What are the Pro and con of removing the Twin AIR on a 89 P30

[tmsnyder]

Don't ask me, the running consensus here is that I'm nuts and am going to blow it up!    


It might be good to run it stock for a while and get some mpg numbers etc. 

I didn't do that, and installed pre-1970 stock timing using an aftermarket, manifold vacuum advance and mechanical advance and but have no baseline numbers, will post results when I have some.  At this point I just know it runs good and sounds good. 

It's pretty easy to do later on.

THANKS it seemed like it took for ever. no i havent  adjust the timing yet . I wanted to run it at the stock setting. Do you think i should? if so what should I set it at?

[crd]

What mpg?

8.4 mpg

[crd]

We all are a little nuts...   I did buy a crane adjustable vacuum advance however I havent install it yet. That is were I am it..It runs great, starts good and sounds really good. I dont think i am going to change anything else for while. We are going to put some miles on it and enjoy it. We are planning on taking it to Alaska next summer.

[tmsnyder]

8.4 seems great.  I get about that in a suburban towing a small travel trailer.

With the stock timing and ported vacuum, it's probably calling for 4 degrees btdc right?  Since you changed the cap and rotor you should check and make sure it didn't move, plus you never know where the previous owner had it set.

[tmsnyder]

Did you leave the EGR valve functioning?

[crd]

I disabled the egr. I plan order a delete plate from summit racing.

[Rickf1985]

8.4 seems great.  I get about that in a suburban towing a small travel trailer.

With the stock timing and ported vacuum, it's probably calling for 4 degrees btdc right?
  Since you changed the cap and rotor you should check and make sure it didn't move, plus you never know where the previous owner had it set.

You are constantly referring to Ported vacuum! I want you to go look at the vacuum diagram on your air cleaner for the emissions system for your engine. You will see That the distributor advance is on manifold vacuum run through the TVS and a VDV. I am not going to explain all of the technicalities of the acronyms because you obviously know what they mean. The distributor is on MANIFOLD VACUUM STOCK!!!!! If yours is not then someone changed it. In your favorite Camaro magazines the big blocks from way back then WERE on ported vacuum. That was the way to go on drag engines. I am sure I am going to get blasted by the site owner for pointing this out but please stop giving out bad info until you learn how these engines are properly set up. All you are doing is confusing people by telling them they have a setup that they do not have.

There are some modifications that can be done as was pointed out by Jim several years ago that you want to try, Fine, try it and let us know. I notice you did not start out at the timing advance you wanted us to start out at though. Do not point out what others "Should" be doing until you have done it and quantified it yourself.

[tmsnyder]

Rick, I'm not the one with the pinging engine, brother, that's you.


Big picture point is; the setup under the cap has to match the vacuum source.  His may be on manifold right now, it may be on ported, I don't know b/c it's not mine.  You say it's on manifold vacuum already, that could be. 


The sticker on my air cleaner is illegible, but it doesn't matter to me b/c the stuff under the cap is no longer original.  I put it on manifold vacuum, with a vacuum advance can to match it, and a mechanical advance to match both.  I originally planned to set timing at ~12 initial, 23 mechanical, and 14 vacuum.  Yes, I backed that down to 8 degrees initial based on advise from you that there would be pinging problems.  There were none so I have since increased the initial timing several degrees and increased the vacuum timing to 18 degrees.

As I wrote the OP earlier, if I were him I'd run it as-is for a while to establish a baseline.  8.4 mpg seems great.  Recurving the distributor might be something to try down the road a bit since it is easy and cheap to do, and the 4 deg initial timing is a dead giveaway that there's some lousy smog-based timing setup under that cap.  There's probably some room for improvement there, both in mpg and hp.

What is it with you and camaros btw?       Get it right, man, the Timing 101 article I shared was originally written for a Corvette magazine.  It's a great piece, you should read it.

[Rickf1985]

John Hinckley and I and a few others discussed him writing that article before he even wrote it. And yes, it is a very good article. I have built many motors in the past up to 1250 horsepower blower motors running pump gas. And up to 1550 horsepower on alcohol. These are dyno proven figures. I know just a bit about timing and performance motors and I also know the author of that article.
I am not trying to say you do not know what you are doing nor am I trying to put you down. I am trying to get you to realize that you are talking to a captive audience that trusts what you are saying and you need to get the facts right before saying them. Get the original configuration of the engine right before you offer modifications so that way people do not get confused when they get into their engine and things are not what you suggest.

I am not going to say anything more on this subject on either of the threads you have running.
It is turning into a pissing match and that is not what I want and definitely not what Oz wants.

[Oz]

That's correct.  Agree or disagree, prove or disprove, but keep it impersonal and as a matter of technical points. 

[Rickf1985]

I am in the process of doing this right now now and testing it out with some runs. I will pass on the results once I get enough info to do so. Right now I am at 10 degrees initial, 23 mechanical starting in at 1,000 RPM and fully in at 4,000 rpm and 10 vacuum on full manifold. runs fine with no pinging under load at WOT or at cruise. Will be bumping the vacuum advance up to 15 degrees. will have to wait for some cooler evenings since the testing has to be done with the engine cover off to be sure I can hear any pinging. It was 148 degrees in the RV on the last test run! My test runs are a 20 minute loop, anyone want to ride along?

[Oz]

I really would love to ride in a vintage RV again.  Any vintage RV.  I miss mine - may it Rest in Pieces.


Hey crd & tmsnyder,


Please use the reply button on the topic rather than the quick reply under the page.  The quick reply always quotes the previous reply and that just adds unnecessary text since most replies are made to the latest response.  Use the quote button on the topic when you are quoting something from an earlier post other than the last post or if you want to reply to a specific statement or statements made in an extended post which would otherwise be difficult to understand without it.

[Rickf1985]

I don't think you are all that far from me, I can come out your way and pull the engine cover for the next test ride. :)rotflmao :)rotflmao :)rotflmao

[WrigleysBraveWin]

With the exception of the cross over on the exhaust Gone has same set up except Banks vs hedmans... AVG is about 7.4... got 7 last tank but did have the genny running for several hours, roads mostly flat.. she likes about 50-55mph... no toad. 13,800 lb with about 60 gal of fuel and empty water tanks.  Tiffin has tubular aluminum coach frame so a bit heavier than the wood framing.

Have Banks on my 23’ Chevy Brave and have gotten up to 11.6 mpg but average over 10.2