Dry Tuning Questions

[Beer99C5]

I am going to be expiermenting in Nov w/ COS 5 and the VE multiplier, and I was looking overall at other items of interest and was wondering about the following:

I am tuning a 100 Dry Shot on a H/C car
...
B0120 RPM Thresehold for Airflow Calc...Being its a dry shot and MAF Dependant, my Dry is coming on @ 2800. Seems to me I want MAF calculation (its what feeds the Dry Fuel) when the dry shot is enabled.

MAF tuning...ok so we tune the MAF best we can, I got it to 1% prior to the H/C...now though with the Nitrous, (Flow a function of pressure...) and tuning the MAF under Nitrous conditions seems like a different animal because you have bottle pressure a factor...Any Suggestions on MAF tuning while spraying Nitrous, or just use the VE multiplier with target bottle pressures?

B0109 Blend IAT w/ ECT...seems to me "No" is the better pic to try and take advantage of the cooling effect of the nitrous on the charge, "Yes" Blending will skew it??

[Kevin Doe]

Any results here? I'm planning no doing a dry shot as well, except in speed density mode. If they ever come out with a COS5 for the 1MB PCMs (2004 GTO).

[Beer99C5]

I am doing a test/tune session on the dyno end of Dec I will write up my results. I plan on the dry @2800 RPM, the major problem is I want to use the safety's built into my Trick Performance Nitrous gauge and set them up for 10-12 AFR, anything out of that it will shut down the nitrous system. I had the pin to ground wired to a toggle, but now I am going to wire it to the Dry Arm so it cannot be forgotten. The trick is going to be getting the AFR into the safety range prior to 2800 else the nitrous will activate late.

[eurospec1]

Any results here? I'm planning no doing a dry shot as well, except in speed density mode. If they ever come out with a COS5 for the 1MB PCMs (2004 GTO).

You lost me here, if your running speed density, then your not running a MAF, how are you gonna use a dry kit?

[Kevin Doe]

YOU, lost me with that question. Why could I not run a dry kit in speed density?

With COS5, I should be able to setup the EFILive to add fuel, and reduce timing when an external trigger is sensed. That trigger will be when the nitrous is triggered.

[ScarabEpic22]

I think what he meant was that dry N2O kits are placed pre-MAF so when the N2O goes through the MAF the PCM senses this change in temp and can adjust fueling.

You are talking about setting EFILive up so that when you hit a switch the fueling is already set specifically for N2O, basically hitting a switch vs letting the MAF make the changes for you.

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Am I close guys? Hope I am! :)

[joecar]

The MAF senses increased "flow" which causes the PCM to add fuel.

[ScarabEpic22]

The MAF senses increased "flow" which causes the PCM to add fuel.

Thats the simple answer I was aiming for, thanks for reading my mind!:cheers:

[joecar]

:cheers:

Now if I could only read my Mrs' mind... ;)

[eurospec1]

YOU, lost me with that question. Why could I not run a dry kit in speed density?

With COS5, I should be able to setup the EFILive to add fuel, and reduce timing when an external trigger is sensed. That trigger will be when the nitrous is triggered.


While i see how that could work for a dry kit, its generally used for wet kits (at least in my experience) becouse with wet kits there is no way to control fuel or timing,

Dry kits fire the nitrous in front of the MAF, when the MAF see's the nitrous it senses it as extra air, so it adds fuel to compensate, so if your in speed density with the maf turned off, it would not work

[Kevin Doe]

Using COS5, there are fueling modifiers you can use when an external trigger is sensed.

[eurospec1]

Using COS5, there are fueling modifiers you can use when an external trigger is sensed.

I know, ive set up quite a few of them ;)

[Kevin Doe]

With that said, its not necessary for the maf to do anything for a dry shot, and thats why it will work on a speed density setup.

[eurospec1]

With that said, its not necessary for the maf to do anything for a dry shot, and thats why it will work on a speed density setup.

I understand that, i suppose my question then is, why? Dry shots are generally used due to low price, and ease of install becouse they require little if any tuning, if your gonna set up the COS5 nitrous controls, why not run a wet kit?

[Kevin Doe]

I feel that a dry kit is better for these reasons.

1. The intake manifold was designed for air (not fuel). The placement of the dry nozzles is much less critical than compared with a wet kit.

2. This is kinda related to 1. Distrubution. Fuel will be equally distrubuted to each cylinder when its comming form the injectors. The nitrous from the dry nozzle will be equally distrubuted as well. With a wet kit, the nitrous will be better distributed than the fuel will. This could cause issues with the AFR being off from cylinder to cylinder. With a dry kit, you are still only flowing gasses (air and nitrous) through the intake manifold, just as designed for.

3. Less cost. There is one less solenoid, less fittings, less plumbing. No fuel jets to buy, etc.

4. Better control. I feel that I will have better control over the AFR by using the PCM to control the fuel. Not only that, but I feel that I will have easier control as well. Changing a few things in the tune will be easier than changing jets.

5. Better fuel rail pressure distrubution. By pulling fuel from the end of the rail (as commonly done) you are bleeding flow off of one bank's fuel rail, this could cause an uneven fueling through the injectors. With a dry kit, this is not an issue.

