tecart

Just so i understand the proper operation of the arm1 and arc2,is this common with those who run the huntley kit maf #4 with arc2 and arm1? When i start to slow down fast from any speed and i press the clutch in, the arm 1 will go to red then totally off for a few seconds and with this the rpms drop too; considerably below 900 rpm's(somewhere like 600-700), then the motor feels like the fuel is temporarially shut off, also my oil pressure drops to 1 on the gage. This is a big concern, is it due to the arm1 or arc2, also if i release the clutch back out, all above problems go away, is this due to my arc2 being way off on its settings? its still having some tuning done as i write this and i may be overtaxing this issue but i just want to be sure to check all causes from this sudden loss of power. I really notice it if I slow down from say 80 to 0 and i keep the clutch in a long time the problems happen the worst. The problems never happened before the arc2/arm1/maf#4 install and if i drive slowly and stop slow instead of quick the problem wont happen ever. If you know what is going on here please let me know asap, my hunch is that everthing is wired perfectly, and have good grounds, but the arc2 is way off on its settings. I currently have it set at low 11:30, mid 2:00, high 3:00, accel 1:30 and I know this is really rich setup but it seems to be the only way to get a good idle and also it is the only way to stay out of the red area on the arm1 during full throttle accel.(I need lots of fuel for the turbo at full accel) I ran the autothority k29 chips but they were way too rich(lots of smoke) in the lower roms but fine upon full boost so i change to the k27 chips which gave no smoke at any speed. Im sure my settings will be different from most but i run a k29#8 and 3 bar fixed regulator with stock injectors with big fuel pump, should i change the regulator so my arc2 settings will then change to the norm of everyone else? I was told this was what i need to do and then the fuel would be easier to adjust instead of the fixed 3 bar unit. I also am running the dme rotory position switch 1 click from stock to give +3% extra fuel and 0 timing change. But in the end with all proper final tuning being done, is it possible when completed to achieve and expect perfect downshifting without the arm1 going blank and the rpms dropping below 800 and the car jerking a bit from the temporary second of fuel cutoff? Again im not concerned with the kits that dont use my setup so if you can shed your experiences id really appreciate it. P.S. My final guess on the problem is the arc2 is way off on its settings (and that fix includes the adj. regulator instead of a fixed 3 bar unit).The car will then be faster and some of the rpm dropping will cease but the arm1 will still die for brief moments with the fuel still cutting out brief as it may be as i "clutch in" while braking. Can the kit operate with none of my described problems once its perfectly tuned?

John Anderson

Try these settings:

LOW= 11:30
MID= 2:30
HIGH= 9:00
ACCEL= 1:00

Most of your settings are correct, you have the high cranked up there a bit. On a note, this has been a problem with the HR #4 MAF since its introduction. MOst have these symptoms you describe, and for some reason, a very few lucky people are not experiencing this. Do what I did, and replace that big #4 sensor with a #3 sensor. You'l clear right up. I still made over 400hp and 500ftlbs with the smaller sensor. When at aHR, I worked closley with a customer on this issue and ended up sending a couple prototypes to him to try and figure this out. The smaller sensor was the answere. THe proble is air velocity over the hot wire, the larger sensor just does not have the velocity at low rev's to keep the idle clean. The smaller sensor does very well at the low rpm management. Our kits at SFR all use the smller sensor, you can see our dyno results on our web site.

So, call HR, or you can call us and we will be glad to upgrade your kit to ours. Alot of HR users have done this and are very happy. Ian, also on this board just posted a topic covering your same problems. He called me and I told him the same thing...he had his mechanic make a kit that mocked ours, and the problem is gone, he is very happy now :-)

Hope this helps.

IanM

Yes indeed.

David Floyd

John,

What is involved in the upgrade from HR #4 maf to a SFR maf, is it a complete system change? price?

I have HR #4 maf, #2 Garrett,HR chips, 52lb injectors,Tial wastegate, adj fuel reg, test pipe, monster blow off, SFR fuel lines and SFR intercooler duct.

