dyno results on the super nat 475.....

[kaijumax]

FWIW, I believe Callaway dyno's their packages on an engine dyno, not in the car. I'm not sure anyone really knows what flywheel numbers should work out to what at the wheels. Perhaps 475hp = 375 on a dynojet. Or perhaps his car isn't running 100%. Or perhaps the 475 was generous. Who knows.

It would be nice to have some body of numbers from these cars. Though I can't recall seeing any dyno nor 1/4 mile numbers for any Callaway ZR-1's, except those published by magazines. It would be especially interesting to know what these cars throw down on the rear-wheel dyno because they have engine dyno sheets.

The links Chris put up, as well as ones that describe the whole package, are great reading. Callaway did touch the bottom end, though the cars are still 350ci motors.

This basically describes the package. The 475 package was this but without the header/cats and supernatural exhaust. I believe everything else was included (engine work, flywheel):

http://callawayownersgroup.com/Images/supernatural/s2.jpg

I'd imagine they used stock injectors, because they flow enough to make way more than 490hp. Though I have never owned one and don't know that for sure. But on my car which makes about the same whp, the injector duty cycle at WOT at 7k rpm is only like 55%. They have a lot of room.

Thats not completely correct.
All the Callaway 475's had a high flow exhaust as part of the 475 engine package. Note: the double D exhaust tips. It was the center outlet that was the option over the dual exhaust standard upgrade. I also have the Dyno sheet that came with my car, which were dyno'ed out of the car after the enginges were rebuilt from Callaway. That it is why it is so important to get all of the original paper work when buying a used one . IMO

 

[Hib Halverson]

THE BOTTOM END HAS BEEN CHANGED IN THE SN475 AND SN490 PACKAGES.

When you say the bottom end "has been changed" can you be a little more specific?

 

[Hib Halverson]

we get that junk winter gas . starting in april it changes . so says a friend that owns the local chevron .the dyno run was done in bakersfield / well actually buttonwillow raceway @ just 7s racing. on the top of the sheet it does say winpepbut says uncorrected . will call tomarrow and see if i can get corrected results . are the denso o2 sensor avail at most of the auto part stores . i,ll try to take some picks of the porting when i pull the plenum. whats a good digital camera to buy ? thanx again for the help

Unless you are buying fuel from "off-brand" stations "winter gas" is not "junk" at least not from the standpoint of octane. Now one thing that is an issue is if the gas sold up there is lower octane which is common in counties with most of their area above 3000 ft. If your premium or super unleaded is 88 or 89 octane, you won't have a problem as long as you burn the fuel up in your area. But, when you go down to Bakersfield, then you'll have a problem on the dyno. You need to either fill the near empty tank in Bakersfield or mix a higher percentage of race gas before you run.

You can find some information about gasoline at:
http://www.idavette.net/hib/fuel/index.htm

As for the dyno data, if the chassis dyno vendor kept the file on your car, it will be easy for them to convert it to SAE net. Uncorrected data is useless other than for back to back runs, on the same dyno, under the same conditions for the purposes of testing mods.

The Denso O2S is a better design. Denso O2Ses are now used on some late model GM applications. They can be ordered from any auto parts store which retails Denso products. All my cars with O2Ses have been upgraded to the Denso sensor...that includes my ZR-1.

Lastly, there was some mention, above, of rear wheel power vs flywheel power. Generally, the driveline loss in the C4 manual powertrain was about 18%. If you're working with SAE Net rear wheel power then a reasonably accurate conversion can be derived for SAE net power at the flywheel by dividing the SAE rear wheel figure by .82. Using my 95 as an example, we saw a peak of 413 rwhp SAE corrected so, at the flywheel, the engine makes about 500 hp.

Now the driveline loss figure makes some assumptions
1) trans, axle and other driveline parts in good condition.
2) OE lubricants in the trans and axle
3) OE tires at recommended pressure.
4) OE powertrain mounts in good condition
5) OE brakes and brake pads
6) OE wheel bearings
7) OE front and rear alignments

Obviously, there can be some variance, but 16-20 % is a good range.

 

[kaijumax]

When you say the bottom end "has been changed" can you be a little more specific?

I think I should clear up some mis-information.
The only rework to the bottom end of the Lt-5's done by Callaway was to have a option to change out the factory rods for Oliver rods. These were only available when the 490 packages became available, I believe around 1995. The rods or any rework to the bottom end is not listed in the earlier 1993 brochure. All rework was in the matching of the heads and intake, along with calibrating the software to the new porting. The cams and spring adjustments were also "blueprinted" when re-assembled.:cool

 

[bradslt5]

wow , i am learningalot of new stuff .Hib, thanx for the dyno info . who in so cal has a good dyno to make an appt with? the rc injectors should be here monday so hope fully be the end of next week i will have new sae figures . my car was done in july of 93 so the bottem end i guess is stk /factory . it has corsa exhaust and i dont know how it compares to what callaway puts on? any ideas / thank you very much for all the feed back guys

 

[*89x2*]

... it has corsa exhaust and i dont know how it compares to what callaway puts on? any ideas / thank you very much for all the feed back guys

Corsa exhaust may have a sound that some like, but it is not nearly as high-flow as the Callaway exhaust I have seen when compared to various brands (Corsa included).

