something like 14.4-15.0 or so give or take a few tenths. it only has a voltage range of 1v though it is really only usefull from about .3-.8 or so give or take again. really only usefully somewhat for a cruise standpoint as it's whole intention is to see if your driving in a fuel efficient part of the a/f mixture other then that it mainly just reads rich /lean and that's it

the wideband uses a 0-5v signal and generally are good from about about 10-17/18 a/f ratio. this way you can tune leaner a little more accurate for cruise and also tune for the power band if you wanted to.

wwnf

iTrader: (1)

This is my first wideband and I chose the LM-2 so that I could get RPM and other sensors recorded. The feature I like the most is you don't need to drag a laptop with you. The LM-1 records up to 44 minutes of data and when your ready, just plug the box into your computer and download your logs with the LogWorks software. You can also still hook it up to a laptop if you wish to view more data while you're recording or record more than 44 minutes.

Very easy to setup and use. Plug in sensor and unit, calibration is automatic the first time ( sensor must be in open air ). Next, install sensor in car, run sensor cable to unit. Start car and power unit up. Withing 30-60 seconds the sensor will heat up and start displaying current AFR. Ready to go.

While your recording the current AFR displays on the screen and when you hit the record button it starts a new session. This is a nice feature so you can break up your recording sessions and be able to sort them out later.

The unit requires a 9volt battery to transfer data but it will run off the car battery when you have it plugged in. The o2 sensor has a heavy duty weather pack plug and lots of cable to reach the left or right side of your car. The unit just plugs into your lighter/power socket.

The unit is about 8" tall, 5" wide and about 1.5" deep. Case is not exactly a well finished product but as long as it works, right? Sometimes when I plug in the connections don't always feel solid. I've read where others had to re-solder some of their connections. I'm always careful with it and believe I should not have any of those problems for some time.

I think the case/connections could use a little more refinement, especially for $400, but I'm happy. It would be nice if the unit were smaller so that you could mount it somewhere when your not tuning. Anytime you have the sensor installed you can't run the car without the unit for more than 10 minutes or you risk clogging the sensor.

head

iTrader: (2)

For both replies !!!

wwnf

iTrader: (1)

I didn't need to delay my mains or reduce my IFR's. I measured my IFR's incorrectly and they are actually 0.031" so I just proceeded with the stock 73 main jets and ended up with a 67 jet to get AFR's in the 14's during cruise.

Next I'm going to try vent tube extensions to see if they help with my WOT. I will have to open up my PVCR's since they were too small for the 73 jets.

five7kid

iTrader: (14)

What happens when you ask it for power?

Sounds too screwy to have to go down that far in primary jets.

wwnf

iTrader: (1)

I made some vent tube extensions and tried them out today. This was the only mod I made and everything went way rich, could not even drive the car it was flooding so bad. I thought the vent extensions would only affect my fuel at boost levels but I guess I was wrong. I'm running a low profile carb hat and the vent tubes are pretty close to it so I made new ones out of 5/16 brake line and ran them upstream near the entry of the carb hat to get them out of the turbulent air. I'm running a surge valve so I'm a little confused how this made a huge difference all around. The car was idling so rich it was smoking, like 10 AFR.

Since I didn't have a fuel problem with the primaries I'm going to try the extension just on the secondaries tomorrow. Might have to read that other turbo forum for more information too.

wwnf

iTrader: (1)

Through second gear at WOT I'm getting 10.0-10.5 AFR. Currently 0.0625 PVCR's and 67 Primary, 99 Secondary jets. The plan is to tune the primaries only and drill out the PVCR's until I hit mid 11's. Then hook secondary back up and jet down to the same mid 11's ( hopefully the plan is a correct one ).

On part throttle approaching 10" vacuum it starts to go lean so I'm thinking of bumping my PV up to a 10.5 from a 6.5.

I have yet to wind out 3rd gear. Sometime this week I'll try it out and see if it still leans out on the top end of 3rd. So far the Holley main body ( installed correctly ) has been working much better than the ProForm.

Also I gave up on the vent tube extensions, everything just went way rich, I don't think I need them with the Holley main body. Maybe only Mustangs need them, =).