Full tune of 68HTA, KSTech 73 MAF, Racer X FMIC and DW750s

[ClimberDHexMods]

FWIW I passively only heard of leaning out on sidefeeds as well, and people switching to topfeeds and not complaining. Though the visual posted above is my wake-up to how serious it is...

[NSFW]

Maybe I'll have to see if the ID 1000 hype is for real.

[praedet]

So here is the question. If the engine is out already, would the switch to topfeed be worth it at that point to get rid of this phenomena? What parts are required to do that?

[NSFW]

I haven't done the swap but I'm sure you'd need injectors, TGVs, and fuel rails. Possibly also some odds-and-ends... like o-rings, if those don't come with the rails.

[ClimberDHexMods]

Mweiner did the swap. When I looked at the cost of doing it on mine, it's tgvs, rails, injectors, fuel pressure setup (hopefully the simple fpr), a possible adapter for the fpr, and extra hose. You can piece the whole thing together on your bench. If you're missing any tiny pieces, it will be obvious then. I also priced out Perrin v1 sidefeed rails used, and it was cheaper than the full swap. Then I sold the rails for cash lol. But if you can get the full topfeed setup off one of these numerous vehicle partouts or a junker somewhere else, that's the cheapest way I have found. There are also great deals on a setup including the sti intake manifold and tb, all bolted together already. Easy and cheap. Hope that helps somebody.

[NSFW]

Good point about the FPR. With the strut-tower-mounted FPR, I'd just get aftermarket rails and a bunch of hose. But on a car with the FPR integrated with the hard lines, then switching fuel rails might be more complicated.

[ClimberDHexMods]

Good point about the FPR. With the strut-tower-mounted FPR, I'd just get aftermarket rails and a bunch of hose. But on a car with the FPR integrated with the hard lines, then switching fuel rails might be more complicated.

 

There's a cheap aluminum adapter on ebay for this exact purpose, found it in the NASIOC parallel fuel rail mod threads

[Spec B]

Guys, I am not trying to derail this thread bu I have a very basic question about tuning injectors and the Maf table.

 

Assuming someone upgrades injectors and the intake at the same time, how or is it possible to properly tune the maf table? I am guessing you could get to your target afr by adjusting both the maf scale and the injector latency, but there would be no way to confirm that the maf g/sec (the one we all brag about) is accurate. Am I missing something?

 

Thankfully I have my maf tuned pretty close and I plan on upgrading fueling soon, but I was curious how it is handled when both injectors and intake are swapped out on the same day.

[yamie700]

LittleblueGT did you ever push the DW 650cc with the HTA68? I'm just curious if that size injector is enough to keep up with that turbo. I know you plan to run meth with it, but for 92 pump do you think 650cc are enough to max out the HTA68?

[testes1010]

92 pump do you think 650cc are enough to max out the HTA68?

 

No. My TD05H-20G ran my UR785cc injectors to mid-80 idc on 93 octane with ~11.3:1 AFRs. 0.85(85%) x 785 =667. The HTA68 should be more capable than my TD05H-20G.

[Infamous1]

 

Assuming someone upgrades injectors and the intake at the same time, how or is it possible to properly tune the maf table? I am guessing you could get to your target afr by adjusting both the maf scale and the injector latency, but there would be no way to confirm that the maf g/sec (the one we all brag about) is accurate. Am I missing something?

 

Thankfully I have my maf tuned pretty close and I plan on upgrading fueling soon, but I was curious how it is handled when both injectors and intake are swapped out on the same day.

It honestly isn't nearly as hard as some make it seem. Although not the best way to go about it, its nothing difficult. No matter how on target your MAF scaling is, I have found once you change injectors or even turbos it will need to be revisted.

[LittleBlueGT]

Guys, I am not trying to derail this thread bu I have a very basic question about tuning injectors and the Maf table.

 

Assuming someone upgrades injectors and the intake at the same time, how or is it possible to properly tune the maf table? I am guessing you could get to your target afr by adjusting both the maf scale and the injector latency, but there would be no way to confirm that the maf g/sec (the one we all brag about) is accurate. Am I missing something?

 

Thankfully I have my maf tuned pretty close and I plan on upgrading fueling soon, but I was curious how it is handled when both injectors and intake are swapped out on the same day.