My problem is black smoke under hard acceleration which clear up on top end( my car is white and the back end has black soot all over)

I have talked with Derrek and you while you were at HR and have tried adjusting the arc 2 many ways but can't clear the smoke.

I am ready to change parts CHIPS? MAF? to clear this up.

Let me say this, HR and SFR have both treated me well and since I bought the system used, HR has stood behind there lifetime transferable support, but if there is some sort of problem with the #4 maf, I would like to solve it.

Thanks

Perry 951

I initally bought the Stage 1 kit. Is this the smaller diameter sensor, or did Huntley use all the same ones? (man.. I hope I lucked out) Mine also smoked a decent amount in the midrange. Good low, good high, little thick in the mid. I also tried pretty much every setting on the ARC 2, and got it close.

Reason I asked is because I had planned on getting your MAF pipes and use my sensor, (you knew that) since they are pretty much the same sensor.

DanD

Perry,
I bought Huntleys stage 1 MAF as well. I remember a conversation with Derek about upgrading to stage III with new pipes. I happened to find someone who made their own stage III pipe and bought it used (along with the straight intercooler pipes). I consider myself to be running a stage III now.
The stage IV is made for the 'big' turbos it's definatly bigger and more problematic.

DanD

DanD

Tecart,
I would talk to Derek about trading for a Stage I/III MAF sensor. It would be a 15 minute swapping it for the IV. You would probably use almost everything else the same. (hoses might be smaller/bigger).
Maybe Speedforce can do the same thing.
Unless you're in a quest for more HP that is..
DanD

Danno

Hmmm, strange... I haven't had any problems with using the Huntley MAF-4/Stg-2 turbo combination. Yes, it initially did smoke a lot upon initially flooring it and in the mid-range. But got that cleaned up with dyno runs, tweaking the ARC2, and burning custom chips. I had a mid-range that was WAY too rich at 10:1 or so, yet the high-end was getting leaner than 12.5:1.

Anyway, that's finely tuned now and I'm not letting ANYONE touch my settings. I also don't have the stumbling dying idle that a lot of people had as well. Maybe Huntley didn't ship me a MAF-4 kit after all...???

tecart

please, if you got a huntley stage#4 maf kit with the arc2, drive the car fast from 20 to 60 then press the clutch in and keep it in and see if: #1 the rpms fall below 900,#2 see if the arm1 lights totally go out,#3 the fuel feels like it has shut down and the engine isnt running, #4 the oil pressure gage falls way down towards the 1 mark, if you do this test, make sure the car has warmed up, and do the test by speeding up from 20 to 60 fast and try it be slowing down from 60 fast, just remember to hold the clutch pedal in far at least 4 seconds to test this fully. I want to know if it happens to everyone, again if you didnt look at the 951 email posts i made, i got perfect idle and perfect vaccume and the problems only happens when lots of air enters the maf kit and you depress the clutch for shifting and keep it in, my throttle position sensor,idle stabilizer,o2 sensor are all new, and it only happened since the kit was put on, also i had this kit 3 years ago and it did the same thing so i sent it back, then i had all my hoses, and tubes replaced with a new DME and KLR too, and reordered it again only to get the same issue, again im still doing tuning this week to try to get it better so im not saying it wont be perfect, but i have some doubts, anyhow derrick has stood behind his kit and already told me if it dont get better hed replace it with the maf#3 sensor for free, so thanks if your concerned. But boy the #4 kit is huge, nice looking, and sucks lots of air in for my k29 turbo... respond asap if you do the tests, thanks for all who respond, im getting desperate to fix this issue

IanM

Hi Danno,

I remember looking at your "RacerX" website when I was installing my big turbo. From your pictures, your Stage 4 MAF looks exactly like my Stage 3 MAF (before I cut it up and moved the sensor to where it should be!) On the Huntley website, the Stage 4 MAF has a bend after the air filter with bolts holding it onto the next section of pipe, yours just slips on with purosil hose like mine. Perhaps yours is really a Stage 3? Regarding the bucking problem, the fact that you don't have the problem might also be due to the size of your turbo. Even though mine is also a "Stage 2", it's got a MASSIVE cold-side housing and a full 3" inlet. In fact, I'm still not convinced that I don't have a Stage 3 turbo. Perhaps your Stage 2 doesn't create as much turbulence within your intake tract to screw up your MAF sensor signal. BTW, what ARC2 setting do you use?