Here is a pic. of the correct Callaway exhaust:

 

[Hib Halverson]

I think I should clear up some mis-information.
The only rework to the bottom end of the Lt-5's done by Callaway was to have a option to change out the factory rods for Oliver rods. These were only available when the 490 packages became available, I believe around 1995. The rods or any rework to the bottom end is not listed in the earlier 1993 brochure. All rework was in the matching of the heads and intake, along with calibrating the software to the new porting. The cams and spring adjustments were also "blueprinted" when re-assembled.:cool

As I said, earlier, the SN475s were treated to what's known as a "top-end" job along with some other enhancements and an an ECM cal. appropriate to the mods. And, with respect to the short block, it seems the "490" was basically the same, unless the owner specified the Oliver connecting rods.

 

[Hib Halverson]

Corsa exhaust may have a sound that some like, but it is not nearly as high-flow as the Callaway exhaust I have seen when compared to various brands (Corsa included).

Here is a pic. of the correct Callaway exhaust:

Please, supply data supporting your belief that the Corsa exhaust is "not nearly as high-flow" as the Callaway system.

 

[*89x2*]

Please, supply data supporting your belief that the Corsa exhaust is "not nearly as high-flow" as the Callaway system.

Hib, I am not making a direct reference between the C4 system pictured and a particular corsa design. I have seen test data from C5 and C6 exhausts from Callaway comparing it to other brands flow rates and the popular corsa was included in those. :cool

I am sure if there was something avail. that would have worked, it would have been FAR cheaper to resell that into their package, than to go and design and fabricate/manufacture their own

There used to be a bar graph online somewhere where Callaway compared their exhaust to a "popular one." Care to guess who the "popular one" was

 

[bradslt5]

if i wanted to recreate the original exhaust . where would i find the info as to what to get . i did an almost direct copy of hibs in the article for my black car the only changewas using the magna flow x pipein a muffler which i love . but the boss (wife wants ) me to try to make the original exhaust for this car.

 

[Aurora40]

if i wanted to recreate the original exhaust . where would i find the info as to what to get . i did an almost direct copy of hibs in the article for my black car the only changewas using the magna flow x pipein a muffler which i love . but the boss (wife wants ) me to try to make the original exhaust for this car.

I'd asked Callaway about this a few years back. I'm going from memory though, as I can't seem to find the email. They'd still sell a SN exhaust, though I believe it was in the area of $4,500 and you'd need to take your car there. I guess they don't still have the jigs or whatever they used to fab up the system, so they'd need to fit it to the car.

I also believe they said it was straight-through. There's no baffling or chambers?

As to a general description, the brochure Chris pointed describes it. 2.75" pipes, they come together into a single 3.5" "mixing chamber", then out to the mufflers. If you wanted to make one yourself, though, I doubt anyone outside of Callaway knows what the insides of the chamber or mufflers look like. I can't imagine anyone cutting one open out of curiosity. My impression is they made the mufflers/mixing chamber themselves, that it isn't like pieced together from common parts.

I also recall asking Phil DeJohn of his impression of his. He's got a 415 in front of the exhaust. He mentioned the resonance was low and that he loved the system. It was a bit too rich for my blood though, but I'd love to hear a Z with one on it.

 

[kaijumax]

if i wanted to recreate the original exhaust . where would i find the info as to what to get . i did an almost direct copy of hibs in the article for my black car the only changewas using the magna flow x pipein a muffler which i love . but the boss (wife wants ) me to try to make the original exhaust for this car.

Brad,
The mufflers on my car are embossed with the name "Super Turbo". There is no other information that I can make out that would identify a specific manufacturer. The only company that comes to mind that used that name to describe there mufflers was "Walker". The real problem is trying to find someone that makes mufflers in the 2.75 diameter. Most are either 2.5 or 3".
Hope that helps,
Jim

 

[Hib Halverson]

Hib, I am not making a direct reference between the C4 system pictured and a particular corsa design. I have seen test data from C5 and C6 exhausts from Callaway comparing it to other brands flow rates and the popular corsa was included in those. :cool

(snip)

With all due respect, 89x2, IMO, you are being evasive.

You said earlier

Corsa exhaust may have a sound that some like, but it is not nearly as high-flow as the Callaway exhaust I have seen when compared to various brands (Corsa included).

Now....for one aftermarket exhaust to be "not nearly as high-flow" as the Callaway, would require it to be significantly more inferior.

I have a hard time believing that there would be that much of a difference and that belief is based on 25 years of technical writing about Corvettes, litterally 100s of chassis dyno tests and evaluating a number of exhaust systems.

