[Harvey]

Is there physical (Dyno) proof of significant HP increase after chipping a 968? Is Autothority the best route to go? I have them in my '85S 928....and I "guess" that it makes a difference but I just know that, at idle, I smell more unburnt gas fumes. At full throttle I suspect that gas gets used. But I have no proof other than seat of the pants (which sometimes gets wet when I'm on the track with other cars). BTW, at the last Spokane, WA Track Attack, a previously beautiful Guards Red '91GT (928) rolled 3-1/2 times coming out of turn 5. No one hurt and no relation between that incident and the car being chipped. Coming out of turn 5, one of my tires always smokes like heck...I don't have LSD. I just bought the 6-speed 968 (1994). I don't know if it has LSD or not. I'm guessing that the 968 would perform better on the track (traction wise) than the 928. To chip or not to chip...that's the question. And if so, which has the best verification for improved performance.



Harvey

147mph in 4th gear...and one gear to go! (928)

Partial Post: Please Login or Register to read the full post.

[Greimann]

To make a looooong story short, the best chip is the Racer-X chip from Speed-6

Makes 14.5 hp over stock

Partial Post: Please Login or Register to read the full post.

[RS Barn]

Sorry to break the news but I dynoed all the performance chips avaiable and there was only a 2-4 hp gain and a loss of peak torque. The racer X had the most hp but had a loss of peak torque as well. the stock setup is pretty efficient.

I did all the development work on a Mustang dyno which is considered by most tuners to be the most accurate for testing true gains. The shop (Cyntex)that did the development work supports a 997 Grand Am cup car as well as several BMW Grand Am race teams. One of the owners was a partner at Autothority and developed their 968 chips.

RS Barn has developed a performance chip for the 968 that outperforms all others tested with out any torque losses. I will not post any graphs until I have the hard data. This is important as well to see where gains and losses are.

Pete

Partial Post: Please Login or Register to read the full post.

[Eric_K]

I'm not current on the Spokane turn numbers, is turn 5 the hairpin? You will get less wheel spin in the 968 just because you won't have all the V8 torque. A LSD would eliminate the one wheel spin as well. Check the option sticker for 220, that will indicate if you car has a LSD. I would guess the 928 might be capable of better lap times at Spokane because of the looong straight (1.1 miles) - which I've heard is the longest in North America.



There is no reason not to chip it, I just wouldn't expect a night and day difference with any of them. I'll let others debate which one is best. I'm running a chip from Superchip.



Eric

Partial Post: Please Login or Register to read the full post.

[flash]

i enjoyed our phone conversation, and am looking forward to seeing your data



i don't want to be argumentative here, and am only trying to get the most out of the car, just like everybody else - a lot of work went into establishing a test procedure that would produce accurate results - steve dinan wrote a very good 20 page article that explains it - to validate your results, i would have to ask a lot of questions like:



what was the ambient temp

intake temp

humidity

diff temp (very important)

time between runs (very important to be within seconds)

how many runs

time with no chip in the car between swaps (extremely critical)



it took us 2 days to test all the chips properly



multiple tests on multiple dynos all showed results in similar numbers - none of them were as low as yours - i would suggest that some investigation be done to determine exactly why that happened - i can see that your fan is nowhere near big enough to do the job it needs to do, but i think there might have been something else going on there



as for the mustang dyno being considered the most accurate, i guess that depends on the tuner - i know a of guys who think that thing is a toy, and not for real testing - same for the dynojet - i also know guys who swear by both



we all can feel the difference with the chip - it works extremely well - i seriously doubt we could feel a mere 2-3 hp, so i tend to think that it is considerably more, which is supported by the testing from every one of the chip manufacturers and my testing as well - you know tha rule "throw out the low and the high, then average the rest" - skipping any of the above measurements, or rushing through the testing, or not haveing the right fan, and many other things can easily skew the results - differential temps alone can make a 20hp difference



as you say though, it's the comparison that is important, and not the final numbers - i'm anxious to see the new chip

Partial Post: Please Login or Register to read the full post.

[RS Barn]

We did have a nice discussion and both agreed and disagreed on certain items. Gains are gains. All runs with stock and modified chips were within a few hp. All the factors contribute to variances. We didn't have any weird pulls or results. Did your car have modified exhaust and aluminum flywheel on when tested?

Did Greimans car have AFPR on ? These are variables too. You mention other dynos with similar results to yours. What kind and what results.

You will definitely feel the improvements with a modified chip. There is a nice gain down low and more power and rpm up top. The carachter of the car is changed in a positive way.

What I was trying to accomplish with this testing was not to develop a better chip for 968 stock but have that be a starting point for getting significantly larger gains form a combination of products. These were just the results that came with testing.

Partial Post: Please Login or Register to read the full post.

[RS Barn]

And another thing! Just kidding.

In an ideal world we could check out performance gains on an engine dyno. But in our world we are both using rear wheel dynos that read differently. My gut reaction to dyno performance gains vs how it feels is that the engine dyno would show somewhere in between our results. I realistically think 8-10 engine hp could be a real number.

Pete

Partial Post: Please Login or Register to read the full post.

