http://store.summitracing.com/partdetail.asp?part=26508

How would I go about making that work with our TBI ECM and such. Will the wirering harness match up? Can I use the stock ECM? Why is it for trucks only? etc. anyone have any info on the system?

If I got the truck ECM wouldn't it work?

 

For $1000 you can build a lot better motor than just an intake system alone. If you are keeping your motor fairly mild there is no reason to stray from TBI. Multi port systems have their benifits and are better in the long run but on a mild TBI motor it is overkill. You would be better off swapping to TPI for half the cost of that kit.

 

Actualy it would be for a 450HP engine that a TPI cant feed for under 1000$ Plus Consering it includes the voretc intake manifold along with injectors that they will swap to 40LB's for 40$. If you think about it 40LB injectors = 400$ Vortec Intake manifold = ATLEAST 400$

Plus I wont have to loose the stock wirering harness or CPU from what edelbrock says.

Does anyone have experiance with it? Anyone know why its for trucks only?

 

You would be surprised with what i can do with a grand,

 

Complete waste of money IMO. There are far cheaper ways to make/get MPFI intakes. That still leaves one MAJOR weak link, which is the crappy stock ECM. Thats one of the main things thatll hold you back. Even with prom tuning I wouldnt be too crazy about using the stock ecm with MPFI. Youd be better off stepping up to a 7730, or possibly one of the later TBI pcms.

 

Once he has the hardward, he can repin to a 730 without a major problem, and burn his own proms from there...

As I'm slowly trying to put a TPI swap together, I'm finding after the serp brackets, and TPI itself (some guys on this board seriously think it's worth it's weight in gold ) - it can be more constantly than one might otherwise think.

Not saying the edelbrock kit is the best way, but it a 50 state legal option at least.

 

Well what I am trying to find out is if there is a easier option for us TBI guys to push some series power (450+) and still use the stock wirering harness along with computer making it alot easier. I contacted edelbrock and from what they say there chip that comes with the system is a lot easier to program and manage.

I do not see why you guys think its so exspensive. Remember this is a vortec system so the intak manifold the comes with this set up a lone can be very exspensive. The 40-or 45 Pound injectors can run you 400$. The chip system, fuel rails etc. All could run you way up there. With fuel prices at 3$ a gallon if it IMPROVES apon the TBIs gas milage that alone is gonna pay for itself in the long run if you want to push some series power.

In all seriousness I would like to see a TPI system that can push 450+ Horsepower and cost under 1000$ and be brand new... and improve your gas milage

So does anyone aggree with me yet?

If not anyone else have a solution for keeping the wirering harness, being a vortec set-up, being brand new, make over 450HP, and remain looking stock.

 

Its unlikely that youd really see much of an improvement, if any. Gas is gas and teh engine combo has more to do with the fuel economy then anything. The best way to get good fuel economy is to make sure its tuned well, or buy one of those 60 HP rolling roadblocks they sell now.

The cheapest way to do an MPFI fuel system up is to get a carb intake with bosses and build around that. That way you wont have to spend a zillion dollars. Everything else could probably be obtained used for less.

 

A tbi can also feed at least 400 HP when set up right. One of the best things you could do is to at least burn your own proms. Even better is to use a later ecm. Itll be more sophisticated and most likely will work better then the stock one. Also you can probably use your current harness. Just repin using the correct connectors. As always, the tune is critical for performance.

 

TBI will only feed up to 380HP as we found out because it wont supply enough fuel. And thats with a perfectly tuned engine running 90 pound injectors the biggest available. SO to solve this problem is what aimed me at this sytem. I could push this system to 575 HP NA on a engine thats not tuned 100%

 

High pressure fuel pump will go along way. You can pretty much raise it all you want if your running an external regulator. I would say up to 30 psi is definatly feasable with the stock regulator. the only requirement then is to balance the idle and WOT fuel requirements. 30 psi would bump the fuel flow up to around 140 some odd pph per injector if they are indeed 90 pph injectors. You can also use a VacAFPR. The 8746 seems to give the possibility of a minor patch to the prom to support some sort of correction. The tbi system already there I would assume so its worth a shot at least

 

See that does make prefect sense but see O am a little worried about puring that much gas through 2 50mm hole dead center of the engine. I am thinking just the air through there will be better then just use a MPFI system for gas source. Now here the real question. What would you call this system? lol

T.B.M.P.F.I. =Throttle Body Multi Port Fuel Injection

 

Wont be that much different then a carb. Teh fuel is still pouring in over the throttle blades. As a matter of fact, its a bit better as there will be good atomization with fuel injectors. Once its in the manifold the dynamics are the same. Basically its like having a 650-700 CFM carb with 2" bores.

