weaklink

what happened to the 550hp/460tq figures Pettit advertises?

drc

Thats only when going down hill...:-) Ya, I don't see it getting to those #'s with the cosmo turbo's...but what do I know.

They were doing allot of dyno pulls, I'm wondering if the car was pretty well heat soaked. I drove the car before it went down there and it drove great under boost @ 8lbs(off the spring). The acceleration is a little decieving because it didn't hit me hard like when my single comes on, it was very smooth all over, his car is a really sweet to drive, it even has power steering, AC and a working radio...That's crazy!. Made me wonder what I had done to my car to make it so uncivilized...lol.

I remember nailing the accelerator in 5th around 3K thinking I was in 3rd wondering why it felt a little week then I realized I was in 5th...pretty impressive torque low down. You get another 1000RPM of usuable throttle.

Then evidently the gremilins came out...electrical problems fuel pressure problems..gees. Sounds like they got it all worked out.

I'm anxious to see how it feels now. My car isn't the fastet 7 around but runs real good, 12flat @118mph on street tires with a slipping clutch last time at the track...I have new clutch, lighter flywheel, mazda comp motor mounts installed now...I'M CALLING YOU OUT...:-).

Congrats David, talk to you later

jsplit

David,

My offer still stands to host the videos for you. Just let me know if you're still interested...

Red-Rx7

That is BHP and at 15 psi.

David Hayes

iTrader: (6)

Thanks. Doug (PalmTreeDoc) took some pretty good vids of the car. He's going to put them on a DVD for me and I'll send them on to you for posting. He's in Lake Tahoe now so it will be next week before this happens.

David Hayes

iTrader: (6)

To convert to BP (or crank HP), the measurement used by all car manufacturers, divide RWHP by (1 minus drive train loss). So, for my numbers, I would have 385 RWHP divided by (1 minus 20% or .8). Thus, I would be 385/.8 or 481 BHP. Pettit has advertised for some time 500 HP (don't ask me what happened to the other 50 that is quoted in the article!) so I'm 15 RWHP or 19 BHP off from my goal. Of course my numbers are also at 10 PSI and I'm sure Pettit's are based on a higer PSI level. Don't exactly know if torque uses the same conversion method but if it does, then I'm now at 456 ft. lbs of torque or about what Pettit claims.

As Dean (DRC) knows (common Dean, I'll spank that yellow 12 sec punk *** car of yours!), this has been quite a project. My issues over the last 45 days or so have dealt with the electricals of the car. The Wolf EMS seems to now be working extremely well. The car starts and idles flawlessly and we now have a very smooth AFR curve. As soon as I receive the Dyno file from Pettit, I'll post it. I think you will be impressed with the results, even though I "only" have 385 RWHP at this point.

Unfortunately, it took us many, many hours of work to get to this point. The Wolf unit blew a section of the circuit board and we had no idea this had happened:



Check out the circled section of the board. So, we were dealing with a bad ECU for several weeks, trying to figure out why values and numbers would randomly change in the fuel maps and why our results for tuning would keep changing. Kudos to Cam from Pettit for identifying the issue. It was his idea to pull the unit apart and inspect the circuit board. He's since fixed the board and added a resistor so the problem won't happen again. Wolf Australia claims the issue doesn't affect the performance of the unit, but our results seemed to indicate otherwise.

Thus, the ECU issue was fixed and all was well, right? No! We then ran into a secondary set of issues - voltage to the fuel pump (an upgraded Denso unit). Turns out that voltage for the fuel pump would drop but only after the car was running for some time. So Cam would tune the car, get close to where he would want to be and then the voltage issue would cause fuel pressure to drop and the car to run lean. Cam traced the voltage issue to two faulty relay units and a bad wiring job for the fuel pump performed by Speedcraft in Jacksonville. This took several days to diagnose and fix. The car now has a dedicated relay to directly power the fuel pump (which was replaced again with a new Cosmo unit just for good measure).

So, now we're set! Cam tells me to come down as he'll have the car ready by Thursday. I book a flight down (Southwest, $80 bucks, a good deal) and show up at Pettit Thursday morning. Doug also showed up to video the car on the dyno. Allis well until the fuel pressure starts to go whacko again. Turns out that now the fuel pressure regulator is bad. So, this gets replaced with an adjustable unit that immediately solves the fuel problem. Seems like the car is jinxed, doesn't it? Cross your fingers but it now seems we've identified and resolved (for now) all the issues.

