[bret brummitt]

I'm just getting into the FI conversion on my GT and I've got the setup except for the fuel pump and the throttle setup.

Anyone want to steer me in the right direction ?

 

[opelgt73]

I have an electric fuel pump that was used when my new GT was converted to dual sidedrafts, would that work for the FI?

 

[Travis]

Fuel injection requires a MUCH higher pressure pump (~40+psi)

-Travis

 

[davegt27]

which FI setup do you have

1.9 or 2.0 the throttle set up is a little different for each


as for the fuel pump there are a few ways to go about this also

one is to cut the tank open and add a surge tank and fuel pump and return line

the other is to mount the stock pump some where on the car
and run a return line

Davegt74

 

[bret brummitt]

I actually have both the 2.0 and 1.9 setups, and I think I'll be doing both at the same time.

I'm planning on mounting the pump externally at the rear and runing return lines as I've got 2 '73 tanks to use.
Will most any external FI pumps work, or is it best to stick with a Bosch unit rather than try to raid the plentitude of the Japanese?
-Bret

 

[opelbits]

Whichever you choose, if you are not buying a brand new one, make sure it is VERY common and easy to find. A good deal on a used pump isn't such a good deal if yours goes out if they are hard to find and cost a fortune.

 

[davegt27]

The 2.0 FI is kind of easy to setup since OGTS sell the stuff for it

but once you see it you will say i could of did this


the 1.9 is a pain (it has such a large range of motion) unless you have the 75 valve cover

if you don't have the 75 valve cover you will need a bracket at about the same location (the passenger side of the valve cover)

its hard to describe

sounds like your right on with the fuel pump i mounted mine at the rear of the car

The stock 75 fuel pump was right near the left rear tire
(i know not the best setup but it worked)

i used the 75 pump and the stock 75 FI pump bracket (I'm cheap)

you could use whatever FI pump you like just make sure you check the pressure, once you have verified the pressure is good under different driving conditions then you can take the high pressure gage off

i had a gage tie warped outside the windshield for awhile


for those wondering i hardly noticed any difference between the 1.9 and the 2.0 FI setup (TB's are the same size)


HTH
Davegt74

 

[bret brummitt]

Sounds good.
Looks like I'll get to find out the characteristics of both first hand.
I plan on starting in on it all next weekend.
Can't wait to make the transition.

 

[RallyBob]

Dave is right, the TB's of the 1.9 and 2.0 FI are the same size. But the 2.0 has a much larger air flow meter. So it has more potential for a modified engine. A stock engine can't take advantage of the increased airflow potential anyway, so as Dave said, it will be a negligable improvement between the two.

Bob

 

[bret brummitt]

I'm running a 2.0l( chevy 265 setup in both lower and heads).
Should I concetrate on modifying the 2.0l setup before slapping it on.

 

[RallyBob]

I'd definitely run the 2.0 injection then. The larger air flap has more mass, and is less sensitive to the pulses you'd get if you changed out the cam to a hotter one. It will make better top-end power too. If you decide to install a hotter cam, make sure you specify that the cam is ground with a wider lobe separation angle. At least 110 degrees, preferably closer to 112 degrees. Running a cam with narrower lobe separation, such as 108 degrees, might give better torque and power in a carb'd engine, but it will wreak havoc on the FI system's ability to read the airflow. Go for the wider lobe separation to smooth the idle....the longer intake runners and plenum of the FI will take care of the torque. Also, limit maximum duration @ .050" to no more than 220-225 degrees....MAX! I'd even prefer to see a bit less, maybe 214-218 degrees. This will wake the FI up.

 

[Paul]

More About Cams

Bob,

I love it when you talk CAMs to us. LOL.....

We might even need a new thread for this. A while back you gave advice, to someone needing modest performance increases, for cam lobe profiles from Cameffects I think. I haven't located it just yet, but I think you gave a profile number and a lift for each of the Exhaust and Intake. ?# profile, .408 lift Intake(Right?) & ?#profile, .394 lift Exhaust (right?). You suggested the split profile to help Improve the balance in intake vs exhaust flow, I presume. How did that profile meet your above suggestion for a shorter duration? Lots of the information I've read lately discusses the importance of proper Intake valve closing angle. Do you happen to remember the angles of that profile? If someone has upped to the 42mm (2.0) Intake valve to improve flow balance, how would this affect their choice of cam lobes and lifts? Lets assume stock springs, so that limits cam lifts automatically. Lets keep the discussion to Hydraulic lifter cams and for the sake of following the above thread, and lets first consider FI first before the conversation moves on to carbs.

