This may or may not fly but thought it would be interesting to do a thread on modding the CFI and a TPI car. There are to many threads on here where you hear the same old story. CFI has its limits with hp and "whats out there" as far as bolt ons are limited, and the TPI is an unlimited amount of bolts ons. Anyways let try and not go there... and instead pose this question to you guys....

You have 3 cars (84,85,&87 all bone stock), your goal is 325 hp at the flywheel with good torque. What is the cheapest and easiest mods to get these cars there? and still economical. No juice or supercharger either...

Like I said you guys may or may not like this but way to often many users have only goals of this and not 4 or 500 hp and when shopping for a C4 want to get a good reliable car that they can mod to a point where the car is no longer useable as a dd.

 

I dunno about the crossfire, but the TPI car should be pretty easy to get there. My car makes 275 RWHP (which is pretty close to your goal of 325 CHP, depending on what BS theory you use to calculate engine HP) with long tube headers, cat back, 1.6 roller rockers, K&N with cut lid, !AIR pump, air foil (!), and a custom dyno tune.

With that set up, on sticky tires, I run high 12's at 106 at the drag strip.

I've still got some small bolt on things left that would push my numbers higher, but I haven't gotten around to them yet. An electric water pump, under drive pulleys, etc...

 

i dont understand why people think TPI has "unlimited" boltons offered by the aftermarket while the Xfire has little to none?

- both have K&N filters
- the exhaust parts are the same for both cars
- any type of stall converter or clutch will work on either
- aftermarket gear options are the same
- cylinder heads, cam, and valvetrain upgrades work for both
- crank pullies, rocker arms, AIR delete stuff are the same

the only difference i can see would be the few aftermarket base manifolds/runners that are availible for the TPI cars. But then the Xfire has the Xram intake as well. This is excluding of course, airfoils, AFPRs, and TB bypass kits for the TPI cars, but most TPI guys can agree that these things dont do much if anything at all

so can someone enlighten me?

 

Both systems suck. Check out the last cfi vs tpi thread where the CFI 'experts' actually admit to turning the distributor to adjust spark advance on an ELECTRONIC FUEL INJECTION SYSTEM. Funny stuff.

How about ditch both and go with a real multiport system? A converted LT1 intake?

-- Joe

 

They will both cost you a bundle.

 

really? i've got headers, true dual exhaust, 1.5 rockers, heads, and removed the air pump. I know I can easily keep up with my friend's LS1 firebird but I didnt think it would have 275 at the wheels. Now you got me thinking about new rockers and a tune

 

Why three cars? You get away from an equal starting point with the '88 with it's aluminum heads and roller cam. Except for the camshafts the 1984 and the 1985 long blocks are identical.

RACE ON!!!

 

Have anyone on this board tried put aftermarket heads and exhaust on a Xfire motor? And if so, what was the performance outcome?
Randy

 

Isn't that how it works? You set the base timing with the distributor mechanically, and the ECM adjusts it from there. Though really, electronic fueling doesn't necessarily imply electronic spark control. What am I missing?

 

The tune was the biggest thing. I picked up 30 RWHP and 51 RWTQ from the tune. I did it myself on a dyno. All in all, I made 41 pulls on the dyno tweaking things here and there. I went from a best of 13.6 @ 101 to 12.84 @ 106.07 after the tune; some of that gain is the driver mod, but the MPH gain is all from the tune.

 

Thats a valid question,and glad you asked. The 84 and 85 differance is only the intake,camshafts
Didn't choose the 86 since two types of heads were used so I went with the 87.

I didn't choose the 88. And your right I did get away from an equal starting point

84-205hp/290 tq
85-230hp/330 tq
87-240hp/345 tq


So what I want to know is how each car could reach the goal of 325hp, thats the cheapest and easiest mods,and still keep it an economical driver.

 

Joe is busting my ***** b/c I timed an engine (or several) by doing what you said. He thinks this is a joke of a way of doing it. In his opinion, the ONLY way to do it, is to put the car on a dyno, and recurve the ignition to tailor it to the engine combo, achieving max tq at every RPM increment.

While Joe's way is the BEST way, it's not the ONLY way, as I achieved the criteria I had set (over 300 hp and aver 20mpg [over 24 actually]). So Joe doesn't know it, but there is more than one way to skin a cat.

Joe also thinks:
...that God's answers to all SBC's is the LT1 intake. Or some variation thereof. Unfortunately for Joe, he is too close minded to realize that some people don't set the same criteria that he does, for their cars, and that not all SBC's need LT1 intakes. I wonder if Joe thinks that I should put an LT1 intake on my LS2. Perhaps I should berate Joe for peddling his "ancient", tractor-like LTx, cast iron "technology". Of course I wouldn't though, because unlike Joe, I like and respect older, even out dated engines and systems. Even the out dated LTx systems.

Back on topic; I think you all know what I think: CFI the cheapest and easiest mod is porting and you need to port, way, WAY more than most people do. Then, it's the same as any other SBC, except, unlike TPI, It's not hampered by the looooong tube runners. So ported intake, and modded lid, injectors, cam in the 220-230 duration range headers and decent exhaust, and ported heads, would be the cheapest way, IMO.

 

Buy a LT1 car, drop in a hotcam kit and a tune and you are done. Why start at the bottom?

 

Speaking of "suck"!


How else do you change the timing? That IS the way to set the timing. What is funny is your emphasis on, indicated by capital letters, "an ELECTRONIC FUEL INJECTION SYSTEM". Twisting the distributor in "an ELECTRONIC FUEL INJECTION SYSTEM" has exactly the same consequences as doing so with a carbureted engine. Besides indiscriminately cranking in the advance, subscribes to your simplistic theory of:And if that isn't enough "Funny stuff", here is a real knee slapper.

In reference to removing the ECM in a carb conversion, comes THIS gem:
When confronted with wild rantings, it pays to apply a little common sense to weigh the merits of the claims. It doesn't hurt to consider the source, either.

Next we can discuss Boyle's Ideal Gasoline Laws.

RACE ON!!!

 

Which of the three cars is "the bottom"? Two are not that different from yours. Certainly, I can think of many Corvettes that are more "bottomer" than even the CFI 'Vette.

Compared to my current car, YOU'RE driving a car that's "at the bottom". You're kind of like Joe, that way. Ever heard of a glass house?

 

You are thick as a brick. This is a game it's not real. I simply changed the rules. I know exactly what I have and why I bought it. If I had wanted a 325 HP+ car I would have started with a LT1.

 

VACATION TIME! Not to mention something about pots and black kettles.

 

 

You sure it's closed?????

 

I'm back from vacation!!!