Replacing a good stock fuel pump with a different or later fuel pump is a waste of money. The fuel pressure regulator is supposed to control the pressure. In Jamey's case, apparently the existing pump couldn't maintain regulator pressure. Otherwise a different pump wouldn't have caused an increase in pressure. He needed a new pump, and in that case an '85 pump is a good idea. But don't replace the stock pump just because someone says the '85 will make more power. It won't make one ounce more power than the stock pump if the stock pump is doing it's job. A good way to test the fuel pump is to make a run that places the greatest possible demand on the pump while you observe the pressure. I taped a fuel pressure gauge to my windshield and made a 1/4 mile pass. Since I can't wind very high in third gear, in the 1/4, I paid especially close attention to the gauge as I was winding out second, before and at the shift into third gear. My stock fuel pump maintains the full 14 psi (my regulator setting) at 6200 rpms, at WOT, under the load of second gear. If your pump can maintain full pressure under the greatest demand you can place in it, a different pump will be a waste of money.

RACE ON!!!

 

You don't get it. Does my comment "I think his post count exceeds the number of words he has written." sound like I am referring to someone that "has a low post count"? You are posting blind, with no clue as to to what you are criticizing.



I son't usually make smart remarks just when I don't agree with a comment. Like my statement in the last paragraph, ""You are posting blind", isn't because I disagree with you, it is because, you in FACT haven't grasped the subject and your comment, therefore, is OFF subject.

And as for your criticism of my answering questions and countering criticisms of me, as you express, here, in twisted English:Haven't you, in this thread, done EXACTLY what you are yelling me for doing?

Give me your address and I'll ship you some capital letters.

RACE ON!!!

 

 

I forgot to mention that I doubt you will notice any difference in performance between 13.5 and 14 psi of fuel pressure.

RACE ON!!!

 

low post count or more post then words typed basically same thing. so what some guy enjoys reading more then typing and conversing. i still dont find that a crime and dont believe one should be bashed for it. i wasnt trying to say you are intentionally rude but some of your coments can be taken that way is all i was saying. yes i am basically doing the same i criticized about however i never said discusion was bad im just saying that bashing one person or his car his posts is useless and doesnt accomplish anything. it also seems to follow you from thread to thread and not necesarrily your fault mods close one thread for stuff and seems like whenever you post stock motor except for ported intake watch out a 3 page discusion starts as your other mods and what ya have and dont have and weather you properly disclosed them or not. basically i say who cares weather or not you tell everyone your complete mods as long as you answer the original posters ? apropriately. yes my typing and grammer are terrible ive never claimed it wasnt shoulda payed more attention in english class when i was younger instead of daydreaming about corvettes lol. i guess our best bet here is to agree to disagree on some things and call it quits with no hard feelings. i dont hold a grudge and have no intentions of qareling about this every time it happens just had to say something and said it is all.

 

Probably not, but when a car, especially one that may be considered a race car, is as slow as high 13's, anything is an improvement, right?

I would like to try this, but to be honest I am a little uncomfortable using tape to hold a fuel pressure gauge to my windshield. What kind of tape did you use, duct tape? I think track officials would prefer to see a fuel pressure gauge tapped into the fuel line, and mounted on the cowl in front of the windshield, but maybe the rules are different where you live?

 

The way cfi-efi says to do it is right.a hand held fuel pressure gauge is used by mechanics to diagnose fuel pump flow/delivery problems .it screws into the schrader valve on the fuel rail and has a hose attached to a round gauge.you want to put the engine under load to see it fuel pressure drops that's why you tape it to the windshield just so you can see it when you make a run.you don't keep it on for ever just for a run or two .btw you can tape it to the windshield at the track as long as its not going into the drivers compartment its ok.

 

This is incorrect for the 84 cfi, they have no fuel rails.


Jamey, you will need to locate a tee between the tb's. then just extend your gauge up to the winshield. Remember its only temporary. This is how mine is set up.