So....if Callaway's aftermarket exhaust systems are not just better performers than others but are *significanty* better performers (which they'd have to be for the others to be "not nearly as high-flow") I need to become enlightened about the aftermarket exhausts Callaway makes.

Please post the test data you've seen which supports the statement you made about Corsa and Callaway exhaust systems.

If you can't supply this test data, then should I assume that what you meant to say was that you believe other exhausts are not as high-flow as a Callaway system, but you have no data whatsoever to prove it?

 

[bradslt5]

thanx guys for the help. i think 4500 for an exhaust is a little rich for my blood but i think if i had a picture i might be able to find a way to recreate it . i have some really talented friends that love a good challenge .they also love my wifes cooking and since its for her car........its a done deal. does anyone have a pic. or 2 we could use to recreate it . i'll have them give me a blow by blow and perts list so those who want to do the same can. i love the one they did for my blk zr1 it made 25 more hp than the flowmaster . it has a ultra flow x pipe muffler into the same mufflers hib used with the 23/4 in exhaust they even recreated the dual outlets of the stk zr1 tipps . they fabbed the ovalcases to give it the appearence of the stk stuff.. thanx again for the kind help. this is a fun group of guys

 

[*89x2*]

With all due respect, 89x2, IMO, you are being evasive.

Now....for one aftermarket exhaust to be "not nearly as high-flow" as the Callaway, would require it to be significantly more inferior.

I have a hard time believing that there would be that much of a difference and that belief is based on 25 years of technical writing about Corvettes, litterally 100s of chassis dyno tests and evaluating a number of exhaust systems.

So....if Callaway's aftermarket exhaust systems are not just better performers than others but are *significanty* better performers (which they'd have to be for the others to be "not nearly as high-flow") I need to become enlightened about the aftermarket exhausts Callaway makes.

Please post the test data you've seen which supports the statement you made about Corsa and Callaway exhaust systems.

If you can't supply this test data, then should I assume that what you meant to say was that you believe other exhausts are not as high-flow as a Callaway system, but you have no data whatsoever to prove it?

Hib, the data was shared with me on the c5 AND c6 Callaway exhausts and myself and others have had conversations on the C4 exhausts witht he engineers at Callaway Cars. I am sure you understand why they do not put their internal research docs online, but if I find the one chart that was released, I will post that.

In the meantime, my word and integrity will have to suffice. Thanks

 

[Aurora40]

Brad,
The mufflers on my car are embossed with the name "Super Turbo". There is no other information that I can make out that would identify a specific manufacturer. The only company that comes to mind that used that name to describe there mufflers was "Walker". The real problem is trying to find someone that makes mufflers in the 2.75 diameter. Most are either 2.5 or 3".
Hope that helps,
Jim

Wow, that's very interesting. Dynomax actually does make a 2.75" Super Turbo muffler in a configuration that is appropriate for the 'vette. It's a side-inlet, center-outlet muffler in the same case dimension as their "direct-fit" Corvette mufflers. I did not think they made the Super Turbo in stainless though. Anyway, that's interesting to know. I wonder if it is a Walker/Dynomax muffler?

i think 4500 for an exhaust is a little rich for my blood but i think if i had a picture i might be able to find a way to recreate it

You might give them a call to confirm, instead of relying on my memory.

 

[kaijumax]

Wow, that's very interesting. Dynomax actually does make a 2.75" Super Turbo muffler in a configuration that is appropriate for the 'vette. It's a side-inlet, center-outlet muffler in the same case dimension as their "direct-fit" Corvette mufflers. I did not think they made the Super Turbo in stainless though. Anyway, that's interesting to know. I wonder if it is a Walker/Dynomax muffler?


You might give them a call to confirm, instead of relying on my memory.

I don't believe my mufflers are stainless as they are showing signs signs of age, corrosions around the seams etc...
The Walkers are embossed with the Dynomax logo also. I think it will be quite difficult to put the exhaust back 100% original, but it looks like a 2.75 diameter system could be built with a little work.

 

[bradslt5]

ll to ake sure , but my buddies are looking forward to doing this for deb . they just love her cooking. she can get them to do anything. they are going to find the double d tips and build a copy of my exhaust for her car .. there is a private track rental day that a friend of mine is organizing @ famooso. there will be only 100 cars so we will test the corsa against ours which is 3 inch to the ultra flow x pipe muffler then 23/4 to flowmaster 530602 mufflers to the double d tips . i tested this system at a friends dyno on my blk car against the flowmaster cat back system and i believe if memory serves me we made24more hp. what I ilke is its really pretty quiet . i am older now and like the stealthyfeel of this exhaust . we are going to add headers as inyo county only has us smog when we buy or sell a car . another good reason to live up here

 

[kaijumax]

Were all looking forward to see pics of the car. Good luck.

 

[bradslt5]

soon a i can break free and get a camera . i dont know what one to get .i usually mess this stuff up .debs better at getting the right one . what a good easy one that will connect to a computor ? maybe i can get one on tues . your suggestions are very much needed so i dont fubar this otfl