whats the highest compression engine youve built??

[BFB]

seems like we need some more actual performance posts, so... whats the highest compression engine youve built? and maybe throw some specs in, and what fuel you run.

mine was just 8.8:1 1641, but most of mine are turbo. most ive boost so far though is 20lbs through stock 1600 on 91octane.
currently running 2276 8:1 cr , 12lbs of boost on 91

id kinda like to build a high compression n/a though and have read ppl have trouble going past 9:1 on pump gas

[King_vw61]

2783cc Autocraft case with 910 heads 10.8cr. I use 91 with torco octane boost. 600 street miles on engine so far, still working out the "Bugs"

[67rustavenger]

2180
Webcam 86b
Tim's stage II heads
9.4:1 cr
45 DLRA's
Low octane pump gas. Normally.
The car did 14.413 @ 91.7mph June 1st. Used High Octane for this run.
_________________
I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!

There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo!

[oprn]

1737 cc water pumper, 9.5 CR 15+ psi boost on propane (120 octane equivalent). 10* pressure retard. Started to ping at 12 psi at 70*F ambient. 18 psi no ping at -30 ambient.

Presently running 1911 type 4, 8.4 CR N/A on 87 octane. No ping found anywhere. Regret not taking CR to 9.5!

[jpaull]

10.5:1 is easy when the cam is bleeding off a little. No pinging on 91 pump gas
_________________
[email protected] MPH 1/4 Mile & 8.1 @ 83.7MPH in 1/8 Mile with Mild Type 1 VW Mag Case 2234cc commuter engine in stock weight bug w/only .491 total lift(CB2292 Cam), 42x37 heads, 48idf's, Street tires, Belt on, Mufflers, Pump gas, video of the run here: https://youtu.be/M3SPqMOKAOg

Transmission by MCMScott:
Rhino case, Klinkenberg 4.12, Superdiff, 002 mainshaft with 091 first idler. Weddle 1.48 Third & 1.14 Fourth.

[slalombuggy]

Brutus:
12:1
2332cc
Ultra Wedge Ports
Web 251
51mm EPCs
CB Aluminum case
VP C-12

Little Brutus:
10:1
2332
Wedge Ports
Eagle 2290
48 IDFs
Another CB aluminum case
Shell Gold 91 with octane boost.

Baby Brutus
9:1
1904
Revmaster 049s
Engle 110
40mm HPMX
AS-41
Shell Gold 91


brad

[Stripped66]

2276, AC.net Super Squish pistons, Pauter vn119 cam, 12:1 CR, 93 octane.
_________________

[Mikedrevguy]

2276
Comp eliminators 48/40
FK-98
12.7:1
_________________
74 1303 (RevBug): plan for German Look
76 914 with 2260
79 VW Iltis
69 Bwajaja
"The wise speak because they have something to say; while the foolish speak because they have to say something." Plato

Illigitimi non-Carborundum!!

[modok]

21-1
Do diesels count?

[vwracerdave]

2165cc
Street Eliminator heads
FK-10
11.2 CR
Mix 1 1/2 gallons 110 race fuel with 3 1/2 gallons 91


1425 Lb W/driver Dunebuggy ran 12.20's
_________________
2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
2010 Sportsman ET Champion - Mid-America Dragway - Arkansas City, KS
1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK
Featured in Dec. 2001 HOT VW's Magazine page 63

Watch my racing video's http://www.youtube.com/user/okvwracer/videos

[Howard 111]

13:1, but it was a drag only Ghia. 7.57 at 90mph in the 1/8 mile. Fun car, especially against the V-8s.
_________________
1973 Karmann Ghia
Turbocharged, Fuel Injected
http://www.thesamba.com/vw/forum/viewtopic.php?t=531270

[bugguy1967]

You asking about static compression, so 10.5:1 on a W130 on 91 octane at sea level. But I’ve built engines with more actual running compression than that.
_________________
"A petrol engine can start readily, run smoothly and give every appearance of being in good order, without necessarily being in good tune." - Colin Campbell, "The Sportscar Engine"

[BFB]

thread is going great , lotta good replies. lets not ruin with going down the static vs dynamic road

[jeffrey8164]

2276
8.7:1
With no additional work my parts config gave me 9.5 static. I thought that was a little high so I added 6cc to my chamber volume.
Not he highest obviously but I don’t want to have to find or carry race gas when I just want to cruise the mountain roads.
There are two different CRs so if you only want one you should be more specific in your questioning.
_________________
Volkswagen!
Turning owners into mechanics since 1938.

“Let he that is without oil throw the first rod”
(Compression 8.7:1)

[HotStreetVw]

The last engine I had in my split was a 2275 that I tried to follow the Pro Gas class rules. (PG legal heads). Few exceptions, I ran a 82 crank and 51s because it’s what I had. Rules allow for 84mm and only 48s). I also had more welding on the manifolds (let’s call that SS/VX legal )

The teams of JackS and Klink set the bar for 44mm intake performance, so you pretty much know what the engine platform is capable of. If your going to chase someone, chase the best.

I built it with 38cc in the heads and valve reliefs and .040” deck with a static CR of 13.6:1. I ran it on VP110.

At bandimere the car would run 11.9s and 12.0s. (Track is 5800’ asl, and DA on a good day is 7000’ and always getting worse). It ran 11.71@114 in SLC, so even a small change in elevation, 4200’ asl, makes a serious difference. I’d guess it would have been a 11.5 or better car at your typical west coast track. Still a long way from the bar set by the best.

Power difference is obvious. Maybe 25hp. The other component is the driver and how hard they will push the car. I’d leave the line at 6800, but I’m pretty sure those guys are 8k+.

Compression is your friend. It makes for a nasty, raspy throttle and you know it’s alive back there.
_________________
4inBhore
50 Split - 2724cc NA. Haltech injected
62 Notchback - 2542cc Turbo WIP

[67 Sunroof]

What causes the higher compression? Not to derail the thread but was curious.
Is it a tighter piston to head clearances resulting in a tighter “squish” area?
So the higher cr would result in faster detonation as opposed to a lower cr?

My other car ran a high cr but we used an msd retard box at first and then a J&S retard box to eliminate the detonation. The J&S was fantastic. It had a small “microphone” that plugged into the block and would only retard when it “heard” pinging. Very slick.

[bugguy1967]

[Steve Arndt]

My 91 pump octane 2275 is at 12.2:1 right now. I ran 12.8:1 for a while with a bigger cam. Super squish pistons (set #1 been in it for like 15 years). 86A webcam. It has TONS of cranking compression.
_________________
Steve
Steve's 87 Syncro project

[mcmscott]

1584cc 13.5:1 class 11 race engine.
_________________
There are no stupid questions, only stupid people,

68 Ghia
67 T-1
65 Notch
02 Mexican beetle
74 Thing
15 Long travel rail
07 Nomad
05 f-250

[mark tucker]

for vw 11.5, for small block mopar 14.3.