BritishV8 Forum

General Category => Engine, Transmission, & Rear Axle assy. => Topic started by: 88v8 on August 05, 2023, 05:11:54 AM

Title: Performer / AVS2 4bbl, tune compared.
Post by: 88v8 on August 05, 2023, 05:11:54 AM
Removing the 500 cfm Performer from my 215 Rover V8 because of ethanol crap, and replacing it with a 500 cfm AVS2.

In this  (http://forum.britishv8.org/read.php?6,70181,page=2) thread I recorded the Performer tuning setup, and I assumed I would just be able to swap the tune into the AVS, but nooooo.

The out-of-box of the Performer is 086 primaries with 65/52 rods, but the AVS has 095 jets with 70/52 rods, which is 30% richer on cruise and 35% richer on power. Presumably there's a reason for that, so I shall have to get out the AFR meter and start again.

Also, I'm not sure that I can swap the accelerator jets... are they a different design... Edelbrock's website has me tearing my hair.... it's pouring with rain atm so I'll go down to the garage and check later.

And the AVS has an autochoke, I never ran an autochoke, we'll see how that goes.

Anyone done the Performer / AVS2 swap?

Ivor
Title: Re: Performer / AVS2 4bbl, tune compared.
Post by: MGBV8 on August 06, 2023, 01:24:57 PM
No.  Been using my Carter/Edelbrock 500 for 22 years now.  Often with E10.  No issues.

Out of the box jetting is for an assumed larger engine.
Title: Re: Performer / AVS2 4bbl, tune compared.
Post by: 88v8 on August 08, 2023, 04:40:46 AM
I asked Tech Support why the fatter jetting, the reply was it's related to the annular booster... which makes no sense.

So yesterday I put the carb on the engine, created the wiring for the autochoke where I used a relay given it can apparently spike at 10A, and I swapped in the tune from the Performer with the exception of some fatter rods because I'm being cautious and I can easily swap in the current rods at the roadside if my AFR meter gives me the OK.

Unfortunately it's raining (again) all day today so I will have to wait until tomorrow to start it up, given the car is 'garaged' outside.

I presume despite the autochoke I still need to prime it with a couple of squirts?

Ivor
Title: Re: Performer / AVS2 4bbl, tune compared.
Post by: MGBV8 on August 08, 2023, 09:13:47 AM
Try it without first.  Didn't want the manual choke version?

I have never had a choke on mine. I just turn on the key, listen to the Carter fuel pump for 7-8 second, pump the gas 3 times to the floor, then start the engine with my foot off the gas.
Title: Re: Performer / AVS2 4bbl, tune compared.
Post by: 88v8 on August 09, 2023, 01:04:04 PM
The manual choke on my Performer started up OK, but then I had to juggle it two minutes or more in the winter, before I can drop into Drive.
I didn't particularly want an autochoke, but on eBay up pops this 500cfm AVS2, low mileage the chap said, and it happened to have an autochoke, and it was $$ below retail, so.... now I have an autochoke.

Two pushes on the throttle, it started right up. Set the fast idle. I could drive it straight away, no juggling, which is nice.

Out with the AFR meter to see what's what.
Can I simply transfer the tune that was in the Performer....?

Well, the 7057 rods I had in the Performer gave around 16/17, too lean, so the answer is No.

Tried 7042, 6852, then 6755 which run at around 14/15 and 11/12 at WoT so that's fine.

In my OP, I was talking nonsense about the squirters, I misunderstood the annular thing, the squirter nozzles are the same as the Performer so I transferred the 024s, rod in the bottom hole. No bog off idle, if anything it's fat.

So that's it:
083/080 jets
6755 rods
Orange springs perhaps
024 nozzles.

I haven't adjusted the secondary air valve as there's no spike going into WoT.

I just need to look at the transition springs, I see a cruise/power spike on the meter, may go back to that tomorrow.

Ivor
Title: Re: Performer / AVS2 4bbl, tune compared.
Post by: MGBV8 on August 09, 2023, 02:23:59 PM
https://www.motortrend.com/how-to/1908-inside-look-new-edelbrock-avs2-carburetor/
Title: Re: Performer / AVS2 4bbl, tune compared.
Post by: 88v8 on August 21, 2023, 08:04:57 AM
Yes, an interesting Motortrend article there or is it an infomercial, anyway I agree the throttle response is really sharp compared to the Performer..
Not that one notices too much when driving with an auto but still....

Ivor
Title: Re: Performer / AVS2 4bbl, tune compared.
Post by: MGBV8 on August 21, 2023, 10:23:49 AM
How much vacuum at idle, Ivor?  Those orange springs tend to be a bit weak for an engine with a lot of vacuum.
Title: Re: Performer / AVS2 4bbl, tune compared.
Post by: 88v8 on August 24, 2023, 04:34:13 AM
13 inch on the manifold port.
270 cam, never made much vac.