6. Cleaner look. I will be albe to conceal the solenoids and lines much easier. I don't much care about being 100% hidden, but I like everything to look stock, and I think that a dry kit will be eaiser in that aspect to keep looking stock.

All the reasons I listed are very minor. In practice most of those reasons are negligable and can just be ignored. I like things to be designed as good as possible. I'm an engineer, so I like the design to be right, even though a slightly off design setup would work, I like it to be perfect or close to it in the design aspect. Its mainly personal preference, but I really do think that for my application I would be better served with a dry kit.

[brokenfly]

i need to figure out the correct doses of fuel to n2o...

i could then just convert my single nozzle wet kit into a 2 stage dry direct port...

a few times i purposely left the n2o pressure off line as i ran it wot to see just how rich the 100 shot fuel jet was...(10.2)

i guess i could just log fuel jets to see what i end up with and go from there...:cheers: :bash: :beer:

[Beer99C5]

2. This is kinda related to 1. Distrubution. Fuel will be equally distrubuted to each cylinder when its comming form the injectors. The nitrous from the dry nozzle will be equally distrubuted as well. With a wet kit, the nitrous will be better distributed than the fuel will. This could cause issues with the AFR being off from cylinder to cylinder. With a dry kit, you are still only flowing gasses (air and nitrous) through the intake manifold, just as designed for.

5. Better fuel rail pressure distrubution. By pulling fuel from the end of the rail (as commonly done) you are bleeding flow off of one bank's fuel rail, this could cause an uneven fueling through the injectors. With a dry kit, this is not an issue.


I was kind of shocked when I compared a 50 dry to a 50 wet shot with my H/C. The dry a slight FP loss and recovery (low mid 50's) but no drop in HP. The wet FP dropped to mid 40's PSI for less than a second, it recovered, but on it left an Obvious Dip in the HP on the dyno, the HP increased again after recovery, but you can see the effects it had.

Dry was 2800 RPM Wet 4000 RPM

http://www.retrorelics.net/jim/Boards/Corvette/DynoHCNitrous.jpg

[Kevin Doe]

Beer, VERY good data. It looks like your data agrees with my theories. But, the differnece could be caused by the difference in when you turn it on.

How are you fueling when you are doing the dry shot? Are you doing all the fueling via the COS5 features in the PCM, or are you relying on the MAF to pick up on the additional airflow, and just trimming it with the COS5 features in the PCM?

[Beer99C5]

Currently the MAF. Doing a good COS5 session on the dyno w/i next few weeks. I get paroled for Xmas next Wednesday. :beer:

[oztracktuning]

My new setup with a dry system just did an accidental 10.976/123.22mph launching in 2nd gear.

It uses the 5177 NOS dry twin nozzle system, FJO mini and EFILive COS5. 100 shot seems to want about 15% more fuel and 3 deg less timing. The FJO sends an earth to the PCM to activate the extra Nitrous tables at the same time as it sends an earth to the solenoids to activate the window. I have the dual stage capability of the FJO set to identical windows (but the PCM one is 100% straight away) , i have the nitrous solenoids ramping from 0 to 100% from 4000rpm to 5000rpm, spraying on gear changes etc.

The car did 1.510/11.125/121mph with a 60 shot and would have run 10.8-/124- on 100. Its race weight with driver was 3644lb (1653kg).

[joecar]

Steve, if you have any logs we would like to see them. :cheers:

[Beer99C5]

Steve, if you have any logs we would like to see them. :cheers:

Me too :cheers:

[oztracktuning]

PM me your email addresses.

[VYSSLS1]

Steve,

Almost completed the latest NOS install, 6 vehicles in total minimum shot 150hp after being on the phone to Paul and Ross, absolute ledgends:rockon: , we have now a NOS multiplier high enough for the 250hp dry shot, the vehicle isnt completed yet, as the new clutch let go on the dyno. I will keep you posted steve on the overall power output, so far torque figure is 1085 engine tq @ 4200rpm and 415rwkw @4200rpm. Expected power figure will be approx 480rwkw@6000rpm with peak torque 1100nm's @ 5000rpm.

[oztracktuning]

Hi Brad
I am supporting a car with goodies soon that wants to run a 300 shot in a forged engine (wet). It should be good for a sub10s pass.

[WHYTRYZ06]

How do you determin how much to ad to the ve multiplier table in cos5 for say a 2 stage 175 dry shot???

[Beer99C5]

Spray the shot and enter the data into the spreadsheet, then modify the VE multiplier, then log again and walk it in to where you want it, by entering your new log info.

OZ has used it, I am using it mid Mayish

http://www.retrorelics.net/jim/Boards/EFILive/EQ%20for%20Nitrous9703DLFeb08.xls

[oztracktuning]

It might be a car by car thing. The amount thats needed my car can just get away with a 150 shot dry. But its fuel pressure drops from 58psi to 40psi !!!

The enrichment amount for it is 30% ie 1.300 - but if the pressure stayed steady at 58psi then maybe it would only need a smaller amount of enrichment because my values are inflated by the dropping fuel pressure.