9:8.1 Ok with 91 Octane?

[arnolds64]

Going to an Engle 130 for my Weekend Bug - 2017 -40 x 35 P& P'd Chambers Opened Deck will be .045.

Will 9:8 C/R work with 91 Octane. Live in KC Missouri.

[skeeter!]

I have 9:1 CR and I run 91 octane in a car with an Engle 110 cam and 42x37 valves, dual springs and 1.25 rockers...

[neil68]

Since you're at ~1,000 ft elevation, I'd say you're probably fine.

I ran 9.6:1 CR at 2,200-3,300 sq ft with W120/1.25's and also FK8/1.4's and Web 86C at 10.5:1 CR with no problems on 91 octane.

You could always use 92 or 94 octane, if pinging can't be tuned out...

[John P]

There isn't a lot of margin built in there. Do you plan to drive at sea level?

I'm running 9:1 at sea level with a K8 and 1.4s, and it's fine but I doubt that I have much room left.

But I'm conservative...

JP

[maui]

My old 2176 with E130x1.25s had 10+1 on 91 super at sea level for a few years with no problems.

[John P]

My old 2176 with E130x1.25s had 10+1 on 91 super at sea level for a few years with no problems.

I'm blown away that you could get away with that at sea level. What was your total advance re: ignition timing?

[Chip Birks]

I ran 10.5 to 1 with welded 42x37.5 041s, fk8 with 1.4s. 2276, but I'm way up high in Utah at 4500.

[superdrag]

If it were me, I would run a mix of 91 and 110 at 9.8 to 1.

[John P]

Yeah, I'd be worried too about being close to the edge at 9.8:1 if you plan to go down to sea level.

But clearly some guys here are doing it, but there must be little margin for error.

My 1.5 cents.

J

[maui]

I was running F/F heads with 42x37 and butterfly chambers and a 050 with pretronix ignition and MSD wires at 32 total and 32 plug gap. Then a few years ago I went to a DUI dist. and MSD wires and 32 total and 45 plug gap. My 48s had f10-70x165x190xF7 with 42 vents with no 3rd hole and ran smooth and loud with 1 3/4 headers and 3in flowmaster. It had 3.55x2.07x1.56x1.13x4.37RP.

[John P]

Impressive.

[Dave Conklin (Cornpanzers)]

I ran 9.8:1 for years with no problems on 92 / 93 octane unleaded.  Cam was an FK-8 with modest overlap so the actual running compression was probably a touch more than if you are running a bigger cam. 

[Joel Mohr]

It depends on the cam and chambers....I'm running 10.3 to 1 on 91, with Hemi cut chambers and a special grind by Web that's .640 x 310.....no deisel, no ping, and 32 total advance......next test will be 11 to 1. Yaris, (Toyota) has a new motor that runs 13 to 1 on 87 octane.....

[maui]

My chambers are shallow and very open almost like a Hemi but shaped like a butterfly with the plug for the head. It's also 30yrs old and I don't know if anybody makes um anymore but it works good.

[VW NOT V8]

It depends on the cam and chambers....I'm running 10.3 to 1 on 91, with Hemi cut chambers and a special grind by Web that's .640 x 310.....no deisel, no ping, and 32 total advance......next test will be 11 to 1. Yaris, (Toyota) has a new motor that runs 13 to 1 on 87 octane.....

The 1NZ-FXE is the earliest 1.5 L (1496 cm³) version built in Japan. Bore is 75 mm and stroke is 84.7 mm. It features forged steel connecting rods and an aluminum intake manifold. The engine has a high physical compression ratio of 13.0:1, but the closing of the inlet valve is delayed. The net result is that the engine has a greater effective expansion than compression—making it simulated Atkinson cycle, rather than the conventional Otto cycle.

The reduction in cylinder charge means reduced torque and power output, but efficiency is increased.

reference.... http://en.wikipedia.org/wiki/Toyota_NZ_engine#1NZ-FE

Have fun !!

Chris Andrews - The Mailman

[arnolds64]

My chambers are shallow and very open almost like a Hemi but shaped like a butterfly with the plug for the head. It's also 30yrs old and I don't know if anybody makes um anymore but it works good.

I am going from a 110 Engle to the 130. I had 60cc chambers before that were like a Hemi Cut almost. It sounds like this works as mentioned by a few of you with the cam and C/R? Here is  pic link of the heads chamber.

http://img222.imageshack.us/i/1002046h.jpg/

[maui]

I also forgot for mention is wen I ran 100 deck to lower my comp. it would ping alot. so I posted it on here and a guy named George Brown told me to make my deck 60 even if the comp went up to 10+1 so I did and the ping went away and with proper jetting it ran cooler and way better. He told me that open chambers need a good deck or it will ping and he was right.

[DANTHEMAN]

He was a big part of my VW education, learned a lot, will never forget him

[arnolds64]

Anyone ever comment on the chambers and how it will run? What did you all start your jetting at? I am going 55 idles and 145 mains with 180 airs. Think this is safe?

I am calculating the 9.8.1 with a .040 - .045 deck too. Ran that with my 110 and these heads but I also took out .060 with a Flycut to bring up the C/R. So they are much shallower and sounds like I am on track with the chamber, according to you all?

[maui]

Don't know about you but I run 48s and 42x37and F10-70 idle and 165Mx195AxF7 and 42vents and 60 deck and 50cc chamber and I think it was 100 fly cut.

[65bug]

I run a 2165 w/ Tims stage 2 heads. 48 DRLA's and a Pauter 550 lift at valve cam/ 268 intake/exhaust.
   Compression is 9.7-1 and motor is ran on California 87 Sams Club gas. Motor runs cool as can be, no problems at all......