View unanswered posts | View active topics It is currently Sat Aug 19, 2017 7:05 am



Reply to topic  [ 18 posts ]  Go to page 1, 2  Next
 Newbie with lots of questions 
Author Message

Joined: Mon Jun 16, 2014 9:28 am
Posts: 11
Hello from Australia!! I was messaging back and forth with jmarkaudio on another forum a few months ago and he suggested I join this forum. With busy work and family I have finally got around to it so here goes.

I have a rover 4.6 in an MGB. It is not a race engine but a high spec road engine. With a Edelbrock performer dual plane and Holley Ultra HP 650 DP makes 235 rwHP. I am not overly happy with the carb set up (done by a local tuner) but thats is another story. Anyway I have been seriously thinking about a single plane manifold - not a mainstream brand - but a good reputation and from all reports i confidently expect 260 - 265 rwHP. Also reports say its suffers from typical single plane lower rpm torque deficit.

My real question is with the right carb choice, the right boosters, and careful tuning can the low rpm torque deficit be reduced or even eliminated? I am thinking to get mine 650 modified or start from the beginning again. If i start again my thoughts are to start from a 600 CFM base and have annular boosters installed get tuneable metering blocks etc. I am installing O2 sensors as a key tuning tool. As you can no doubt tell I am a novice but am very keen to work hard on an optimal solution.

Any suggestion, guidance and feedback would be greatly appreciated. Cheers Graeme


Tue Jun 17, 2014 7:56 am
Profile
Site Admin

Joined: Fri Feb 08, 2013 2:37 pm
Posts: 1744
Salutations to the Land of Vegemite.

Do you have more than one carb to work with? What is in your stash or available to you? How are you fixed for QJets?

The 650 HP is a good carb after some adjustments to the air bleeds and normal tuning procedures.


Tue Jun 17, 2014 6:02 pm
Profile

Joined: Mon Jun 16, 2014 9:28 am
Posts: 11
Thanks Tuner, I have an Edelbrock performer series 500CFM. I have read that this carb is less performance orientated then the 4150 based carbs. Is that a fair assumption. I have also thought of the Q-jet. Cheers, Graeme.


Tue Jun 17, 2014 7:52 pm
Profile

Joined: Mon Jun 16, 2014 9:28 am
Posts: 11
I may also have access to an older Holley 600 spreadbore. Cheers, Graeme.


Tue Jun 17, 2014 8:00 pm
Profile

Joined: Mon Jun 16, 2014 9:28 am
Posts: 11
Any feedback........anyone B| . Bueller.............Bueller..........

OK let me take another tact. What do I have to do make my Holley 650 Street HP to work on my Rover 4.6?? From how it has run so far it is OK at WOT and in a race track environment but the size of the carb combined with straight leg boosters just doesn't work on the street.

Annular boosters? New base plate with smaller dia throttle blades? Different or customer metering blocks? At least as a general base line then tune from there.

I did not do the original tune so am not sure of the internal specific but will put is apart this week and everyone know. What other information do you need? Cheers Graeme


Sun Jun 22, 2014 8:17 am
Profile
Site Admin
User avatar

Joined: Fri Feb 08, 2013 5:50 pm
Posts: 2359
I might consider putting annular boosters in the biggest DP you have, 650 if that is it, that should improve overall power with the single plane. It will take a little tuning but worth it in the end. For metering block mods check out the link, it shows how to make the idle feeds adjustable, and if it's in the upper location you will relocated it the lower. If that 650 has them in the idle well you will need to pull the plugs on top, the outer ones, and remove the old restrictions. This will allow proper tuning of the idle circuit for your engine.


Sun Jun 22, 2014 9:35 am
Profile

Joined: Mon Jun 16, 2014 9:28 am
Posts: 11
Thanks Mark, You mention a link but I can't see one in your post. Also regardless of what I already have what, in your opinion, would be the best carb base to work from? If needs be I may as well sell the carbs I have and start with the best carb from the base to get the fundamentals right and work from there. Thanks again and cheers, Graeme


Sun Jun 22, 2014 9:46 am
Profile
Site Admin
User avatar

Joined: Fri Feb 08, 2013 5:50 pm
Posts: 2359
Sorry, forgot that.

viewtopic.php?f=25&t=18


Sun Jun 22, 2014 10:27 am
Profile
Site Admin
User avatar

Joined: Fri Feb 08, 2013 5:50 pm
Posts: 2359
The Quick Fuel SS-650-AN is a possibility, it's a street able carb with a choke but has annular boosters.


Sun Jun 22, 2014 10:35 am
Profile

Joined: Mon Jun 16, 2014 9:28 am
Posts: 11
I have seen that BLP do a 600 CFM "Weekend Warrior". Maybe they could install their annular boosters in this as well to improve responsiveness and effective reduce the CFM to 525 - 550 CFM.

My concern is (happy to admit this maybe unfounded) that 650 CFM could be too large to start off with considering the engine is only 283 cubic inch.

Thanks again and kind regards, Graeme


Sun Jun 22, 2014 7:34 pm
Profile
Display posts from previous:  Sort by  
Reply to topic   [ 18 posts ]  Go to page 1, 2  Next

Who is online

Users browsing this forum: No registered users and 0 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group
Designed by ST Software for PTF.