John Anderson

Hi everyone, it seems to be a constant, I mean the issues with the larger HR #4 maf kit. This is my story:

I had the stage 4 HR kit, as like many of you, I had the same stumbling, over rich in the wrong areas as you. Mainly, going up a slight grade, gently pressing the throttle, I would go over rich, then buck. Same thing on heavy acceleration and easy let off on the throttle, bucking, lots of it. It made the car no fun to drive.

Its caused by a couple things, turbo inlet size, and the vortex (swirling air) from the inlet, side stepping the sampling tube in the maf kit.

I was a bit hesitant on reducing the #4 sensor, to the #3 sensor (HR sizes), but due to the consensus of many tuner shops, that told me over and over again that the placement of the sensor was bad in the kit, and the sensor was way overkill...producing low air velocity over the hotwire, I decided to take the plung and DOWNGRADE to the smaller sensor (the sensor we at SFR sell in all our kits). Guess what, HP loss was hard to prove, meaning it was basically not an issue. The driveability increased ten fold! I was using the SFR smaller sensor when I pulled 415HP and 515FTLBS at the wheels! The car was crisp and fun to drive, although I had to get over the feeling and habits of driving with those issues!

In response to this thread, SFR will ugrade all HR #4 MAF kits to our kit, eliminating the issues. We will charge 375.00. YOu keep your electronics, all you need to do is install our plumbing before the turbo. The upgrade comes with all new purocil, hose clamps, stainless plumbling and filter.

We are also running a special on our level one turbo. This is the same turbo some tuners call there stage two. With this turbo upgrade, you can specify the turbine housing size, compressor trim etc etc...you just tell us what you want. No extra cost, the turbo will be on special for 849,00! This turbo will support 400HP on a properly equiped car!

So, 375 to upgrade your MAF kits and get rid of the drivning issue, and 849.00 for a custom brand new turbo :-)

Take Care!

Danno

Ian, you know, I never even checked up on what Huntley sent me! I assumed since I paid for a MAF-4 kit, that I got sent one. When it came in, I was so excited I threw it on overnight and didn't bother to see which version I had.

Anyway, here's a photo of the sizing if anyone can confirm the dimensions for me, thanks :

• MAF manifold inlet: 2.75" ID
• MAF sensor inlet: 3.75"
• MAF sensor outlet: 3.375"

As for the turbo, I bought my Stg-2 ball-bearing turbo used and he said it was a Stg-2. The inlet is 2.75" though, so I think you must have one of the later Stg-2 turbos. John Anderson mentioned that they experimented with some 3" inlet ones. So they very well could have just used the compressor from the Stg-3 turbo. Wanna swap?

IanM

Danno,

Next time I take the intercooler pipes and MAF apart I'll definitely measure those sizes, and let you know how they compare to yours. It does look though like your MAF sensor has bigger inlet and outlet dimensions than mine, so it probably is a Stage 4. Perhaps someone else on this thread has already measured the inlet and outlet dimensions of their MAF sensor, whether it be a Stage 3 or 4? It is interesting about my turbo. It was such a pain to file/grind/squeeze into the car, I couldn't imagine fitting anything bigger without a custom intake manifold. I think you're right about the compressor housing. I talked to John Anderson yesterday, and he figures I've got a Garrett T04B with just a bigger compressor housing.

John Anderson

Danno!

THats a stage Four, you got what you paid for :-)No worries there. By the way Dan, Tim and I are discussing having a So Cal Pizza meet down here at the dyno shop. When we nail the date, I hope you come down, I'll make the drive worth your while and let you ride the rollers for free :-)

Take Care all!