Last thursday i took the car to a local tuner shop to get the AFRs checked and get my first dynos done. it was on a dynapack which i'm not a fan of, but it was better than nothing. I needed to know if the AFR was safe to even drive so i couldnt really be choosey. After 4 pulls i discovered a oil leak, a slipping belt, and an EXTREME lean spike (14.7 the first 2 runs @ 6200). I put down 271 to the hubs and seeing as how the Dynapacks run high i was EXTREMELY dissappointed.

4 days later, ive tightened the belt, fixed the oil leak and decided to take it to another shop, a shop ive taken my car plenty of times to and seeing as how it was save to drive below 6000, i attempted the 40 minute trek.

After a few pulls and some adjustments of the FMU, the car put down 273whp 172lbs trq on a SAE corrected Dynojet. I was only running 4.8 psi as oppose to 6. i'm assuming the extreme humidity had a part to play in the low boost\numbers bc the belt was tight and the clutch was no slipping. On the AFR side of things, the spike was reduced down to 13.6 which will help me sleep better at night. time to invest in a boost gauge and 1 step colder plugs for even more safety. i'm pretty sure on a cooler day, on full boost i can probably hit 280-285whp. regardless considering everything that had happened and the humidity, i was pleased with the results the 2nd time around. anyways heres a video. feel free to chim in.

http://www.facebook.com/#!/video/video.php?v=2197411102140&comments

 

Cool. U figure out why boost is down? What us ur elevation?

 

Congrats...I just got my S1 dyno'd, too (thread's on the same page).

elevation is going to be a big variable, and temperature. I'm at sea level and made 305 at around 92F at very high humidity, but on a lower-reading Mustang dyno, so maybe the equivalent of ~320 on a dynapack. I also only hit 5psi...hot air is less dense.

Have you had your injectors cleaned and flow-tested? RC turns that around FAST, though with overnight shipping, expect to spend $150 or so.

I have the same lean spike...let me guess, between 6000-6500RPM then returning to normal (I only get to about 13.5 though)? SOS told me it's not normal, but many here say it is...I want to fix it!! SOS thinks the cause (and I agree) that the fuel pump is not getting enough voltage and current. I will be running a wire from the battery through a relay to the fuel pump so it gets the current it needs and the full 14.4V instead of the 12V the car feeds it through the teeny wire.

Do you have a wideband, or are they using a tailpipe O2 sensor to read AFR?? I would HIGHLY suggest you get a wideband O2 sensor and gauge mounted full-time. The tailpipe sniffers are not as accurate as a wideband before the cat. If you don't have a wideband on your car, I would say that's why you're running a little low. Having a wideband on mine gave better accuracy and allowed me to get the fuel pressure regulator adjusted well...you may be running rich at the top end...yet the tailpipe O2 sniffer could be reading that as 11.5:1 when you may be falling near 10:1!

Other causes of the lower power reading could include clutch slip...you on the stock clutch?

 

im over in southern VA so im not sure of the elevation but i can assume its pretty close to sea level. the lean spike was right at 6200 and immediately dropped. we adjusted the FMU and brought it done to a more tolerable area and he didnt use tail pipe sniffers. the wideband went in my test pipe. i just recently replaced my stock clutch with another stock clutch and im positive its not the clutch. the few times ive been WOT i havent felt any slipping but when the time comes i will upgrade. according to the guy who worked on it, 285-290 was the average he saw with the SOS stage 1 kits in my area so i'm not too far off. as far as my injectors go i have yet to send them to get cleaned. i plan on picking up a spare set and having them sent to be cleaned. maybe that will help some.

 

Heh, I was about to post my similar results to Jack - hell, I dyno'd on a Dynojet the day after his first post in this thread!

My best was 267 rwhp, ~167 torque. Unfortunately, I didn't have the budget or time to do a baseline dyno, I wish I did though.

I have a similar sort of AF 'spike' around 5800, but to only 13:1. I never worried about it, and the dyno operator pointed out that the car is just beginning boost at that point.

I'm also not seeing 6 psi of boost either, maxing at 4.93 at redline. SOS tells me a pound of boost could be worth 10-20hp. I guess especially at the top end too. Chris at SOS also figures on losing maybe a quarter pound of boost at about 2200' elevation, which is where I'm at, and up to 3/4 to a full pound of boost at 5000'. He advised to check for boost leaks, which is simple enough, and to double check belt tension. The day I went, it was humid for our climate, but not hugely so - apparently it was 19%.

