Author Topic: av gas yes or no  (Read 13257 times)

hotrod68

  • Hero Member
  • *****
  • Posts: 520
  • almost finished
    • View Profile
Re: av gas yes or no
« Reply #15 on: June 24, 2007, 04:34:56 AM »
Hey, Gary--that was just my humble opinion. Meant no offense. 302 to 400, I've found that a small-block needs at least 10-12 degrees initial to run sharp, and you cannot run that much crank lead on 93 octane. 4 degrees is actually around where 93 won't rattle with that much compression, but you lose so much response and power it's sickening. And they need a quick advance curve--36-38 degrees total all in by 2500. I was talking about fine-tuned ultimate performance, not getting the engine to live on the crap gas we have today. Those engines were designed when you could buy 102-octane Sunoco 260 premium with real lead at the pump for 30 cents a gallon, and they were jetted fat, not lean. A DZ 780 Holley was calibrated to run rich--72 primary jets are not lean..chuckle. Try this; buy a tank of high-octane racing gas and bump your initial timing up to 10 degrees, then flog the car. I believe you'll be amazed at how much more responsive and free-revving the engine is, and how much more crisp it is. And you'll be delighted at the extra power turned loose. I may sound like a dinosaur, and I guess I am, but this is how they were tuned back in The Day, and those 302s screamed like banshees when unleashed on good gas. Just my humble input from a guy who was there. Good luck.

HotRod'68  1968 SS350 coupe undergoing frame-off resto/rod. 386/350/4.11s
Butternut Yellow    black standard interior

lakeholme

  • Hero Member
  • *****
  • Posts: 2256
  • 68-12D L30/M35
    • View Profile
Re: av gas yes or no
« Reply #16 on: June 24, 2007, 12:26:12 PM »
to run in a stock 68-302 car.

But the original question was about "stock".  And for those of us who were around back in the day, "stock" seems to mean something different today as well...
Phillip, HNR-AACA, Senior Master, Team Captain
Charlotte Autofair, Sept 24-27, 2015
Southeastern Spring Meet Chair, April 9, 2016
Sentimental Tour Host, June 12-17, 2016

GaryL

  • Hero Member
  • *****
  • Posts: 538
  • Marilyn and me
    • View Profile
Re: av gas yes or no
« Reply #17 on: June 24, 2007, 06:25:33 PM »
Stock to me for a DZ engine is 11:1, 30-30 cam. Yes it is overbored .030". Original 186 heads with no porting, polishing or hard seats, original intake, points distributor. Stock primary jets were #68. The factory set these engines up to run lean and hot for smog to run the AIR system. I have #72 primary jets, 36* at 2800 rpm and full vacuum advance. These changes are only good tuning, still considered stock and what many 302 owners do to their engines. I will repeat it runs strong and good. Gas is gas. The only difference is octane rating. Higher octane does not produce more power by itself. You could not use a modern fast ramp cam with 11:1 and get away with this. :)

JohnZ knows his stuff!

« Last Edit: June 24, 2007, 06:29:55 PM by GaryL »
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

Jerry@CHP

  • CRG Member
  • *****
  • Posts: 1457
    • View Profile
Re: av gas yes or no
« Reply #18 on: June 25, 2007, 11:58:34 AM »
Have used Av gas since the 1970s.  It's good stuff and I still use it in my own personal cars. I even used it in my stock eliminator race car until NHRA banned it in favor of using fuels that they now accept.  Car ran the same ETs with Av gas and the high dollar VP and Sunoco fuels.

I add about five galllons and then fill the tank.  Also works great if you car is going to sit. 

I have found that the over the counter additives eat away at the carb parts.  They are not user friendly to the internals of your carb.  I have many customers who are living proof of this issue.

Jerry

JohnZ

  • CRG Member
  • *****
  • Posts: 4278
    • View Profile
Re: av gas yes or no
« Reply #19 on: June 25, 2007, 01:48:43 PM »
I have found that the over the counter additives eat away at the carb parts.  They are not user friendly to the internals of your carb.  I have many customers who are living proof of this issue.

