Can a pair of Crossfire TBI 400 be modified to supply 250 lbs/hr of fuel to an engine?

 

I'm assuming you mean total of both? The answer is yes. 30psi or slightly higher will give you 250 or more also assuming you are talking about 80/90lb injectors. I would highly suggest going to an external FPR to achieve those pressures.

 

250 lbs/hr would be somewhere beyond 500 horsepower.

Is 500+ horsepower realistic for a Crossfire system? I don't have any experience with them, but is seems high to me.

 

Thanks Buccaneer. I read what you did with your setup. Gave me a lot of hope. I'm rebuilding my 82 vette. Changing out to a Duntov 3:73 rear, TCI 6x6 auto trans with stand alone ecm, to be hooked to a Gen. I sbc 427 / 434 based on the Renegade crossfire design. Looking at the dyno sheets on the engine configurations I began to realize that with 90# injectors the engine flat-lined at 47 - 4800 rpm. (short range for an intake that starts it's power band at 2500.) Options were to downsize the cubic inches or figure out how to pump more fuel into the engine. And Schurkey is right, the engine flat lines right around 500 hp.

Did you do any other changes (mods) to your tbi 400's other than to swap out the original injectors with 90# 90 lbs/hr injectors? With external FPR, what did you do to eliminate the FPR in the rear tbi. Do you just back off on the screw for pressure?

 

32psi on my injectors that I know how much they flow at a given pressure will support 501hp and that's about 256pph. Mine are set at 24.5psi right now with a 255lph pump that is quieter than stock. 500HP N/A at the crank is a bit of a stretch with CFI I think, but I guess you could do it as long as you don't go static with the injectors. I run 80/85% on average DC on my injectors at WOT. It does peak higher only for a brief moment though. 460(ish)hp and below is very doable though. My TBs are bored to 2.13", they are not stock. Ben73's 84 vette TB's are 2.20" and he runs 12.20s right now as far as I know, but he may be faster now. We did a lot of flow bench testing on different TBs WAY back in the day and a 2.13" TB with a 3/8" spacer @28" H2O flows 773cfm. A 2.0" TB with a 3/8" spacer flows 720cfm. You MUST run an external FPR at the pressures mentioned or you WILL blow out the bladders and fuel WILL go everywhere and burn your car down. You have to run blank off plates on both TBs and remove both TB comp and reg side parts.Are you going to be running the EBL Flash II or something else?

I have been toying with the idea of building a 421in motor CFI, but only an idea right now. A 396 would be a nice choice though. What TC are you going to use, since you are going to be running a steep gear? Mine is 9.5" SS3200 YANK right now, but moving to a 3,600 soon.I love that converter and pulls like a wild man out of the bottom with DRs on. Mine drives like a stock TC right now on the street as well. CR on my motor is 10.7 also running 91 oct pump gas for street and 93/94 oct at the track when I pull the laptop out and start playing a bit. I hope this info helps a you out.

 

Thanks for the reply and info. Let me "chew on" what you posted. To be very straight forward with you, I've been working on have the Skip White group build the
engine, but, need to settle on a intake, fuel supply source first. A lot of your questions will depend upon the final intake/fuel source. I've had 427 & 434 carbed before in a chevelle and loved them both. It would nice to stick with the Renegade because everything fits neatly under the hood.

Have you ever thought about using a 2 barrel to 1 barl. low profile adapter bored out to the 2.25" to match the Renegade and using tbi 100's or 200's. ( or would that so disrupt the air flow as to actually lose power? ) Seems that with 4 injectors, the sum fuel supply would be solved. (creates other issues that would have to solved)

What dia. fuel supply and return lines did you have to use to handle your set up? Will 3/8" handle it? I keep finding some saying yes, some no, have to go to 1/2". Also, do you have increase the dia. coming out and back into the fuel tank. It would seem that the original would act as a restrictor reducing fuel flow.

Another, just a thought option, was to go to an Offenhauser flat top STR with 2x4 (or EFI's). Would still give the crossfire look and solve the fuel sum issue. Trying to keep it under the stock hood and streetable though.

 

Does Skip White sell anything that isn't bottom-feeder Chinese crap?