I did have to lean out the FPR nearly four full turns to get the AFRs to follow the curve set out in the install manual. I was getting a light throttle hesitation at about 4-5000rpm before then, but now it's gone. My fuel pressure is right on the money for the curve set out in the manual too, topping out at 74.2 psi.

And I've been trying to figure if gearing has an effect on numbers, forgot to ask SOS about that. My car's an AP1 (with about 153,000km on it), but with AP2 trans and 4.44 rear end. We ran the initial runs in 4th, but later went to 5th. I forgot to do my homework before the dyno as to which gear is the most straight through with that combination of drivetrain components. Oh, and a Fidanza flywheel, but Exedy OE replacement disc and pressure plate. Also have a Tanabe dual exhaust and a straight pipe. The other thing I'm not 100% happy with is the O2 sensor bung on my straight pipe. I wasn't impressed with the shop's work, there was scraggly crap everywhere, and not as much penetration (sounds dirty) of of sensor into the exhaust path. I may rectify that with another bung, but it'll be one ugly straight pipe.

I wasn't hugely happy with the numbers, but without a baseline to compare, it's difficult to gripe. But it seems similar to Jack's dyno, so I'll investigate the belt tension again, and look for boost leaks too. A note on belt tension too - I am not using the original Goodyear Gatorback belt supplied with the kit. I posted a while ago about how the pulley came off and shredded the belt. I'm using a Dayco part with the same specs. SOS told me that they prefer the Goodyear Gatorback for its tension characteristics after having tested other brands, so maybe I'll go back to the Gatorback.

 

how exactly would you check for a boost leak? all my couplings are on tight. also, similar to steven's graph, my power drops just before redline as well. its weird that all of use have different numbers and similar patterns in power and AFR. maybe i just have a weak motor.


as far as gearing goes, i'm running 4.77s but i wouldnt think it would reduce the amount of power made in fourth gear, then again i am no expert so i could be wrong.

i cant get my scanner to work so i had to use a phone pic.



this is the closest thing i have to a baseline. my car tuned on vafc with the same exhaust and a PLM header

 

Chris suggested spraying some soapy water onto the couplers, and then rev the motor. If it's bubbling, then you'll know some intake charge is leaking. I guess it may not be readily apparent on a visual inspection. I mean, large tears or improperly mounted couplers will be quite obvious, but a small leak, maybe not so much. Looks like you're seeing a 70rwhp gain. I was hoping to see a full on 90-100rwhp gain, and similar in torque. Chris had mentioned that the stage 1 kits were dyno'ing anywhere from 250rwhp to 320rwhp, so there is a big gap there. A lot can be down to dyno type and even the dyno operator, plus calibration, not to mention the mods, temperature and elevation variations.

I was thinking of booking a couple hours on the dyno to do an NA pull and then back to back with the charger fitted. Would be a slight pain in the ass though, what with all the parts that need to be moved. Or maybe go the other way, as removing the charger is easier than lining everything up and putting it back together. Might be too much hassle though.

 

They sell a tester for bout 40 bucks if ur worried.

 

I've only got a direct to PDF scanner at the office, but here is the data from my best run. This is in 5th gear, and if I remember right was the fifth (of seven) pulls, all done within about 45 minutes. Maybe some heatsoak issues there too? I'm using just the stock heat exchanger BTW, not the upgraded on.

 

Jack, saabateur, do you have an aftermarket exhaust?

I have the CT, and I'd bet that is contributing to my numbers, as it should be substantially increasing flow. My baseline was 191 bone stock on the same dyno and operator, so my gain is ~115, and I only expected ~90-100.

If we assume my exhaust added 15, that puts me down to 290, only 16 more than you. That could certainly be calibration or gearing differences or plenty of other things. In my experience, the gear selection played a big part for me. I think the dynapacks allow you to put in an overall ratio (5.50 in 4th on an AP1...1.16 4th * 1.16 primary reduction * 4.10 = 5.5). I really don't know much about how gearing is set or affects a dyno reading, but in my experience, 4th produced higher numbers than 3rd. You have 16% shorter gearing than me, and I'd imagine that HAS to affect something. My dyno operator said to select the gear closest to 1.0, but no way am I doing a 5th gear run!

Also, I notice from your chart that you are dipping real close to 10:1 at about 8K. I had the same thing, and did about 1/5 of a turn on the FPR. That took me from 287 to 305. I had thought of loosening a little more to see if my dip was due to AFR, but I decided that what I had was safe, and I didn't need to get greedy.