[flash]

we tested on my car and on dave's as well - dave's afpr was dialed back to stock pressure, so his car was the "stock" platform, and mine was modified - results were consistent



the other dynos were ones used by each manufacturer in their own testing, and their results were extremely close to what we got, within a hp or 2, but all at or above 10 - i am sure that they did not use the same kind of dyno we did, as there are only 2 of them in the country - that would mean that our numbers from this dyno, and the numbers from other dynos concurred - this would tend to validate the numbers of all of them



i absolutely want to applaud your efforts - we need more people out there working on stuff for these cars - i am only suggesting that there should be some investigation into why your results were so different from all of the other testing that other people did - there is probably something basic in the test procedure or setup that is skewing the numbers - if it walks like a duck...........



don't think for a second that i'm saying anything about your chip, or that a chip couldn't be developed to beat the Racer X - i'm pretty sure that could be done, even though the guys at brainstorm thought it was maxed out on 91 octane (RON + MON/2) - i'd love to see something better, especially something that worked with my other mods, and i have plans to work on that pretty soon



developing something that worked in conjunction with other components is very exciting - we all eagerly await the results of things that will work on street cars - low end torque and horsepower is what we all want, and far too often all we see is stuff that works on race cars or only at top end



keep up the good work and keep us informed

Partial Post: Please Login or Register to read the full post.

[rustech]

RSBarn, FYI, we all (East Coast and West), are in agreement, that the top chips, Speed6 and Promax(original), not only improved drivability, increased low end torque, but had a significant improvement in top end pull.



All of these opinions were merely formed on the "seat of the pants" feel, and were proven by Flash with the assistance of Dinan and Brainstorm.



Everyone asked would know it was more than a 2-4hp gain and NO loss of torque. The stock chip feels like a slug.

Partial Post: Please Login or Register to read the full post.

[RS Barn]

My tests verified Brainstorms results in general. I'm clearly stating which chip won and that there are noticeable gains in torque at low end and hp upstairs. My only issue is how much. The Mustang dyno tosses the high and lows and shows real gain. Call it adveraging if you wish. What it doesn't do is pick the peak gains. This gives low numbers for gains but there consistent and repeatable. That way anything extra I did to the car had a baseline to the best chip. I did come up with a chip that was slightly better than winner-but not much. They did a very good job.

Partial Post: Please Login or Register to read the full post.

[flash]

i get that - the sampling rate is a variable that i don't have comparison numbers on right now - there is a lot of stuff going on in the software of each system that factors into determining what results you get



in a perfect world, we would have the engine out of the car and eliminate all of that back and forth educated guesswork of real load versus measured load



i've been doing some reading up on the mustang - it does some calculating for road forces that makes the end results potentially more useable for real road power than a dynojet for development of products, though i need to do even more research to determine if it is more accurate than the DTS, which we used, and has been touted as the most accurate system out there - what model of mustang did you use?



onthe subject of fans, the mustang models are all showing a fan that is only 5500cfm to try to recreate real road wind - the fan is one of the most expensive components of the system, and therefore may be why they use that smaller unit instead - their marketing is directed toward affordability, and a bigger fan would add a lot of cost to the package - we found fan placement was critical - moving it a matter of a couple of inches made big changes - in a conversation with steve dinan, he said that even the monstrous fan they use, whihc puts out a lot more air than the one you or i used, is not enough to really create "real world" loads - this brings into question any "correction" that a dyno might do - at that point, it seems that the best thing to do is merely measure what is at the wheels and not try to correct back to the flywheel, and leave all that voodoo math out of the equation



i think we all agree that nobody could feel 2-3 hp though, and that really it has to be close to 10 before you can feel the difference - clearly we can feel the effects of the chips, not just the Racer X, but really all of them - it would therefore seem logical that the improvement is above the threshold of what can be felt - coupled with the fact that the other tests done by the manufacturers all seem to agree with each other, as well as our tests, and all were at different facilities on different dynos, it seems to bear out our results, and that is one of the reasons why i think something must have been wrong in the setup of your test - in running down the list of questions i posted, did you take all those measurements, and maintain exact time steps between runs? - there has to be some explanation for why your results are so different from all the others, yet can stil be felt



very much looking forward to seeing what you have come up with though - i'd love to smooth out the pre-peak line a bit - did you ever get the data on the air/fuel mixtures and find out what the deal is with 4th gear versus 3rd gear?

Partial Post: Please Login or Register to read the full post.

[Harvey]

Eric,



Yes, turn 5 at the Spokane Raceway is the hairpin..and it's angled bad coming out of the turn, I feel. I don't think the straightaway is 1.1 miles long since the entire track is only 2.5 miles long. The straight is a dragstrip...1/4 mile plus less than that to slow down (I think). At least it seems shorter than that but it could be that the speed makes it seem shorter. I went (accidently) in to turn 1 at the end of the long stretch at 118mph and was in a 4-wheel slide. Maybe that was just me nad my approach to the apex but I don't want to do that regularly without more training. Fun track. Great P-cars.



In the 928 I can't top 147 in the straight (in 4th) but there are more powerful cars (or supercharged 928s) that can get close to 170mph or so....but if you can't slow down, you're toast since the runout is really bad. That's where brakes may be more important than the engine! When you add HP and speed...and you don't add better brakes, you're asking for trouble.



Harvey



I'm not current on the Spokane turn numbers, is turn 5 the hairpin? You will get less wheel spin in the 968 just because you won't have all the V8 torque. A LSD would eliminate the one wheel spin as well. Check the option sticker for 220, that will indicate if you car has a LSD. I would guess the 928 might be capable of better lap times at Spokane because of the looong straight (1.1 miles) - which I've heard is the longest in North America. Eric

Partial Post: Please Login or Register to read the full post.

[Eric_K]

Harvey,



The straight may not be 1.1, I was just told that. It is undoubtably long and at least 3/4 of a mile. I haven't been there since 2002 and I remember being short of 140 in the street 968. I do have a lap video I can post. I plan to be there for an ICSCC race in the middle of July - we'll see what the race car can do out there.



Eric

Partial Post: Please Login or Register to read the full post.