38/38 Carbs

[Albert]

Hey,

anyone here installed 38/38 Dual Webbers before? I have a set I am installing now into my 3.0cs wanted to see if anyone had any tips or pics of their setup. This will have to do till I have time for a motor swap. Help is always greatly appreciated thank you!

 

[HB Chris]

It’s a common mod, your air cleaner will sit closer to firewall and may interfere with hood light.

 

[lip277]

I did that installation on my 2002 I had.
Had the engine rebuilt with 9.5 to 1 pistons with 32/36 DGAV Weber (CA smog compliant as I was in CA then).
Ran ok - then... 10 years later...
I installed a tii distributor, Pertronix and (as the 32/36 was getting tired) a 38/38 DGAS.
HUGE difference.... wish I had done that years back.

If you have a 3.5L M30, I would imagine it would also be an improvement. It pumps a fair bit more gas than the 32/36 - but if your engine can take it - would be an interesting mod.

 

[Mike Goble]

I have dual Chinese knock-off 38/38's on my M30B35 and they work very well. The throttle response compared to the 32/36's previously installed is quite a bit better due to the fact that you are opening all four bores simultaneously I use the stock jetting with one size larger idle jets.

 

[Adkfrank]

Not sure if this helps

 

[Ohmess]

I was talking with Carl Nelson in CA a couple of years ago about my triple Weber setup; he told me he prefers the 38/38 Webers. If this is Carl's preferred setup, there have got to be a bunch of those out there.

 

[jmackro]

Not sure if this helps

What's that second set of cables going to the carbs? I'd guess they were manual chokes, but see the electrical choke actuators on the far sides (in the photo) of your 38/38's.

 

[dang]

your air cleaner will sit closer to firewall

Huh. I never realized it was because of my 38/38's and I put them on! The latch closest to the firewall is difficult to use because of the clearance. As far as the carbs go, they work fine but I think my stock 2.8L can't take advantage of them. They seem to just make more noise but the car doesn't go any faster. Jets maybe.

 

[Adkfrank]

What's that second set of cables going to the carbs? I'd guess they were manual chokes, but see the electrical choke actuators on the far sides (in the photo) of your 38/38's.

There are only two cables one to each carb from the linkage.

 

[jmackro]

As far as the carbs go, they work fine but I think my stock 2.8L can't take advantage of them. They seem to just make more noise but the car doesn't go any faster. Jets maybe.

Bigger carbs don't make an engine put out more power unless they replace carbs that were undersized. An engine can only draw so much fuel/air mixture, based on its displacement, cams, and porting. If your carbs can deliver the maximum amount of fuel/air required, bigger carbs or different jetting won't make any difference - in fact, too-big carbs may reduce performance at the low-end.

 

[dang]

Bigger carbs don't make an engine put out more power unless they replace carbs that were undersized. An engine can only draw so much fuel/air mixture, based on its displacement, cams, and porting. If your carbs can deliver the maximum amount of fuel/air required, bigger carbs or different jetting won't make any difference - in fact, too-big carbs may reduce performance at the low-end.

Yup, it's definitely over carbureted. I still have my Zeniths but those are going on my E3 now since the carbs on that car have been sitting for 25 years.

 

[Stan]

I have the Weber 38/38 on my M30b35 with 10.5 : 1 and a Paul Burke cam, 1-2-3 ignition, headers and lightened flywheel. Very happy with performance

 

[jmackro]

There are only two cables one to each carb from the linkage.

Well, it's your car and I guess you would know. But in the photo below, I'm seeing four, black-sheathed cables: Two come up from below and connect to the accelerator linkage. And then two more seem to come in horizontally, one to each carb, have a red inner cable and connect to an aluminum ferule. I'd guess that this second pair is for the choke, but your 38/38's seem to have electric chokes.

 

[Adkfrank]

Well, it's your car and I guess you would know. But in the photo below, I'm seeing four, black-sheathed cables: Two come up from below and connect to the accelerator linkage. And then two more seem to come in horizontally, one to each carb, have a red inner cable and connect to an aluminum ferule. I'd guess that this second pair is for the choke, but your 38/38's seem to have electric chokes.

In this pic it may be easier to see the route of the cable.

 

[jmackro]

In this pic it may be easier to see the route of the cable.

Ah, got it. Instead of four cables, I'm seeing both ends of two cables.

Thanks!

 

[tmh]

I have dual Chinese knock-off 38/38's on my M30B35 and they work very well. The throttle response compared to the 32/36's previously installed is quite a bit better due to the fact that you are opening all four bores simultaneously I use the stock jetting with one size larger idle jets.

Can you tell me the jet sizes for your 38/38's as to mains, idle, emulsion tubes, and air correction? I am happy to hear what others are using as well.
T.M.

 

[Mike Goble]

Here's a listing of the current stock jetting. I used 50 idle jets to get the off-idle response up to par.

Top End Performance - Baseline Jetting that comes in current new Weber carb models.

Top End Performance has been your source for the best prices on brand name, top quality car parts since 1994. Our commitment to providing the best parts at the best prices is topped only by our dedication to providing the very best service to our clients. We are here to help - that's the Top End...

www.racetep.com

 

[shanon]

I am in process from going dual 38s to triple 45s.

Reason: with a 300deg Alpina cam and oversized valves, I alwaya thought this motor had 'more' when we raced it with triple 40s. It pulled harder and achieved a higher rpm..

But the triple 40s went a different direction when my brother and I did some horse trading years ago. So I put dual Webers on it to get up and running. First 32/36s cuz that's what I had, then to the 38s. Motor did better, but i always wanted some triples since my first car, Dad's TR6...plus the memories of racing the motor. So 2 carbs have become 3.

Whether they were ever at their optimum setup, only a full dyno tune would tell. But I decided to realize the triple dream before that ever happened.

I certainaly liked the 38s over the 32/36s. Punchier, felt they pulled better.

So...happy to share info on them, jets, etc. There on the bench at the batcave.. If your looking for a set of 38s (with velocity horns), let me know. I'm not sure of their fate currently and I'm trying to be minimal on the parts stash.

 

[Mot27cars]

I am in process from going dual 38s to triple 45s.

Reason: with a 300deg Alpina cam and oversized valves, I alwaya thought this motor had 'more' when we raced it with triple 40s. It pulled harder and achieved a higher rpm..

But the triple 40s went a different direction when my brother and I did some horse trading years ago. So I put dual Webers on it to get up and running. First 32/36s cuz that's what I had, then to the 38s. Motor did better, but i always wanted some triples since my first car, Dad's TR6...plus the memories of racing the motor. So 2 carbs have become 3.

Whether they were ever at their optimum setup, only a full dyno tune would tell. But I decided to realize the triple dream before that ever happened.

I certainaly liked the 38s over the 32/36s. Punchier, felt they pulled better.

So...happy to share info on them, jets, etc. There on the bench at the batcave.. If your looking for a set of 38s (with velocity horns), let me know. I'm not sure of their fate currently and trying I'm trying to be minimal on the parts stash.

Hi. Sent a message to you.
Tom

 

[TedS]

Anyone running dual 38's (as opposed to 32/36's) notice the return springs are too stiff?