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Duratec GSXR throttle bodies, injectors and fuel return

gav2612 - 19/12/15 at 10:36 AM

Guys, in the middle of a very steep learning curve and could do with some advice/input. My head is spinning from google searches!

I'm swapping an old crossflow 1700 for a 2.0 St150 fiesta duratec into a 1993 Sylva Striker and mating it up with a mk3 Mx5 gearbox. All going fairly well mechanically so far. ive got as far as test fitting the enigne and box and will soon be making up engine and gearbox mounts

Fueling wise, im using '02 GSXR750 throttle bodies with omex 600 and in the process of ordering parts from DanSt to space them and make it all fit. Now is where I'm starting to struggle. The standard duratec injectors are meant to flow 180cc- 200cc or so depending on which search you do. These are supposed to be good for around 185 bhp. The standard GSXR injectors in the bodies are 240-270cc(again depending on where you read) Now here are my numerous questions:

1.Can anyone else with a similar set up give a rough ballpark BHP figure for bike throttle bodies and a freeflowing exhaust on the 2.0 duratec(useful if it was the higher flowing head 150bhp version) so I can size the injectors?

2. from online calculators, if I was making say 180bhp, I would need a flow rate of around 300cc at 3 bar, this doesn't tie in with the standard injectors BHP potential?? Danst also does a GSXR throttle body kit with the same TB as I have and lists it as "good to over 200bhp" with the standard injectors. Again this doesn't work out on any of the fuel calculators unless its with much higher fuel PSI

3. How much difference does it make to power and torque running the injectors in the standard head port rather than the TB? This would be an easy solution as there are lots of options for head injectors that will cover my power level and use the std fuel rail, however if its going to cost quite a bit of power ill look to use the TB mount point and the standard GSXR injectors or upgraded ones if necessary

4. How do people deal with a fuel return line? Both the GSXR and Duratec fuel rail dont have returns on them.

Sorry for all the questions and thanks in advance

Gavin

omega 24 v6 - 19/12/15 at 11:00 AM

In answer to question 4 I used a gsxr in tank fuel pump which is self regulating in pressure and just dumps the excess fuel back internally into the tank.

gav2612 - 19/12/15 at 11:23 AM

Thanks Omega. I did look at the GSXR pump, but wasnt sure how to best fit it. Did you cut a hole in the base of the tank to mount the pump to?

MikeRJ - 19/12/15 at 11:36 AM

quote:
Originally posted by gav2612
2. from online calculators, if I was making say 180bhp, I would need a flow rate of around 300cc at 3 bar, this doesn't tie in with the standard injectors BHP potential?? Danst also does a GSXR throttle body kit with the same TB as I have and lists it as "good to over 200bhp" with the standard injectors. Again this doesn't work out on any of the fuel calculators unless its with much higher fuel PSI

In my experience most of the online calculators give ridiculously large injector sizes. According to these calculators, many OEM injectors seem to be undersized for the original engine, so I don't really trust them.

Worst case the GSXR injectors flow only 20% more, but if you are aiming for 180bhp this is a 20% power hike so the bike injectors should be more than adequate (bearing in mind the original injectors would never be running at 100% duty cycle anyway).

quote:
Originally posted by gav2612
3. How much difference does it make to power and torque running the injectors in the standard head port rather than the TB? This would be an easy solution as there are lots of options for head injectors that will cover my power level and use the std fuel rail, however if its going to cost quite a bit of power ill look to use the TB mount point and the standard GSXR injectors or upgraded ones if necessary

It depends on how long your manifold is, the further the injector is from the valve the better the power potential in theory (which is why very high performance engine use shower injectors). In practice if you manifold is fairly short (and most bike throttle body conversion make the manifold far too short) then it will make very little difference.

quote:
Originally posted by gav2612
4. How do people deal with a fuel return line? Both the GSXR and Duratec fuel rail dont have returns on them.