 

If you have injectors that you know the flow value of, and you know the latencies, I would just plug those numbers in and tune the MAF from there.

 

You can always tweak latency a bit by checking the same MAFv but at different rpms, and see if it lines up with what AFR is called for in the map.

[LittleBlueGT]

LittleblueGT did you ever push the DW 650cc with the HTA68? I'm just curious if that size injector is enough to keep up with that turbo. I know you plan to run meth with it, but for 92 pump do you think 650cc are enough to max out the HTA68?

 

I did, but only on pump, and I had to dial back my timing soo much I think I was at the point where I was making less power on more airflow.

 

I was easily at 95% IDC at about 18 psi at red-line (maybe only 17 psi) at 10.8:1 AFR.

 

I didn't intend on running the boost very high w/o alky injection. WITH alk injection (<<< key point there) I was confident I would be able to run this turbo full out at 11.7 or 12:1 AFR, even at -30F.

 

I could run 338 g/s at 100% IDC at -37F with my AVO380 at 11.7:1 AFR w/ 450 cc.min of alky. This was the coldest I ever logged, and it only just touched 100% IDC at about 7000 rpm.

 

640s have almost 20% more fuel, so that means on the juice I should have been able to flow close to 400 g/s on a bigger turbo before running out of fuel.

 

Just think, if 537 cc/min of fuel can support 285 g/s of air at 11:1, then 640s can support about 340 g/s. With alky I was I was injecting about 450 cc/min of 50/50 mix. So 225cc/min of meth which is comparable to about 160 cc/min of gas. Then targeting 12.8:1 AFR vs 11:1 results in a 16% fuel usage saving. So for me, having 640 cc/min injectors allows me to have enough fuel for 16% more airflow, then I would w/o alky.

 

[Spec B]

Thanks guys...makes sense now. I always thought if you knew your Maf scaling was accurate, you simply adjusted the injector latency until it the afr matches up up with what it was with the stock injectors. I guess if you know the flow and the latency it is just as easy.

[mickeyd2005]

Thanks guys...makes sense now. I always thought if you knew your Maf scaling was accurate, you simply adjusted the injector latency until it the afr matches up up with what it was with the stock injectors. I guess if you know the flow and the latency it is just as easy.

 

 

Even if you don't know the latency, you can guess because you know how much MAF it takes to idle the car.

 

Also, the fueling is always uneven across the load-rpm table. In closed loop, you use the MP compensation table to adjust for those dips and spikes. In open loop, you use the OL fuel table to adjust. So, you can use these same compensation tables to adjust for inaccurate values.

 

Remember that fueling is a ratio. Even if the MAF is completely wrong, you can adjust the injectors and other tables to make the AFRs work out.

 

The only thing to worry about is that if the MAF is too far out of whack, the load values in the timing tables and any other load affected table will be wrong. So, you just need to be close.

 

I don't think this is something beginners want to attempt since they can get confused.

[Spec B]

Thanks MickeyD...what is MP comp table? In RR is it the target comp table under closed loop fueling?

[mickeyd2005]

Small dips and spikes in closed loop will be taken care of by the front O2 sensor. However, it doesn't respond fast enough for large spikes or dips. If you have a stock intake and resonator, it's usually close enough.

 

08LGTSPECB had some driveability issues caused by the large dips and spikes. I think he has intake, injectors, etc...

 

http://www.romraider.com/forum/topic4911-150.html

 

Airboy has a more convenient spreadsheet here:

 

http://www.romraider.com/forum/topic5483.html

 

I still prefer to use MAP instead of MRP.

[mickeyd2005]

I've tuned a couple of cars using the MRP compensation table. They all had FMIC, intake, and large injectors. It doesn't improve performance. It just eliminates the hesitation and jerkiness caused by the momentary lean spike (AFR 15-16) during closed loop when the front O2 sensor can't react fast enough.

 

From what I have seen, injectors result in a change to the MP compensation table as well as a short ram intake.

[Infamous1]

I've tuned a couple of cars using the MRP compensation table. They all had FMIC, intake, and large injectors. It doesn't improve performance. It just eliminates the hesitation and jerkiness caused by the momentary lean spike (AFR 15-16) during closed loop when the front O2 sensor can't react fast enough.

 

From what I have seen, injectors result in a change to the MP compensation table as well as a short ram intake.