Again... Our many thanks

Paul Crane

 

[opelgt73]

Bob,
Speaking of FI,
I know that you said you would be installing a supercharger on your 2.4L motor and that you would be using a carb for that, now say I wanted to use a turbo charger, would it be more advantageous to use the FI setup or a carb for forced induction?
the motor would be a 2.0L flat top piston, with big valve kit, and a stock cam(I am under the impression that you cant go wild with cam profiles with a turbo)


Thanks,
Chris

 

[RallyBob]

For a turbo, I'd only go with FI, and only aftermarket ECU at that. The factory Opel stuff really can't handle boost all too well. In the case of my supercharger, it's designed to be a draw-through system without an intercooler, so a carburetor is a natural choice. But with a turbo, the best way is to go with FI and an intercooler.

As far as cams, it's best to go with milder profiles, but if the head flows well, it will respond to cam changes just the same. Again, keep the duration moderate and the lobe separation angle wide. Go for all the lift the engine will handle, the turbo will love it.

Ironically though, you CAN cam a turbo engine pretty well. But with a lot of overlap, the boost bleeds right out the tailpipe. Now, if you INCREASE the turbo boost to compensate for this loss of pressure, the power will increase even more. The down side to this is you now have to deal with turbo lag AND waiting for the engine to 'come on' the cam. So it will have a lot of power but will hit VERY abruptly. A milder cam is a better solution to this, the engine will be more flexible and torquey.

Turbos tend to favor more intake lift/duration, as opposed to superchargers and nitrous applications which need more exhaust lift/duration. The reasoning for this is the turbocharger scavenges the exhaust quite well, and now you need to allow all that pressurized air back into the intake side.

 

[RallyBob]

Re: More About Cams

Bob,

I love it when you talk CAMs to us. LOL.....

We might even need a new thread for this. A while back you gave advice, to someone needing modest performance increases, for cam lobe profiles from Cameffects I think. I haven't located it just yet, but I think you gave a profile number and a lift for each of the Exhaust and Intake. ?# profile, .408 lift Intake(Right?) & ?#profile, .394 lift Exhaust (right?). You suggested the split profile to help Improve the balance in intake vs exhaust flow, I presume. How did that profile meet your above suggestion for a shorter duration? Lots of the information I've read lately discusses the importance of proper Intake valve closing angle. Do you happen to remember the angles of that profile? If someone has upped to the 42mm (2.0) Intake valve to improve flow balance, how would this affect their choice of cam lobes and lifts? Lets assume stock springs, so that limits cam lifts automatically. Lets keep the discussion to Hydraulic lifter cams and for the sake of following the above thread, and lets first consider FI first before the conversation moves on to carbs.

Again... Our many thanks

Paul Crane

I think it sounds like you're refering to the F270/F265 cam profile from Cam Techniques, not Cam Effects. It has .270" intake lobe lift, and .265" exhaust lobe lift (x 1.5 rocker ratio= .405" intake and .398" exhaust lift). This cam has 220 degrees intake duration @ .050" and 214 degrees exhaust duration @ .050". I normally use it with 109 degrees of lobe separation for carb'd engines. I'd go with 111 or 112 for fuel injection. A 2.4 could even use 114 degree lobe separation. That cam is a solid profile ('F' for flat-tappet), but the ramps are gentle enough it can be used for hydraulics (have done it for years with no issues).

Regarding the intake valves and FI situation. Yes, they are all relevant. This is why cams are SOOO important, and virtually every cam must be chosen for EACH SPECIFIC ENGINE!! I would recommend a different cam most likely. It also depends on the exhaust choice and how well the head flows (not just valve sizes). I used to use my flowbench more for determining cam choices than for improving airflow, it's that critical!

 

[Paul]

Cam for 75 FI Manta

Yea, those were the cam specs I was refering to. So, Bob, you would really wouldn't recommend that cam for a mildly tuned FI 1.9?

Okay, if you don't mind, what would be the MOST cam you'd recommend for the following:
1.9 liter .030 over bore; flat top pistons; Gapless #2 piston rings; .050 milled from the head; Hydraulic lifters; 42mm intake valves w/ intake guide protrusions reduced by 1/4" and rounded over, area behind valve enlarged to diameter equal to 75% area of valve, all sharpe edges removed and contours fully radiused, exhaust valves... new stock valves and hardened seats... all sharp edges removed, obviously new guides; crappy header (trying to re-work) w/2" exhaust...; stock 75 FI; Pertronix trigger and Crane PS-91 coil. Future modifications under serious consideration: 2.0 pistons & Roller Rockers.

I'd like the most cam that you would personally want for the above engine with the stock valve springs. I'd even consider a cam requiring new springs.

As long as the FI operates smoothly, I can live with any resultant power band shift.

Again, Thanks
Paul