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HybridZ

4 BBL intake manifold


gretchen/jason

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Well ive been reding about how to get more power out of a non turbo L6 engine . I have a 78 280z with a F54 block flat top pistons and a 77 280z head for high compresion . I did 4.11 gears lightend the car added Nitrous etc etc .

I added headers ignition products it all did nothing or close to it . Now you can add bigger injectors , a stand alone fuel system etc etc but unless a custom intake manifold is built it is all a waste of money .

 

I spent 700$ to convert to a 4 bbl carb and it is awseome , i meen the power it added is great and runs so smooth , a upgrade on my fuel injection was going to run me about 3,000$ intake and all i said to heck with it and added a carb seeing as id get the same powe results .

 

I got pics if anyone wants to see just e mail me at send e mails to jason my e mail address is so just e mail my persona e mail address .. gretchenlee1480@msn.com

 

And for anyone who wants to know it is a Arizona z car intake manifold and i do use a nitrous plate , but then getting a air cleaner for it is a hard thing to do as the hood clearance is about 1/2 inch ..

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Great results are always very satisfying....Goo job!!

 

 

I will say that I have been through a number of "upgraded" fuel system components....some are not as good as they seem at first.

 

I grant that the original intake may not have been flowing enough air for 6000+RPM torque numbers....but the fuel system should have been able to keep up with most of the powerband.

 

Many times people "upgrade" to a new fuel system when the original system is broken and malfunctioning. Under those circumstances the improvement seems huge...but usually it is not that great.

 

Keep in mind that many folks have to consider the Inspection Nazis once a year. Original equipment has great value to these people.

 

About the 4BBL conversion.... It seems capable of flowing more than enough air and mixing in great quantities of fuel. But it can have some drawbacks....

 

1. poor fuel distribution between cylinders....can cause premature wear of the rings on some cylinders...lean detonation on others. Not that Nissan did this right either....

2. gasoline can pool below the carby and "run" into the engine on hard corners...Auto crossing on a hot day can make this a nightmare.

3. you wont pass inspection in most cities

4. I dont like the feel of the primary/secondary downdraft carbys with these motors.

That is subjective...but a good set of S.U.s with tight shafts have a WONDERFUL linear "feel"....very predictable when feathering the throttle in sweepers...or getting power on quickly and smoothly comming out of a turn.

 

I have a set of dual Weber DGV carbys, twin Cannon manifolds, with the jet kits, 2 rebuild kits, and a spare carby brand new in the box. I ran this set up because my SUs were worn out and this seemed like an improvement. This is all sitting on a shelf now.

 

3 years later I got a fresh set of 4 screw SUs and removed the stupid Weber downdrafts. I spent at least $1500.00 and COUNTLESS man hours trying to make those carbys do what the SUs just do naturally and better.

 

Good luck with the 4BBL conversion...I am interested in how they hold up for you in the long term.

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  • 2 weeks later...
I have a set of dual Weber DGV carbys, twin Cannon manifolds, with the jet kits, 2 rebuild kits, and a spare carby brand new in the box. I ran this set up because my SUs were worn out and this seemed like an improvement. This is all sitting on a shelf now.

 

Roger that. I got the Webers for the exact same reason and because they were smog legal. The kit was the same price as properly rebuilt SU's. If I had it to do over again I would definitely get the SU's.

 

I have heard bad things about the 4 bbl set up on a Z. Will be interesting to see how things work out for you. But I can't argue with the price aspect.

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Well people say bad things about stuff they cant fix or have never tried . So far this carb has been the greatest thing ive done to my z . Now gas mileage sux i get around 12-13 miles per gallon .

But im out for power not gas mileage , emissions wise my car passes just as good as the EFI system i had but ive gained more power for less $ , i dynoed it a week ago and ive gained 13 rear wheel horses and 15 in torque . Not bad for 800$ .

Now ive heard good things about the SU,s but i want my z to look different so i went the 4 bbl route and im impressed by it .

 

jason

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  • 4 weeks later...

I use the stock fuel injection fuel pump . I ave a aeromotive fuel regulator with a fuel return line that cost me around 160$ . it works great adjust the pressure from 3-9 psi . Id recomend this regulator if you have a fuel injection fuel pump .

 

Soon to stroke the L28 and polish and port the head and balance the crank etc etc .

 

Jason

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Put it on a dyno and let's see what kind of difference it made!

 

I put a Megasquirt on a similar engine (F54/N47, header, 60mmTB, stock head and cam), and I measured 165hp/175ft-lbs at the wheels. The Megasquirt converison cost me less than $200 and it is fully programable. I get 22mpg on the race track with it!

 

 

Pete

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