Plenty of locosts have used return-less systems, and plenty of car manufacturers are now using them. Obviously there is a return from the regulator, but it's part of the pump inside the tank on the OEM systems. If you went this way it would simplify installation. If you want an external pump, then you will need an external regulator and return line, but you still only need a single line from the regulator to the fuel rail.

[Edited on 19/12/15 by MikeRJ]

gav2612 - 19/12/15 at 12:11 PM

Thanks for the replies and some really useful info. I think I'll work towards using the standard GSXR injectors for a kick off then and see how it goes duty cycle wise when I get it mapped. The in tank regulator solution sounds like a great idea and it would certainly simplify things. Is there an easy way to fit a pump with an internal regulator to the tank? Ive looked at the one from the GSXR, but it looks to require mounting through the bottom of the tank with an external hole cut in the tank.

omega 24 v6 - 19/12/15 at 12:34 PM

Yes I cut a hole in the bottom and made like a small sump to sit it in. I copied BIG RICHs photos to be honest he had a beatifull bit of work done on his. Search his photo archive.

Description

[Edited on 19/12/15 by omega 24 v6]

[Edited on 19/12/15 by omega 24 v6]

gav2612 - 19/12/15 at 12:42 PM

Found some useful info now by searching on this site for "in tank bike pumps" It seems most people are having a custom tank built with a fitting hole welded and threaded in. I already have a tank in situ, but wondering if I could fabricate a low level sump to fit the pump into that I could take to someone(to save blowing myself up!) to weld to the bottom of the current tank

Lol! you must have got in with your reply while I was writing mine!

[Edited on 19/12/15 by gav2612]

neilp1 - 19/12/15 at 03:24 PM

Can't answer all your questions but
I run GSXR 1000TB Omex 600 - injectors are ST170 and in head with the TB injector ports blocked off. 189BHP. Fuel rail was bought from AT power

mackei23b - 19/12/15 at 03:32 PM

I've got a Duratec 2L on jenvey 45mm throttle bodies and an MS3 to control the ignition and fuelling, I've also gone for ST170 injectors 315cc flow rate comes to mind.

I'm using the injector ports in the head with a standard ST fuel rail with a 'dead head' configuration.

Dead Head

Description

Cheers

Ian

[Edited on 19/12/15 by mackei23b]

[Edited on 19/12/15 by mackei23b]

[Edited on 19/12/15 by mackei23b]

big-vee-twin - 19/12/15 at 05:20 PM

I have Jenvey ITB's with dual injectors running on MS2.

It was set up by Bailey performance and acheives 193 BHP.

My fuel rail has an open end with tank return bought from at power.

I also have a Fastdan Duratec inlet manifold with gasket and flouro lined silicon connectors for sale if your interested - now surplus to requirements.

[Edited on 19/12/15 by big-vee-twin]

gav2612 - 19/12/15 at 11:41 PM

Thanks for all the great info guys. I like the look of the dead head system and it would save having to construct and weld a sump to the existing tank. Any downsides? I assume the HP pump would be at the base of the tank with the pressure return straight back in to the tank? I Thought about ST170 injectors if I was going for the injectors in the head as they're buttons to buy and should flow enough. Can they be used with the standard duratec fuel rail?

And yes VTwin I'd be very interested in the manifold you have. What size of connector pipes is it you have and how much were you thinking?

Gavin

gav2612 - 20/12/15 at 12:03 AM

More google searching on "dead head fuel systems" this time!
I'm thinking I could run the current LP pump to a swirl pot in the boot. Use a HP pump From there to the pressure regulator with the return back in to the tank and use the current fuel line in the transmission tunnel to feed the rail. The swirl pot would save any fuel surge issues And that would keep all the extra plumbing at the rear of the car and out of my very cramped engine bay. How does that sound?

[Edited on 20/12/15 by gav2612]

neilp1 - 20/12/15 at 06:32 AM

quote:
Originally posted by gav2612
More google searching on "dead head fuel systems" this time!
I'm thinking I could run the current LP pump to a swirl pot in the boot. Use a HP pump From there to the pressure regulator with the return back in to the tank and use the current fuel line in the transmission tunnel to feed the rail. The swirl pot would save any fuel surge issues And that would keep all the extra plumbing at the rear of the car and out of my very cramped engine bay. How does that sound?

