We had poor conditions, it was cold and raining. This was on a Mustang dyno, too, and the guy running the dyno used a correction factor of 14 for everyone. Later we looked at a list of vehicles he had that told the correction factor and weight for a ton of cars, including mine. The weight isn't as big of a deal as the correction factor, which was supposed to be 12.5 instead of 14. Basically, at 50mph (assuming still air), I'm using 12.5hp to overcome all drag (just to cruise at the same speed). This drag (wind resistance, rolling resistance, drive train losses and such) will increase significantly as speed increases. At a difference of 1.5hp at 50mph, that could probably equate to another 5hp I'm actually putting down. Additionally, since we had poor weather and I forgot to bring a bag of ice for my IC, I probably heat soaked like a cheetah, a few seconds of glory and it's spent. This was my second run, the first was not only at less boost, but we didn't get the data correctly because I didn't realize I had to hit a certain RPM that he set for his window. Regardless, Syonyk reported that turning the boost up a couple psi gained me about 20hp (he was watching the live data).

Up top, obviously past 5750RPM, my boost dropped off dramatically. I have a ported wastegate, but unless my mbc vent hole is clogged I wouldn't think it would drop as far as it did. I think I dropped down to about 5psi toward the end. Again, my exhaust is open (no cats, only two mufflers). It may have something to do with a crappy turbo-mani gasket or crappy BOV as well... I'm open to suggestions/ideas/comments/questions.

Relevant mod list: untuned 13Bt in my '87 TII, Rtek 1.7 ECU with 720cc secondaries, 10psi max boost using a cheap manual boost controller and cheap BOV (that may or may not leak some...), open 2.5" dp to a y-pipe splitting to two 2" pipes with a muffler on each, no emissions, manual steering, A/C still installed.

Pulled in 4th gear.

 

Ok, questions I have.

First of all, up around 9-10psi I would occasionally feel a slight hesitation. Now, I know the Rtek retards timing about 1* for every psi over 9 I think is what it does. I'm hoping that's what it is, because I don't think my A/F ratios look bad and my A/F gauge was pegged rich the whole time.

Secondly, I'm wondering if I can use my Rtek to safely get a little more power out of it. I would be so pleased if I could make the same power under a little less boost, or more power out of what I'm running. This is why I had them print my A/F graph. I'm also interested in tuning for fuel economy, but I wouldn't think these results could help me a whole lot in that respect.

 

As far as the hesitation goes, it could just be plugs or some other ignition component if you're sure the grounds are ok. This is the Rtek with the stumble elimination fix? Although this hesitation you describe could be unrelated to injector staging.

Your AFR's are good enough. You could get a couple more HP here or there playing around with an SAFC, but there's only so much you can do without turning up the boost further and increasing airflow. Set the MBC to 12-13psi and I'd expect 230+ on a dynojet with more torque. You are probably at about 210-220ish now which is about right, or certainly within the acceptable range for your setup. I've seen people crank up the boost higher on the stock topmount, but it does heatsoak. I've also seen people do over 300+ whp on the stock intercooler (hybrid turbo), you just have to be careful. And don't be surprised by the boost dropping that low. When I had my stock turbo, I ran 13psi (with a FMIC) but it always dropped to about 6 by redline. When you get a bigger turbo (I have a T04S 60-1 now) sometimes you miss the almost LS1-like powerband of the stocker with the boost cranked up.

As for tuning for gas mileage, the best way to get more gas mileage on a stock ECU is to stay out of boost. I have a standalone (Power FC) and my AFR's on the highway are in the low 15's, but I still get 12mpg because I'm always beating the crap out of the car (what's the point if I don't?). Your car has an O2 sensor that keeps the AFR's oscillating between 14 and 15:1. I've heard of people disconnecting the O2 sensor and playing around with an SAFC but I'm not sure how much success they had. Best bet is to just drive the car easier and do a full tuneup.

 

haha, I should have put my new plugs in before running, they're sitting in my garage. They could even be damaged or fouled after the whole timing fiasco the first 25 miles.

If it's pretty normal that the boost drops off that much with the stock turbo then I think I'll open up the MBC vent a tiny bit more. Hopefully it will allow me to sustain the higher boost yet maintain control of the peak.

My grounds should be fine, but it has a couple electrical quirks all around and it's possible cleaning them didn't fix them. Yes, my Rtek chip has the stumble fix, but the RPM it affects is much lower than where I was experiencing it.

I also had LED's hooked up to the ECU to read error codes. When I hit about 7600RPM, or about 130mph, both lit up for a few seconds without flashing until I let off the gas. I figured since my run was within moments of finishing I kept going to completion. They didn't light up during or after the test except for those brief seconds, and I assume it was nothing to be worried about, but I thought I would ask if anyone even knows why that would happen.

The dyno guy said I might make more power if I richened it up a little on boost. At least I know that adding fuel shouldn't be dangerous, I'm just wondering if it would actually benefit me or if it would just run too rich.

 

The power looks about right...
It's making a little over 200hp (maybe up to 210) on a DynoJet, which is about right for your mods.

What's weird about your graph is that there's a "tail" at the end...
So it looks like you still need to tune your top end, cause it's dropping power too rapidly.


-Ted

 

^^ you can try and play around with the SAFC a little, but there's only so much precision it has... you may find it mostly just hurting gas mileage in normal acceleration. Just see if what happens. If you had an Rtek 2.1 you could do it more precisely.

^ is the "tail" you are seeing on that second graph, the line marked "accel mph/sec" ? that's not the power graph per se, just looks like a derivative of the mph curve on the dyno or something. In the first graph the power falls off a lot less compared to that other line in second graph, or at least to me it does.