289 FIA vintage race engine with Webers
 

Greetings,

For those of you who have not been following my build thread on the Superformance Riverside Racer FIA vintage race car, due to the need for a rebuild I decided to go away from the Holley 4 barrel and install a Jim Inglese 8 stack Weber system to see if that would improve race performance. That meant, not only ditching the carb and manifold, but also having to go with a different cam as the one in the engine had 106 degrees of lobe separation. Jim suggested that I use Darryl Fitzgerald in CT for the build, as Jim had taught him about Webers and had used him on many builds. When I dropped the engine off at his shop in the fall, there were 4 engines with Webers on them in various stages. He as building a small block for a Daytona replica and he had another small block that he was installing in a Kirkham 289 slab side.

Well the engine was finally done and I drove out there today to do a couple of pulls on the dyno and take it home. Darryl had called me yesterday to let me know the engine would be ready. It has a custom ground Crower cam with an LSA of 112, Comp cam roller lifters and a stock crank. Due to vintage rules it has to have cast iron heads, i was allowed to use aftermarket Dart Iron Eagle heads, and original stroke. A slight overbore is allowed, I am at .030.

It was a fun day. Yesterday Darryl told me that they had gotten 370 HP and 330 ftlbs of torque on the dyno while tuning. A little less than what Expected, but still a nice number and in line with what the originals would have been running. During the first pull the dyno operator shut down the engine at 3500 rpms because it ws not making power. We checked out the engine and everything looked alright, valve lash was still good. Then we noticed that the attachment from the throttle on the dyno to the carbs was loose. It ws righted up and the next two runs provided consistent results. 424 HP and 362 ftlbs of torque!!:3DSMILE: Not too bad for a little 289 with iron heads and stock stroke. I can't wait to get it on the track.

http://www.clubcobra.com/forums/pict...=18259&thumb=1

Here are a couple of links to some videos of the last two pulls on the dyno. Crank up the volume and enjoy.

Https://youtu.be/Wgm3LMrQvPM

Https://youtu.be/rHo7ARK3_Xw

Jim

Boy that sounds really strong across the whole power band Jim. Lots of RPM too. That’s a lot of power from an old school 289!

Mike

That sounds like an understatement! Healthy figures there, with a very flat torque curve from 4500rpm.

Cheers!!
Glen

Ditto, to what Glen said. Call me during a moment of "down time" K? Cheers.

Jim,

Can you post both camshaft specs, and your Weber specs please, choke, emulsion tube, main, air, etc?

I would tried the Webers with the 106 cam first.

Gary

Gary,

First off, the engine has 12.5:1 compression ratio and is running on 110 race fuel.

Weber specs:

Choke: 42 mm
Idle Jet: .70
Idle Jet Holder: 1.00
Emulsion Tube F-11
Main Jet: 150 (we started with a 165 but it was to rich)
Air Corrector: 200
Pump Jet: .050
Acc. Pump Exhaust Valve: .45
Float Setting: 5.5 mm

Crower Cam specs

Intake:
Duration: 292 degrees
Lift: 6.06
Valve Clearance hot: In .016 Ex. .024
Rocker arm ration 1.6 both intake and exhaust.

Duration at .050":

Intake: 256 degrees
Exhaust: 266 degrees.
Lobe lift: Intake : .379, Exhaust: .375

Total advance ws 38 degrees (tried 36 degrees but the engine did not like it).

The builder thought thought that the 106 cam, with .640 lift was too much for the old engine with the Holley 750 and there is not much out there to suggest that Webers like that much LSA.

I was thinking about having a backup set of Main Jets just in case I start running too lean, what is the next size richer from the 150's?

Jim

Sounds amazing Jim. That torque curve looks great as well. Congrats on getting her built. Welcome to the wild and wonderful world of Weber carbs.

Byron

One of the biggest misconceptions about Webers is that they have to have a wide LSA. Even the factory cars ran 106 and tighter with Webers.