So, as of late last week, we got the car tuned up to 10 PSI and the results I described earlier to you. Because of the torque band, the car pulls very smoothly across the entire RPM band and is an extremely fun ride. My goal for this week is to do a lot of data logging to identify any remaining issues, especially at higher boost levels. At Pettit, we did a run or two at 12 PSI and didn't see RWHP and torque increase much. Could be something with the tuning, or maybe we have hit the limits of the turbos, or something else. I'm going to ask Dean when he gets back next week to review the data logging results to see where we're at and if I'll continue adjusting for a higher RWHP level.

Hope this explains the wild ride I've had the last month. I'm now headed out to wash the car and work on a few small projects on the car. Will post some pics later!

jimlab

Do you have an automatic transmission? Use 0.85 for a manual.

David Hayes

iTrader: (6)

Nope, I have a manual. Jim, my car in stock form dynoed in at 210 RWHP before any modifications. Therefore, my correction factor would be 0.82 (210/255), or my drivetrain loss would be 18%. My understanding is that this is pretty normal.

I used 20% to make it easy, but using the 18%, the BHP would be 470 and the torque would be 445.

David Hayes

iTrader: (6)

I can only say this about Dean's car because I know he can't respond for the next week or so so this gives me free reign to talk without any response!

FYI - his car is very nice as I am sure Jim's will be. Remeber, he's doing all the work himself and his car will be a one of a kind supercar.

jimlab

You're assuming that your engine made 255 horsepower stock, which is not necessarily the case. The rated horsepower simply means that the majority of engines produced make that much or more. Some make less, of course. In other words, production variances and other factors ensure that not every engine makes precisely the rated power.

Furthermore, it's generally accepted that average RWHP for a "healthy" stock FD is 217-220 SAE corrected, so I'd say your stock engine was a little weak or you had a minor issue keeping it from making full power.

No, not really. Most manual transmission cars are around 15%, and some are even lower (more efficient). For example, one supercharged LT1 owner on CZ28.com measured a ~12.5% loss through the T56 and GM 12-bolt vs. the flywheel horsepower he attained on an engine dyno.

The only way you'll truly know what your drivetrain losses are is to do back-to-back engine and chassis dyno runs. For manual transmissions, however, 15% is the widely accepted standard percentage. 18% would be an automatic with a good low-loss converter, and 20% would be worst case scenario for an auto with a sloppy stock converter.

And using 15%, you'd have 453 and 429. Considering that Pettit pushed 15 psi to make 550 flywheel horsepower, 453 isn't out of line for only 10 psi.

jimlab

Predict this...



Untuned (note the very rich A/F ratios) and with ignition break-up through peak power (6,900-7,200 rpm).

550 RWHP is not a prediction, it's pretty much inevitable.

SpoolinRX

iTrader: (6)

Yeah inevitable

cloud9

iTrader: (4)

Serviced...

David Hayes

iTrader: (6)

I have no information one way or another to agree or disagree with what you are saying. I'm sure you've done your research. However, we're speaking about my individual car. What we do know is what it put down in stock RWHP. The only other thing we do know is the average engine HP published by Mazda. Sure, this is an average but it's the best number we have.

The car could have had an issue, you know how complicated everything is on the FD. I doubt this though as I have owned the car since it was new and had a pretty good rotary master mechanic working on the car. Before the car was dynoed I had it serviced and checked out - didn't want to blow anything up!

You are correct about the only way to truly know is to do back to back engine and chasis runs. Unfortunately this will never happen for me. No way am I going back and having the engine taken out! As you have engine HP numbers, it is going to be cool to see them matched up to the chasis numbers - that is if you are going to have the engine tuned and retested before installation. The engine is already in though isn't it?

Anyway, my current plan is to data log the heck out of the car this week to see how the engine is operating.

jimlab

Well, that and what all the healthy stock FDs have averaged over the years: 117-220 RWHP.

Nope, but it won't be final tuned before going into the car. However, the cam will be changed out and peak numbers should be around or a little above what the untuned numbers for the first cam were (640-650 horsepower). The first cam was probably good for about 675-680 after tuning according to B&B Performance.

Great. We're all interested in seeing the results.

John Magnuson

Not only do stock power levels differ but a lot of dyno machines themselves will differ in their readings from machine to machine. At Dyno days I've seen a totally stock FD dyno at exactly 255hp at the wheels. What is comes down to is that RWHP is a poor way to measure an engines power and should only be treated as a very rough approximation of engine output.