Interesting

[LittleBlueGT]

I think I have the spreadsheet (pivot table one, not that I really understand that) from airboy figured out. I will be using it to tune the MRP load comp table is well.

 

The way I understand it is this:

 

-0 out the MRP load comp table

-tune injectors, then MAF

-then tweak MRP load comp table

 

Is that right?

[mickeyd2005]

Yeah. I use AFR learning to scale the 30 to 70 g/s range by adjusting AFR learning ranges. I think I spoke to you about that before.

 

And, I use a simplified version of my old spreadsheet to adjust below 30 g/s.

 

Get the MAF range as close as possible.

 

When you do this, use 1/2 the CL/OL delay. Don't zero out the CL/OL delay. You need the MP table to slightly overlap the OL range. You may need to rescale it FIRST. Take a look at 08LGTSPECB's table that I gave him. Notice that I extended the rpm range.

 

BTW, be careful if you are not at sealevel. The MP is table is based on manifold absolute pressure. It's just displayed witha -14.7 against it. If you are at sealevel, you have to keep this in mind. I think Airboy's spreadsheet accounts for it for you.

[LittleBlueGT]

Yeah. I use AFR learning to scale the 30 to 70 g/s range by adjusting AFR learning ranges. I think I spoke to you about that before.

 

And, I use a simplified version of my old spreadsheet to adjust below 30 g/s.

 

Get the MAF range as close as possible.

 

I actually just drive very consistently at a target AFR of 14.5:1, and then have CL disabled. IMO this allows for a smoother flow of data, and less variables given the slow refresh rate of our logger. I have never had a problem getting my MAF dialed in very accurately. At least my LVs always show extremely close in the B, C & D range (less then 1% off).

 

When you do this, use 1/2 the CL/OL delay. Don't zero out the CL/OL delay. You need the MP table to slightly overlap the OL range. You may need to rescale it FIRST. Take a look at 08LGTSPECB's table that I gave him. Notice that I extended the rpm range.

 

I know what you are saying, but I may try all of this tuning with the OEM O2 sensor in the DP (COBB). My Front O2 went again, and I suspect the location in the header (Perrin), so when I get the new one it goes in the DP. This will allow me to scale from 40-150 g/s much easier,..................I think.

 

BTW, be careful if you are not at sealevel. The MP is table is based on manifold absolute pressure. It's just displayed witha -14.7 against it. If you are at sealevel, you have to keep this in mind. I think Airboy's spreadsheet accounts for it for you.

 

Airboy's sheet does ask for atm pressure, so I think I will be OK.

 

I will be sure to post up relevant data when I get it.

 

 

 

On a different note, I should soon have my hands on a custom 73mm intake c/w heat shield!

[LittleBlueGT]

I just looked again at airboy's Engine Load Comp (MRP) spreadsheet.

 

I think I may do this all in OL as well, I just need to figure out what to change so that the sheet knows I am targeting something slightly richer then 14.7:1.

[LittleBlueGT]

Finally I am getting my stuff together.

 

I got my new DW740s, they scaled great, put in the flow value of 730 (from DW) and 10% more then stock latency. So far everything is within 2-3%! Also, it doesn't seem to be leaning out at high rpm (like the DW850s) did!

 

My new 73mm intake is on the way!

 

My new front O2 is in the DP, and seems to work very well from there. I still have some more testing to go, but it looks promising right now. I am considering scaling my intake with AFRs in the 11.7 range on pump fuel and Torco, all without breaking out the WB!

 

I tried the whole hybrid boost control w/ MBC, it worked well if you didn't have a big temp swing, but I was already seeing a 1.5 psi spread in 40 degree different temps (F), so for me it is out of the question.

 

This whole faze of my tuning is taking me forever (due to waiting for parts), but should soon be over.

 

FWIW in 2nd gear I hit 15 psi by 3100 rpm, 20 by 3500 rpm, and it isn't even that cold yet!

 

In 3rd gear I hit 20 psi by 2900 rpm!!!! Yippeeeee!!!! So I can hit an easy 330 wtq on pump, but only about 270 whp due to the super duper extremely crappy timing I have to run on our pump piss.

 

I am sooo looking forward to getting my alky back on and running some decent timing, and making some decent whp!

[NSFW]

With the MBC, did boost go up as it got colder, or down?