 

The stock 454 TBI is around 700 cfm @ 1.5" hg pressure drop. I see lots of very powerful engines running around with 650-750 cfm carbs. The early high output chevy big blocks only used 780 cfm. Playing with DD2000 my engine specs made 490 FWHP @ 5,000 and 520 ft/lbs @ 3,500 with the specs for a stock 454 TBI. 1000 CFM only brings the power to 500 HP. It might restrict the engine more with a bigger cam, but the 383 isn't going to be turned very high. 6,000 will be about it. Keep in mind it is ported dart iron eagle 230 cc heads, CC-305 for a LT1, headers, 10.5:1 compression, etc. It will be a built engine. I have a feeling the BUILT 700r4 with 5 pinon planetaries doesn't stand a chance, over the long run.

Getting fuel won't be too hard. You can change the springs in the VAFPR and get just about any pressure. The stock late 454 throttle body ran 26-32 lbs of fuel pressure and 4.3 injectors. That was 240 HP worth of fuel from injectors that originally fed 140. See where I am going. My next engine is going to be a 450-500 fwhp 383 TBI engine(going to break 400 RWHP). The VAFPR (with a late 454 spring) on my current engine is letting me get 32 psi under load and 22 psi at idle. I am still using a 7747 though. I am thinking I will be changing to a chipped 8746 soon and using dimented's patch(reminds me).

I also have a pair of TBI injectors that came out of two I6 mexican trucks. Apparently some 250-292 I6s were equiped with a single barrel TBI. The iTBI remind me of the cross-fire ones except only one. I don't know much about them other than my engine had too much fuel to stay running, even when I used the previous 454 injector calibration. My guess would be around 110+lbs/hr. Sorry they don't have any #s on them. Engine looks very similar to this.

 

Oops, didn't attach. This is a TBI 250 but you get the idea.

 

Oh, and some Brazilian cars have the same TBI engine, but use alcohol instead. That means that there are even bigger injectors available for TBI.

 

Well your gonna need 140LB/HR (each injector) of gas if you want to push 450HP. If you can do that with the 90 Pounders please let me know. Or if you wanna sell some of those higher injectors ;-) LOL

 

Like I said before, crank up the pressure. The flowrate for the injectors scales by square root(new pressure/old pressure). This has been shown to hold true for common pressures used in tbi systems. Its perfectly acceptable to run higher pressures.

 

At 32 psi the 90 lb/hr 454 injector WILL feed 525+ HP. They do 320 with 12 psi 320HP *Sqrt(32/12)=525. Works the same way with power vs. pressure. With the VAFPR they will never see over 22 psi at idle.

I know it may be difficult, but if it were possible to get Brazilian Alcohol injectors I would. Maybe GM dealers can get them?

 

Sounds interesting. Is there a forumla out there to calculate what PSI does to the injectors?

 

Yes, new flowrate = old flowrate * square root(new pressure/old pressure). Should hold true for a reasonable range of pressures. I would guess it probably breaks down at higher pressures above 50 psi as velocity effects set in.

 

theres a guy on eba ythat sells bolt-on TBI's for our cars and they flow 750cfm, that's good enought for a 500hp motor. I'm buying one for the ZZ383 swap I'm doing this winter.

 

Well jimp the air isnt the issue TBI will flow plenty of air. Its always the gas and programing that TBI is a problem.

 

bigger injectors and burn a few chips

 

lol a few.....I'm on number 516 and counting. Of couse with what I know now I could tune it in a few weeks with an autoprom.

 

Well help us out lol.

 

The prom tunings going to be an issue no matter what your using, unless you go with a high $$$ aftermarket system. The only real issue with TBI is dynamic range. The injectors fire 2x as often so the PWs will be shorter. This would be an accute problem for a small block with a large cam. There would be a low demand at idle but a high demand at WOT, resulting in the need for a large dynamic range. On teh other hand, a 400 with good heads and a relatively mild cam wont suffer from this as much as there is a smaller dynamic range.

 

I think you can run at lower PW's but youd have to be mindful that what you see isnt quite what you get as the time for the injectors to open/close could become a signifiant part of the total time theyre commanded to fire, depending on what the PW is.