Jerry

Very true - the "octane boosters" like 104+ are LOADED with alcohol, which eats the plating off the inside of the float bowls and metering blocks, then its affinity for mositure goes to work on the now-unprotected surfaces and corrodes them. A friend of mine who has rebuilt Holleys and Q-Jets for decades has seen this for many years on carbs that have been run with 104+.
'69 Z/28
Fathom Green
CRG

bertfam

  • Hero Member
  • *****
  • Posts: 2333
    • View Profile
Re: av gas yes or no
« Reply #20 on: June 25, 2007, 02:56:24 PM »
Okay, so if 104+ shouldn't be used (or any other octane booster for that matter), what do you guys recommend for people that don't have access to avgas???

Ed

jdv69z

  • Hero Member
  • *****
  • Posts: 739
  • 69 RS Z/28 52E
    • View Profile
Re: av gas yes or no
« Reply #21 on: June 25, 2007, 02:58:00 PM »
Would this be true as well for fuel additives/octane boosters from manufacturers of racing gasoline products? Eg VP or Klotz, etc.?

Jimmy V.
Jimmy V.

GaryL

  • Hero Member
  • *****
  • Posts: 538
  • Marilyn and me
    • View Profile
Re: av gas yes or no
« Reply #22 on: June 25, 2007, 08:24:41 PM »
Okay, so if 104+ shouldn't be used (or any other octane booster for that matter), what do you guys recommend for people that don't have access to avgas???

Ed


How about this.  http://www.hi-flow.com/HPOP5.htm
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

Jerry@CHP

  • CRG Member
  • *****
  • Posts: 1457
    • View Profile
Re: av gas yes or no
« Reply #23 on: June 26, 2007, 03:36:11 AM »
Find the closest small mom and pop airport to you.  Buy three or four of the Jegs five gallon fuel jugs and go there, fill them up as needed.  Four jugs will last you for four tanks of gas.  That way you're not running back and fourth every week.  I have six of the Jegs jugs.

Jerry

fireZ

  • Hero Member
  • *****
  • Posts: 548
    • View Profile
Re: av gas yes or no
« Reply #24 on: June 26, 2007, 11:57:32 AM »
Sounds good to me I can buy it at the local airport without any trouble.
1968 Z28 LA Built
LIC # RPO Z28

sd1968z28

  • Member
  • ***
  • Posts: 258
    • View Profile
Re: av gas yes or no
« Reply #25 on: June 26, 2007, 03:25:13 PM »
listen to jerry guys, good gas make these cars scream!!!!!! i run my car 5 gallons of race gas per fill and it works!!!

fireZ

  • Hero Member
  • *****
  • Posts: 548
    • View Profile
Re: av gas yes or no
« Reply #26 on: June 26, 2007, 03:43:30 PM »
I went and bought 5 gallons of 100LL AV gas this morning and boy did the car run better. I thought it was good on pump gas but now it is a different animal. Thanks Jerry
1968 Z28 LA Built
LIC # RPO Z28

GaryL

  • Hero Member
  • *****
  • Posts: 538
  • Marilyn and me
    • View Profile
Re: av gas yes or no
« Reply #27 on: June 26, 2007, 06:56:16 PM »
Now I am thinking I will try it.
Gary

Lemans Blue X33. DZ, M20, manual steering. Only BU code rear end is original.

Pacecarjeff

  • Member
  • ***
  • Posts: 344
    • View Profile
    • Jeff's Cars
Re: av gas yes or no
« Reply #28 on: June 26, 2007, 07:14:49 PM »
Okay, so if 104+ shouldn't be used (or any other octane booster for that matter), what do you guys recommend for people that don't have access to avgas???

Ed


I use 110 leaded racing fuel. half and half 110 --- 93
It is available from the Sunoco station down by the everglades boat stations
$5.75 a gallon. pump straight into you tank.

Don't run straight 100LL AV gas in your car-- the burn rate is wrong -it must be mixed

sam

  • Member
  • ***
  • Posts: 232
    • View Profile
Re: av gas yes or no
« Reply #29 on: June 26, 2007, 07:19:45 PM »
How about buying 5 gallons of VP Racing gas from the  Farm and Home Center and mixing it with 93 octane to fill your tank up. Its about $5.00 a gallon. As good or not as good as the AV gas?  Sam