 

SWP, Nice! I'm sure they know what they are doing for sure and build killer motors. My motor was built/machined by a guy that races on the TV show Street Outlaws/No Prep Kings here in the local Phoenix area, he has a killer motor in his race car and can't wait to see what his new motor will do this season. Anyway... I don't feel that you will get the same performance going CFI vs. a carb or EFI big inch motor though. The draw back will be the size of the injectors needed to feed it properly on a big cube motor, I could be wrong though. I've never had the problem of feeding a large cube motor as a 427 with CFI before. However, running two, two barrel TBs bored out with four 80s I would think will do the trick, but nobody that I'm aware of has done that yet and sounds like yet another project. (grin) I do know that a single in-line 2.25" setup was done already though, but I don't remember how big of a cube motor it was going to feed, maybe a 406? I think in your plan, injector DC will become a limiting factor. If you could have custom 100# injectors base-lined @15psi made, then...Game On! There was a guy in NY that I was working with several years back that had an injector shop and we were working on doing just that, creating a larger injector, but ran into issues on making it reliable enough under WOT. If I could make that happen, the sky would be the limit at that point and the CFI world and big motors would go bug nuts.

I personally have already started a project for my motor going to an EFI setup while still using the Renegade as a manifold which will benefit the guys that don't want CFI anymore and still improve the drive-ability of a big motor car. As far as fuel lines go, on my 383 motor. I use custom TB fittings that my machinist made for me which still allows me to run 3/8 AN -6 fittings on everything vs. the sometimes problematic TB 45* flare nuts. The return line is 3/8 as well, but necked down the inside diameter coming out of TB to what a stock return line would be while still allowing me to run a 3/8 -6 at the output tube side. It works just fine for my motor, not so sure this would work for a 427 though, but maybe just going straight 3/8 would be better. I plan on offering these fittings on my site at some time soon just in-case anybody is interested.

My whole idea on what we have done was to make as many mods as possible to my motor to make it perform the way I wanted it to and still have everything fit under the stock hood and air cleaner for a neat stock looking package, both 82 and 84 corvette and any 3rd Gen. I think we have succeeded in that area, both in fitment and performance. I totally get your desire to have that "stock" look and that was my goal as well.

Here is a pic of what I did for the fittings... Enjoy!

 

I've taken a few days to digest all of the info that you posted. I love Street Outlaws (true racing - "run what you brung"). It is impressive the 'off line launch' of guys like Chief & Doc. We pray that the show keeps going and for all of their safety.

Thanks for picture of your engine. CLEAN! no clutter. It is interesting how you did the fuel fittings and fuel line bends. I'll save the pict for future reference. Thanks.

It appears that it is not going to be possible to do a 427 with TBI 400's. I've spent a lot of time looking at the Offenhauser low profile ram as an option and have been reading the blog posts. You really get around. It also appears that you were in on the original design ( or redesign ) of the Renegade. Appears that you are one of the true experts on the Renegade. Thanks for all your posts helping people! I've been reading a lot of your posts from June, etc..

It appears the Offy power band is around 3 - 7 K. ( a little high for the street ). While the Renegade is 22 / 2500 -6 K. What do you think would happen to the flow characteristics of the Renegade if it were cut/ bored out to accept 2 Holley 4 barls. like the Offy. I also noticed that the Offy raised the carbs about a 1/2" - to impove flow? Do you think this is a viable option?

 

WOW! That would be cool as hell huh? Not sure what size you would want to go to and would have to do the math, but I would think no more than 600cfm would be ok. Do the math on motor VE and see what it comes out to. The real issue would be keeping it all under a stock hood which I don't think you will be able to do, but I could be wrong. If you put a mail box on the hood, anything is possible. A 1/2" spacer sounds about right, maybe more? BTW, my motor machinist old motor was 800 cu in, his new motor for the season is MUCH larger. I think the No Prep Kings people are in for a shock this season. I've seen the motor and have pics...It's a BEAST! He rented the track at WildHorse Pass to do some passes to check some suspension mods he made and he invited me out. Just his crew, me and two of my friends. WOW! That car is a beast of a car, even got a vid.