[Edited on 20/12/15 by gav2612]

Thats the set up I have

big-vee-twin - 20/12/15 at 01:24 PM

It's a GSXR 750 set up you can see pics in my archive.

I will send you a U2U.

mackei23b - 20/12/15 at 01:34 PM

quote:
Originally posted by gav2612
More google searching on "dead head fuel systems" this time!
I'm thinking I could run the current LP pump to a swirl pot in the boot. Use a HP pump From there to the pressure regulator with the return back in to the tank and use the current fuel line in the transmission tunnel to feed the rail. The swirl pot would save any fuel surge issues And that would keep all the extra plumbing at the rear of the car and out of my very cramped engine bay. How does that sound?

[Edited on 20/12/15 by gav2612]

Yes, very similar, I had the high pressure pump in the tank (Standard Caterham Fitment) and a return line to the tank.

Cheers

Ian

big-vee-twin - 20/12/15 at 06:12 PM

I have just one hp pump, fed by a sump in the tank with a return to the tank , simple and works really well.

gav2612 - 28/12/15 at 12:09 PM

Any tips on where I would find a pressure regulator for a deadhead system as per mackei23b's picture? All of the ones I can seem to find are one inlet(or 2 inlets?) with a return line so to fit between the end of the rail and the return to the tank. I presume I would need one with an inlet from the fuel pump, an outlet to go to the fuel rail and a return line to bleed off any excess pressure to the tank? Alternatively, I could just use a GSXR pump If I was to go down that route, what sort of HP will they flow enough to support?

gav2612 - 28/12/15 at 01:57 PM

Actually, have been looking at it again. Has anyone heard of running a dead head system with an inline pressure regulator T'd off the fuel line between the high pressure pump and rail? Would that work?

40inches - 28/12/15 at 07:09 PM

quote:
Originally posted by gav2612
Actually, have been looking at it again. Has anyone heard of running a dead head system with an inline pressure regulator T'd off the fuel line between the high pressure pump and rail? Would that work?

That's what I have done, bit cramped in the engine bay

Description

gav2612 - 29/12/15 at 09:36 AM

Thanks 40 Inches. was there a reason you did it that way rather than have the pressure regulator on the far end of the rail and back to the swirl pot?

I was thinking of all of the plumbing in the back beside the tank, that way I can use the original fuel line down the transmission tunnel to the rail. The boot if you can call it that wont really be used for anything. It would keep the engine bay a bit cleaner and saves running anything more than a return line to the tank from the swirl pot which is only 40cm or so. I've added a picture below of how I was proposing to run the T-Piece. Running an external pump would allow me to accurately select one which suits the required flow rate as well

I also like the idea above of simply welding a small sump on the bottom of the tank for an in tank pump, but the tank already sits pretty low as is so not the best option. I have read elsewhere of running an in tank bike pump submerged in a swirl pot and it working ok. That would simplify my plumbing, but i'm struggling to find accurate info on how much a GSXR1000/1300 pump flows and how much HP it would support.

Thanks again everyone for guiding me through this, and no doubt a hundred other questions i'm going to have!

Description

[Edited on 29/12/15 by gav2612]

mackei23b - 29/12/15 at 07:44 PM

Hi there, I used a jenvey fuel regulator housing and a standard Bosch 3 bar regulator

Now with a pic below:

Fuel Rail

The return line is the vertical braided hose at the bottom.

Here is link to the car in action....

https://www.youtube.com/watch?v=-CoWMNCJj8Q

Cheers

Ian

[Edited on 30/12/15 by mackei23b]

gav2612 - 1/1/16 at 11:10 PM

Thanks Ian and very clean looking build in the video. Did you manage the 200hp without any cams?

mackei23b - 24/9/20 at 12:41 PM

By way of update - it was mapped at 210hp - though I know rolling roads may vary