Driving on the dyno.

[SurfnSun]

Im not sure how many of your have driven your car on the dyno, but it is a weird feeling. I really didn't like it that much.

But I'll tell you one thing for sure....standing outside of my car and hearing it wail on the dyno was awesome. Even with stock mufflers and no cats, it made some sweet noise.

We did get the A/F to as close as high as 12.x:1 so that with the 114 octane made it safe. I can tell you one thing for sure, the tuning adjustments on the microfueler dont seem to do a whole lot.

 

[EricVonHa]

Every time I've ever been doing the dyno thing I'm paranoid. It is realllly weird to have your car do over 100mph while sitting still. I check the straps every couple runs and always let it idle for a little while after every run. The people in the shop don't like the sweet smelling emissions but they get over it quickly!

 

[SurfnSun]

yea when they were backing my car on the dyno a couple of the guys were asking if I run highflo cats b/c of hte exhaust smell. I said no...thats 114 leaded they were like...cooool.

 

[90Callaway]

I've "driven" my car on all the dyno pulls I've done. Truthfully, I wouldn't be comfortable having someone else do it. Now that I think about it I never looked at the speed. I was too busy trying to keep an eye on the tach and the boost gauge.

It does sound absolutely awesome running it up to redline in fourth gear in the confines of a small garage.

 

[EricVonHa]

I've "driven" my car on all the dyno pulls I've done.

Me too. It's not cool when the dyno junkie shop employee isn't familiar with the car. Heck, with these TT's you don't even need to rev it to the redline. But, if left in the hands of someone that doesn't know the car they will undoubtedly run the motor till the tach is almost pegged.

 

[Peer81]

Well, i've driven my car on 2 differend dyno's.
The first one i did myself (it was on my school) (all wheels where on rolls) and just for fun, you shoot have seen those first years looking and hear a v8 pull (a v8 is a exception on the roads here!). The only problem was that one off the back straps came lose and that isn't funny when you have a massive wall a couple of meters in front of you. The car went a little sideway's but it ended oke.

The second time was on a single wheel dyno (front wheels on the floor) and the employee did the pulls. Well they also dyno proff. bikes and car's. The only problem was the guy didn't notes that i had the car on the handbrake (big red light between the meters but he didn't notes it). After a inspection of the car because it made a very weird noise the saw the brake. And indeed it's very weird standing beside your own car going very fast..

Greetings Peter.

 

[Ken]

... in the hands of someone that doesn't know the car they will undoubtedly run the motor till the tach is almost pegged.

By rights, they should ask you what your redline is, or rather, at what point in the RPM band you would like to have the run stopped. It's a standard question as far as I know.

 

[90Callaway]

Heck, with these TT's you don't even need to rev it to the redline.

I do all my pulls to 5400-5500rpms but my car is still making power at that level.

 

[EricVonHa]

By rights, they should ask you what your redline is, or rather, at what point in the RPM band you would like to have the run stopped. It's a standard question as far as I know.

Ken, I agree entirely. At the local shop a fair amount of customers are the "Curious" type in that they really don't have any mechanical or technical abilities. They bring their cars in just to see "what will it do?" When asked if they had any idea about to what extent the car should be run-- their reply just may be "Is it related to tire pressure?" :L

 

[jcummings250]

yea when they were backing my car on the dyno a couple of the guys were asking if I run highflo cats b/c of hte exhaust smell. I said no...thats 114 leaded they were like...cooool.

Definatly continuing to admit my "novice" experience level here, but so far you guys have been great about learnin' me somethin'... so, to run "114 leaded" you had to have made some changes from what Callaway did, correct? I've been reading most of your posts, and I know you're always doing something with your car, but specifically to make it run on that particular fuel, I would assume some major mods.

 

[90Callaway]

Most high octane race gas such as 114 is leaded. You DON'T want to use it if you have the catalytic converter on the car. You also don't need it unless you are running a high boost turbo application.

The highest octane unleaded that I've seen is 100.

 

[Peer81]

Little offtopic but oke. Over here (holland and surrounding country's) you can get 98 unleaded at every gasstation, normal is 95... (and the price is way to much )

Greets Peter.

 

[jcummings250]

Most high octane race gas such as 114 is leaded. You DON'T want to use it if you have the catalytic converter on the car. You also don't need it unless you are running a high boost turbo application.

The highest octane unleaded that I've seen is 100.

So, its the cat that prohibits the use of leaded fuel? In other words (not that I am going to do it) but if you remove the cat from any engine, you can now run leaded fuel?

I usually use Sunoco 98, but that's the highest I've seen around here.

 

[*89x2*]

In other words (not that I am going to do it) but if you remove the cat from any engine, you can now run leaded fuel?

I usually use Sunoco 98, but that's the highest I've seen around here.

Sunoco 98 is plenty for a Supernatural - The SNAT was designed for premium unleaded (The Twin Turbo cars have more at stake w/ high octane fuels )

Running leaded gas will eat up your o2 sensor over time - that is / was fairly common with the Buick GN / TTA guys...

 

[SurfnSun]

Higher octane fuel does not make more power on average, it makes less. The higher the octane level the slower the gas burns. Thats why you get pinging with 87 octane, its so combustible that it burns at both ends of the cylinder (BAD). High octane leaded fuel works well with Nitrous or Forced Induction due to the amount of air being put in the cylinder, it burns slower so that way you don't have combustion occuring before the given cylinder is ready to fire. I run high octane gas as a safety net here in FL. The temp is really hot and turbos don't like the heat too much, but my car has poor driveability around town with the stout mix of good gas. It stumbles at stoplights etc, b/c at that point the gas is burning too slow for the motors low compression ratio.

Hope this helps.

 

[90Callaway]

Running leaded gas will eat up your o2 sensor over time - that is / was fairly common with the Buick GN / TTA guys...

Good point... forgot to point that out.

My car runs best and seems to make the most power on Sunoco 94 Unleaded. Using leaded race gas in any quantity beyond 2-3 gallons per tank just seems to reduce power. I get almost no knock counts using a scan tool with straight Sunoco 94.

 

[jcummings250]

Very interesting points. I had known about the lower octane causing premature combustion, but I never realized that you could also fault on the "too high" side. Makes sense though.

How can I tell whether combustion is occuring too early or not? Is there an octane rating recommendation for the SNAT? The spec sheet from Callway for my car said the combustion ration was 10.5:1.

 

[*89x2*]

Is there an octane rating recommendation for the SNAT? The spec sheet from Callway for my car said the combustion ration was 10.5:1.

Hope this helps
********************************************

Callaway SNAT 400
Iron Block alumn. head
OHV 2 v per cyl.
383 cu in.
bore x stroke 4.030 x 3.750
comp. rario 10.5:1
Power: 404 hp @ 5750 rpm
Torque 412 lb ft. @ 4500 rpm
Fuel Delivery - Port Inj.
Required Fuel: Super Premium Unl.
Oil Sump Capacity: 5.5 qts

ss 1/4 mi 12.69@114

EPA mpg
City 15mpg
Hwy 23 mpg

C.A.R.B.
E.O. No. D-319
50 state compliant

 

[jcummings250]

Great info! Where did you find that? I'm always looking to expand my sources for "official" info from Callaway. Or unofficial for that matter!

Thanks again.