Ignition Timing for 48IDA Webers

I order some Webers from Jim Inglese and I am excited to bolt them on this weekend. In his directions, he is very clear about setting the total advance timing to 38 degrees. I respect and appreciate Jim’s knowledge but I’ve also heard a lot of other people that disagree about this being a fixed timing for all engines. Though Webers do require more timing how much is too much? I’ve read some people stay around 30-32 and others go to 38 or 40 with no problems. Fuel and engine dependent I know, but I’m reaching out to those that have 8 stacks to see what y’all did. I have a 347 BPE currently running at 34 degrees total and got the beautiful 48IDA setup from Jim. Also Jim states that initial timing doesn’t matter for Webers, is this true?

Not saying I don’t trust Jim, just reaching out to see others thoughts and those who have them installed, Thanks!

Jim has been doing this for a long time, but I'm surprised at those numbers??? Small block fords like 12-14* initial timing for easier starts. 38* seems like A LOT of total timing. Have seen where 28-30* is the point where power starts falling off over that. That said, I have never set up a Weber carb system

^^^^What he said^^^^

I've had Webers and don't remember doing anything like that with the timing.

I think what Jim really meant is to set total timing, then idle will be whatever is dictated by the advance curve. As long as initial is within an acceptable range of let's say 10-20 degrees and it starts and idles good you're fine. If not you have to recurve the distributor. As far as total advance, that really needs to be tuned on a dyno. Compression ratio and combustion chamber design will dictate the total. I run 37 on my 347 with stack injection and AFR heads and 10:1. I dyno'd a 347 with TFS 11R heads and 11.5:1 compression and it only wanted 30 degrees. I have a 347 on the dyno right now with TFS twisted wedge heads at 10:1 compression. It wants 38 total. I would like to think Blueprint knows what their engine wants for timing. Hopefully this gives you a little more insight.

Bob

Bob, you have 37* set as max in the ECU, but has it ever actual dictated that amount of timing when driving the car? I think mine is at 34*, but have never seen that in actual use

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Originally Posted by rich grsc

Bob, you have 37* set as max in the ECU, but has it ever actual dictated that amount of timing when driving the car? I think mine is at 34*, but have never seen that in actual use

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I have a Holley ECU with a knock sensor. I've spent a lot of time tweaking the curve in normal driving ranges and have it pretty conservative under 4000 with load. I can lug it down to 1200 rpm in high gear and not get any knock. I've done a lot of data logging and it holds steady at 37 up to 7000 rpm limiter, doesn't pull any timing out.

Bob

I went back and reviewed some dyno runs. I started at 32 and made 460ish HP, went to 34 and it picked up, so I went to 36 and was getting 495, 38 and it hit 500, tried 40 and it stayed the same so I knew 38 was the Max. Backed it down to 37 and that seemed to be the sweet spot. Then I tuned the rest of the curve, but ultimately that had to be done while driving.

Bob

Yeah, sorry for any confusion, I am talking about total timing. I guess what I'm getting at is should I leave the timing where it is where the engine is happy from BP, or do I go with Jim's rec and adjust the timing curve up to give me another 4 degrees of total timing. I'm hesitant to do so because I am afraid of knocking and with my inexperience tuning webers not being able to diagnose the difference between the carbs being out of sync vs the timing being too high after install. I might reach out and dm some of the guys on here who have stacks installed. Thanks for yalls input so far though!

I'd leave where BP says to run it. You can always bump it up a bit once the car is sorted.

I agree w/ bobl. I have never run webers on an sbf but did a lot of playing w/ timing w/ a 4bbl. One thing I found out is that w/ side pipes, it is dang hard to hear engine knock. So I like staying conservative w/ timing advance.

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Oh my God.....what a pretty induction setup. Intuitively, I know that if I have to ask "how much?" I probably cant afford it, but....how much? (I went to the Inglese website but don't see any prices listed)

I would say Jim is the premium, I paid about $5,800 for his setup. A pretty penny but from what I’ve read, worth it in quality and performance. I’ll post more once it’s installed.

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Originally Posted by Goose

I would say Jim is the premium, I paid about $5,800 for his setup. A pretty penny but from what I’ve read, worth it in quality and performance. I’ll post more once it’s installed.

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Goose I agree. I think that setup is BEAUTIFUL and worth every penny. I want one some day. Its almost a shame to cover it with a hood.... :)

I have had 48 IDF webers on a 347 for a long time.

Total timing is at 34*, full advance at 2500 rpm.

Yeah, from everyone's input I think I'll keep it at 34 total but at least put the lighter springs on the distributor to get full advance as early as possible. Hopefully, we'll get everything on and working this weekend and be able to share some photos! Thanks again all!

I'm running stack EFI but it's still an IR setup like the Webers. Here's my spark table that seems to be working well and applies to what you're doing.

Edit, correct landscape graph now loaded.

Attachment 224593

Attachment 224600

SO the reason you have timing advance is gas burns a certain rate at all RPM. so to get peak cylinder pressure you have to light the fuel earlier to get that highest pressure at the same crank angle. Appox 10 deg ATDC. Now the chamber in the head defines this advance needed. A huge chamber will need more lead than a tiny chamber. also the shape of the chamber will change this Camshaft will play a small part. But in no way does the carb EFI dictate timing advance.