 

Thanks QWS. I already have a Snap On fuel pressure gauge set, which I used to check my fuel pressure under no load. I just found it hard to believe that you could tape something like that to a windshield while making a pass, but I stand corrected. I doubt my FP is fluctuating under load right now, so I am not worried about it.
Nice set up btw. Is that the DCS setup?

 

I'm not saying don't do it, but for a half pound, I doubt I would. You consider yours a race car? Mine is my DD. I have been known to drive it 850 miles, one way. to a race.



For a permanent installation, yes. But for a one run test of the fuel pump it is adequate. I ran the fuel hose for the gauge under a wiper blade. I'm not sire what I used for tape. I think it was a 2" wide clear cellophane tape. The CFI doesn't have fuel rails but you can attach the gauge wherever you do to check the pressure at idle. Where qws has those fancy blue anodized fittings, I have a brass running T. I have the flare fittings for the stock fuel lines at opposite ends and and a Schrader valve installed into the 1/8" NTP threads of the T.



Then there would be no need to waste money on a fuel pump.

RACE ON!!!

PS. I just took another look at the pic. My brass T is installed into the stock steel line between the TBs. No special braided hose. The T, flare tubing nuts, and Schrader valve all cost about $12.00, total.

 

Hey CFI,
What's your opinion on modifying the swirl plates?

 

Yes

 

Im not CFI but i'll give you some insite on this topic.This is a mixed opinion subject for the CFI people aswell. Some claim its a big restriction and hurts its performance but some claim it didn't do a thing to improve performance.

My car ran better with them in but modified slighly. Ran better by meaning it idled smoother and had better response than them out completely. I ran a 14.3@95mph with them out and I had 2" TB's at the same time with the ported intake. I swapped back to stock bored TB's and swirl plates and felt no difference in SOTP and Gtec showed no difference with muliple runs.

For a high 13-14 second car,the swirl plates aren't a problem and either is TB bore size. Similar debate goes with the 1996 LT4 cars and TB size. The underrated LT4's came with a 48mm TB just like a L98 did back in 1985. The LT4's didn't gain much if anything from a larger TB bore diameter and they made a 330chp from the factory. L83's made 205 and don't need more than the stock TB size to run high 13's. I know we are talking about a dry flow system and a wet flow system but the biggest restiction in the CF system lies in the intake runner size all together.

The 14psi fuel pressure everyone say to set it to is a myth to me. I run 12psi and my AFR is mid 11's across the rpm range. Any more fuel pressure and its waaaaaaaay to fat. I've tried 2 different WB02 set-ups and had the same results on both sides of the exhaust. Anything requiring 14psi or higher should have a fuel delivery problem or has a motor that is built to "handle" more fuel demand, i.e; cam,heads,headers,exhaust,etc.

 

I'm not "CFI" either, but I removed my swirl plates completely. I did it at the same time as other changes so I can't comment on perfromance difference, but I can say this; with them removed, and the bottom of the plenum lid radiused, it idled like stock and drove great w/no hesitations or hiccups. I agree that it's the runners that's the major restriction.

W'regard to fuel pressure, I also agree that adjusting it to arbitrary numbers is folly. You need to "feed your engine what it wants". Every engine is different, and only dyno time or track time (with consistent driving) will reveal what fuel pressure works best for YOUR combo.

MY car was running 15 PSI and a vacuum referenced FPR (~11 PSI at idle) when I sold it, and that's what worked for that engine, but that "data" is meaningless to you, since your combo is different.

-Tom

 

The debate seems to be more of an eliminate them or keep them question. I have no before and after data on these like I do some things. I feel for a DD like mine that the swirl plates are a plus. The bottom of the manifold isn't very far below the TBs, and fuel just loves to puddle, there. When I was putting my ported manifold back on, I trimmed the lip or cylinder that sticks below the bottom of the lid, flush and I even radiused the bore in the plate along with the bottom of the swirl plate cylinder. I then twisted the blades of the swirl plate to a less severe angle to reduce some of the restriction. It seems to work just fine, but I did no experimenting and have nothing to compare it to. At this point, if I were doing it again, I would do it the same way.

I would comment on SHINOBI-X's TB bore statement, but that would just spark another 2+ pages of accusations.

RACE ON!!!