SPOautos

I'm sorry but I just feel Cam charges too much for a 20b swap considering it comes with the stock turbos, Wolf ecu, and basically a stock fuel system. I think it would be worth the money if it came with a better ecu like the Haltech E11, Tec 3, or Autoronic SM4, nice single like a T72 or GT42, and a fuel system capable of 650rwhp. Something like that all setup and tuned would be worth the $35K+

just my .02

Stephen

jimlab

Not SAE corrected, you haven't.

No, what it comes down to is that operator error and deliberate tampering with the results are always possibilities.

SAE corrected figures should be relatively comparable from machine to machine of the same type (Dynojet vs. Dynojet, Mustang vs. Mustang, etc.), regardless of location. The conversion factor used is intended to factor in DA (density/altitude, or in other words, elevation, air pressure, and temperature) to equalize the results with other facilities.

When you see a chart that says "Max Power" instead of "SAE Horsepower" on it, that's your first indication that no correction factor is being used. Typically, those results are higher than SAE corrected numbers, sometimes significantly higher. The correction factor can also be changed by the operator to bias the results.

David Hayes

iTrader: (6)

Everyone is entitled to his or her opinion. The Pettit conversion is way more than what you've described. Check out my earlier posts as to what has changed on the car. The "stock" turbos are balanced and ceramic coated twins. I could have gone single as several of the other Banzai guys have done but I choose the route of lesser HP for a more linear and lower starting torque curve. I can always swap this out for a single if I like. The fuel system has been reworked as well and can easily support the HP I'm trying to make. The problems I had were related to the voltage relays on the car, not the fuel system. Finally, Cam has always used the Links ECU in the past as he has these tuned and "out of the box" ready. Unfortunately, Links no longer supports the 20B so he had to go to something else. It's been a difficult process with getting the Wolf installed and working, but now that I'm there the unit works very, very well. It compares favorably and has more features (like OMP support) than the units you described. Cam almost removed the Wolf for the Haltech E11 (or a Microtech) but we were able to overcome the issues that we were experiencing to our satisfaction. And the support from Wolf can't be beaten. I also know that most everyone has some form of issue with ECUs when first installing and we probably would have experienced something or another with the units you described.

So, I guesss to each his own. I'm very satisfied with the fabrication work and the job done by Pettit. After seeing what happens to make the conversion, it is a very brave person (and more talented than I) who attempts this himself (Herblenny)!

weaklink

Well it certainly did a lot to lessen my 20B fever. There are other routes to 385+rwhp. Wolf has great support? Are these the same people that told you the blown circuit was fine? I think the great support you got was from Cam.

SPOautos

I know Cam does good work and when he finishes everything it should be 1st class and bug free. Also, I didnt suggest those parts because of your difficulties. I realize what goes into a 20B swap, what the cost is, and how much work it is. I suggested those ecu's because they are better quality units. I wouldnt run a Wolf on a 300hp 13B car, much less a 20b car that I'm paying someone 35K to modify.

Dont take my comments wrong, I like Cam and think he does a good job. I just think that for the price he charges he should build it up a little more, thats all.

Stephen

HDP

iTrader: (2)

So you were somewhat of a guinea pig for the Wolf unit? What happens when the Summer months roll in and you want/need to use your A/C?

David Hayes

iTrader: (6)

What other routes are there to 385 RWHP AT 10 PSI? And how about 365 ft. lbs. of torque available at 3,200 RPM and throughout the entire RPM band? Don't think you'll get this with a 2 rotor. Like on the 2 rotor, 10 PSI is nothing and is very, very conservative.

I didn't say I was going to stop at 10 PSI. The twin turbos on the car are good for up to 15 PSI but my point was now that I'd like to take a breather and enjoy the car at the current "low" level of 385 RWHP. I'm sure that I'll get anxious soon to turn up the boost and see what happens.

My comments about Wolf related to Chris Greene. He called everyday (including today) to ensure that things were going well. And yes, Cam is great support too.

David Hayes

iTrader: (6)

Yep, I was a guinea pig. Fortunately, we've already had some pretty hot days down in West Palm so I'm not too worried about the tuning at this level. What I was worried about was when it got cooler but this has been tuned for also as we've had a recent spell of cold weather, at least for Florida.

t-von

iTrader: (8)

Yea but what about when it does get warmer. Will you still be able to get the A/C working?