Carb / dyno tuning in SoCal?

[3literpwr]

Well, my car is together and put about 20 miles on the engine. Seems to be running good, but a little stumble / roughness from 2-3.5k. After that, it screams. Can't believe the noise this thing makes now! Would like to get it on a dyno and get it dialed with timing, jetting and the like. Anyone in the LA area know who to see? I'm actually in Ojai, but will travel as needed.

Engine is a 3.0 with twin plugged, large port head (flow benched), DC60 cams, 10.6:1 comp, PMO 46's (William Knight), arp etc. etc. Gearbox is SCRS geared, so 5th is 1:1.

[Trackrash]

Here is all you need IMO.

PCA has used JBA Speed Shop in San Diego. Not sure if they still have any Weber experts.

[3rd_gear_Ted]

Club racing guys need a HP chart for club competition director to have on record, they go here a lot.
Aase Motors is nearby too for tuning.
Superior Automotive Engineering - Dyno Tuning Los Angeles - High Performance Automotive Services

[CBA]

Aase handled my 46 PMO's. The are some of the nicest guys in the business and do excellent work to boot.

[Cory M]

Same here. When I had pmo carbs and had a bunch of issues I took them to Jeff at AASE. They tuned the carbs on the dyno and identified and repaired a few other issues.

[3literpwr]

Thanks folks. I think i'm going to start with the AFR and get as dialed as I can, then take it to see what she makes and maybe swap exhaust or other mods there.

[targa72e]

I will second the wide band to check AFR. You can then check AFR by driving around. You can have a fairly wide mixture range that makes the same power. Once mixture is dialed in you can play with timing on the dyno to find best safe HP.

john

[chiroracer]

What is a good lambda sensor gauge setup available? One should have a sensor on each bank ,no?
I will not mount it permanently but just for tuning.

[Evan Fullerton]

I run an innovate AFR gauge in my MGB with a Chevy 60 Degree V6 swap with a Holley 4barrel. They have several different options depending on how you want to log the information.

Ideally 1 per bank is good, or for even better info, individual cylinder EGTs and 2 or mor lambda sensors is the best info. Individual EGT will let you know when you have a clogged jet which is somewhat of a common experience with carbs in my experience.

If you have a lambda sensor per bank, that will tell you when one bank is running rich of lean but individual cylinder EGT will tell you which cylinder has the fuel or spark issue.

[Jonny042]

I would second the sentiment that you're better to tune it to AFR and maybe visit the dyno for fun at a later date once you think you have it sorted.

I like to keep it simple - single AFR and keep a close eye on the plugs to make sure everything is looking even. Mind you I have MFI and once the pump is setup it's pretty bulletproof from a fuel delivery/distribution standpoint.

Innovate sometimes gets a bad rap for doing things like eating sensors but mine has been through two driving seasons of hell with me getting the tuning and space cam mods done on the 3.2SS MFI.

I have one of their MTX-L plus gauge/comtrollers, an SSI-4 logger so I can log RPM and throttle position, and a pocketlogger which puts the data on a microSD card.

The logging is really fun. One useful thing it allowed me to do is compare ****ing times between Swepco 201 (1.000+sec.) and Motul Motylgear 75W90 Technosynthese (0.600 sec.) All the logging stuff is in my build thread. Here's one example:

Originally Posted by Jonny042

What a difference a few days makes!!!

Before:



And after:



The comparison between the two lines isn't all that easy - it doesn't help that I've been playing with the main rack adjustment, the leverage ratio, etc AND doing a little material removal in the 5500-7000 rpm range - this second round of space cam grinding was a definite success and I can confidently say a few things: One, the car has never run better!!!! And Two, it's almost there!!!!

I have a really annoying lean spot on trailing throttle coast-down that is downright embarrassing but should be easy enough to "grind off" on one of my rounds of pump removal and space cam modification.....

I must apologize - I've been meaning to take pictures of all this but keep forgetting.

On interesting thing I did yesterday was a volmetric test on fuel delivery at max delivery which was occurring right around 5700RPM and measured out to be about 66ml/1000 strokes. Today the grinding I did on the space cam increased this delivery in the 6000-7000 range (but focusing on the 6300-6400RPM range) in the hopes of taking out that bump in the AFR curve.

According to my rough calcs the fuel delivery in this range is now 69-70ml/1000 strokes.

More tests to follow, but this exceeds my projected fuel demands by quite a bit, and is close to that of the factory 2.8 RSR pump.

Fun stuff!!!

[Trackrash]

If you post the details of your carb setup, I'm sure the experts will chime in with opinions on your jetting.

Performance Oriented Has a ton of info on setting up webers on 911s. Hosted by Paul, aka 1QuickS here.

[Tremelune]

Originally Posted by Evan Fullerton

MGB with a Chevy 60 Degree V6 swap with a Holley 4barrel.

Just so everyone knows...these are cool...

[Evan Fullerton]

Originally Posted by Tremelune

Just so everyone knows...these are cool...

I don’t know about THAT cool…… but they are much cheaper. Haven’t dynoed it but feels like 180whp but she is all done by 6000 RPM and T5 gearboxes aren’t all that. The whole performance engine build was less than the P&C for my 911 though so there’s a reason one is done and the other isn’t.

[targa72e]

I built a MGB with a 4.3 Chevy and 4 barrel holley tied to a turbo hydomatic may years ago. It was quite fast.

john