IroczInOz

Been looking all over the forum for some information. Found the posts about the increase in pump shot. Also found Trax's tables that he used in his miniram. Below is the following Cam that is in the car. We are running the 730 MAP set-up. It was running pig rich at idle. We had the fuel pressure too high and brought it down. We took a heap out of the VE values where it idles between 65-70kpa which made it better. But there is a big dip in the VE table where we took out the values. Now we took it for a drive and it went pretty good, except for a pop sound coming from the intake at around 2500 rpm. It does get this intake backfire always at the same spot in the RPM band. Once over 3000rpm and you hammer it, it will not make this popping sound.

I took Trax's advice on raising the pump shot and basically used his values that he used on his set-up. But even with those new values in it still made that pop sound. The Base timing is set at 6deg, fuel pressure around the 45psi mark.

Duration at 0.006" Lift: Intake: 292° Exhaust: 300°
Duration at 0.050" Lift: Intake: 232° Exhaust: 234°
Lift at Cam: Intake: 0.325" Exhaust: 0.325"
Lift at Valve: Intake: 0.488" Exhaust: 0.488"
Timing at 0.050" lift: Open Close
Intake: 10° BTDC 42° ABDC
Exhaust: 47° BBDC 7° ATDC
Centerlines: Lobe Separation - 108° Intake Centerline - 106°

The O2 sensor is stuffed though as it is playing funny buggers. So a new one has been ordered. I think it was a Bosch unit and going by what I have read they seem to have a bad reputation.

Now should I raise the pump shot even more to try and get rid of this popping?

SAUJP bin is in use and we even tried the spark table that Trax used except we made it more tame and not run so much timing. Max of 42 deg in the spark advance.

The VE values will need to be adjusted quite a bit I imagine up high as this is where the MINIRAM will shine... Except at the idle points it is very very lose maybe because of the big cam and overlap. Also the values might be totally different once we get the new heated o2 sensor put in.

Any other suggestions or tips for this set-up?

Grim Reaper

Are you able to check out the ARAP $6E bin settings? I used that as a base when I tuned a buddy's car (Miniram, AFRs, solid roller cam 246/252 @ .050, 3600 rpm stall).

The major changes I had to make to the ARAP bin whle tuning were in the MAF Scalar Tables. I never had to play with the AE settings which are similar to those used in the SD setup. I did some adjustments to the spark table - but nothing that would cause the popping problem.

I find there are advantages to reviewing both MAF & SD setups as there is a lot more common tuning than most people think (once you ignore the MAF Scalar vs VE Tables).

IroczInOz

I do have the ARAP BIN which I can look at. So you think maybe try the ARAP spark settings and see how it goes with those? It just seems to have that hesitation around the 2500rpm mark. But after that it seems to pull real well. Just got to fix that stumble and then fine tune the VE tables and play around with the spark table.

Just had a look the ARAP BIN and the spark table looks very similar to the as the SAUJP one that TRAX was probably using in his miniram.

Grim Reaper

I found some of the "max values" for the ARAP spark table a bit high and toned them back. But I did retain it's agressive curve - just gave the top-end a bit of a haircut.

As for the SAUJP, it may be that Traxion/Tim used the ARAP's spark table as a blueprint when he developed it. I will add that Tim's Miniram setup was very similar to my buddy's (Miniram, AFRs, large cams) - so the similar spark table make sense.

IroczInOz

Yeah I also trimmed down the top part of the ARAP. The car pulled great above 3000rpm I'd say. It was just before the stall convertor kicks in that it has hesitation. I think it just might need a little more fuel in that area, so will raise the VE values a bit.

The O2 sensor was stuffed in the car so maybe that may also solve some issues. Then we might get some reliable data we can use to tune the VE table. The car was running very rich before we got the fuel down and running well on Idle. So it probably killed the O2 sensor. I also copied Tim's Pump shot values into SAUJP. Would you happen to have a BIN of that mates car you tuned I can look at and compare?

If not no worries but looks like I have been doing the same as you. With the VE values did you have to edit them much for the larger cam up high in the RPM range?

89vette

I used to fight the same thing with the Miniram and and I ditched if for the Super Ram and the problem went away. The problem I had was an increased pump shot would make the INT plummet and the hesitation would be delayed. Then I started messing with AE decay to no avail. There is a thread located somehwere in the archives that shows a place in the $8D code where you can adjust the reaction time where AE fuel kicks in. In other words it shortens the time between the time the throttle moves or MAP changes so AE fuel is added earlier. I'll see if I can find it but I want to say it was at least three years ago.

89vette

Here is the thread
https://www.thirdgen.org/forums/diy-...e-fueling.html

Grim Reaper

I do think that if people made their SD bin look more like the ARAP bin for it's crucial items like spark tables, P/E, pump shot, dfco etc that much of the "popping" issue that people claim to have with the Miniram (and a large cam) will go away.

I personally have a Miniram and I would never consider a swap over to the SuperRam. Maybe the Holley StealthRam but never the SuperRam. My goal is to simplify the R&R - not make it more complex.

89vette

Do you know this for sure or is it just a hunch? I had other reasons for swapping out the miniram. I'm just starting to tune the Single plane efi intake that I had made that fits under the stock hood (89 vette). It has an intake elbow that bolts where the carburator would go. I have a slight hesitation when I goose the gas and sometimes get the pop. My hunch is that the short runners fill the cyliders faster than the long runner super ram OR it could be the smaller plenum.

Also, how do you mirror the PE tables when one uses MAP and one uses VE? I don't know it is that simple.