Jim, I think you're down around 50 hp from where you should be. The last 289 road race engine that I built made 20 hp/30 lb-ft more with less camshaft and factory cylinder heads that flowed around 200 cfm.

On next refresh, shoot me an email.

I am glad others feel the same way, ;).

Gary

Jim,

I'll give you a lengthy reply in the morning, now 10.30 AEDT.

Gary

Yes, throwing a big port Dart head on a small inch engine and then widening the LSA creates scavenging issues. A small engine needs a tighter LSA to help with a large intake port volume.

The Dart heads, even with a 180cc port volume, are still 30cc's larger than a factory head, which is a huge difference.

Major camshaft mismatch on that engine. A camshaft with mid 250's .050" duration and a 260cfm cylinder head should be peaking at around 8000 rpm on a 289ci displacement.

Would love to hear this raspy little beeeetch both idle and hit 8K. Gotta really bark with that compression :eek:

Brent and Gary,

Thanks for the input.

Brent, I will pm you when it is time for a refreshing, hopefully that will not be too soon. I understand what you are suggesting. At the same time, As a race car driver (as opposed to the engine builder) I want to go slow and this engine is a big step up in power. I have seen other racers have too much power too early in their development and it stunts their growth and can lead to bad habits, as power can make up for some of a bad line in a corner, but not totally mitigate it. By the time I am able to tame and feel confident with the handling and performance of this engine, I will be ready for your additional HP and torque. I also wanted a cam that would pul in the 4,000-6,000 range as I wanted more power coming out of the corners and was not as concerned with power down the long straights.

Gary,

Looking forward to hearing what you have to say.

I tend to be a sequential person and look to make slow and consistent gains. My race school was with a 120HP Formula Ford, first race car an MGB with 130HP, then increase the HP to 150 with the B. The cobra with about 350HP was a big step up from the B. Now I am ready for that next increase.

Karl,

Here is a link to the engine idling when it was on the engine stand prior to the dyno tuning.

https://youtu.be/LmPoRwlaL1M

Jim

Depending on your Vintage Assoc., SVRA, HSR, etc. the engine specifications may be determined by the time period the car represents. SVRA for instance has a Gold Medallion classification that determines cars to be period correct for their years(s) when they competed. 1795, are you limited in the total HP output in your particular classification and did you have your engine built to meet those guidelines?

I'd be willing to say that you had more horsepower before the freshen-up.

A set of Webers doesn't add horsepower by itself, they usually are down a few peak hp to a good single plane intake with the correct size carburetor. Any lack in mid-range power and throttle response can be cured with the correct camshaft.

Webers sure look cool, but they simply don't have the leg-up on other induction systems.

Steve,

Due to the fiberglass body, I cannot qualify for the SVRA Gold Medallion classification. The car has an SVRA logbook and runs in group 6. If you stay within the class specs, the real limiting factors are the carbs allowed, iron heads and your pocketbook, along with your desire to stretch the rules. see some cars out there that are definitely stretching the rules, but who really cares there is no financial gain for finishing first as opposed to last. I had my engine built to the specs SVRA requires.

Jim

Brent,

I am not so sure that the prior engine had this much torque. We will find out come June when it gets on the track at Mid Ohio. It will be a good test, some elevation changes, only one straight that you can get into 4th gear on, the rest if the course is primarily 2nd and a little 3rd gear. Appreciate the input.

Jim

I wish I could come and watch. It's the whole providing for my family thing that keeps me from it. LOL

Brent,

Come on up for a Saturday or Sunday. I'll put you on my crew list so you get in for free.

Jim

The rules governing the "Gold Medallion" cars are very strict, the car must be nearly an exact copy of the original in period car, including components and construction materials. The standard "BP Group 6" rules which apply to 289 Cobra based cars is very forgiving comparatively.

In the BP class as long as you run the proper displacement, conventional electronic distributor, iron heads and an iron block you can pretty much get away with most any other modifications you want.