3500 (LX9) swap into a Fiero

[Joseph Upson]

I have a 16lb set which is in my 2.8L, I have a 19lb set that came with the 3100 fuel rail. I also have a set that came with the 3500. I am under severe cost constraints and can not afford to purchase a set of 24lb injectors to use with the 3100 fuel rail. I need a solution that is around $50. I believe I can get a suitable adjustable FPR for around that price. Joseph Upton has already proven a modified returnless system can be done. I have also talked with a very knowledgable person from the 3800SC camp that has converted returnless systems on a regular basis with no drawbacks whatsoever. It also allows me to use the stock components from the 3500 that I already have in my possession.

Avoiding any changes that move backwards in technology is a good thing whenever possible. The newer the parts the better. The adjustable regulator is also an attribute and having the ability to attach an inexpensive pressure gauge to it is another plus if ever you have a starting problem and have to diagnose. It's not a complicated accomodation at all, you're basically attaching lines to the regulator instead of the rail and running one line instead of two to the engine.

[IsaacHayes]

If you got it figured out and the parts aren't that expensive go for it. Used 24# from a DOHC or something do show up every now and then for sale though.

[Joseph Upson]

If you got it figured out and the parts aren't that expensive go for it. Used 24# from a DOHC or something do show up every now and then for sale though.

The problem with DOHC injectors is that the spray pattern is specific for the DOHC valve design with a wider spray pattern instead of conical which is used on single intake valve ports. They will work with no problem however the spray pattern will result in more fuel being sprayed towards the walls of the intake runner. I forgot the degree of the angle but the DOHC injector was designed so that fuel would be sprayed evenly at each intake valve in an oval shape to hit both valves rather than the narrower conical pattern aimed at a single valve.

[IsaacHayes]

Ah yeah, forgot about the dual spray pattern.

[flimbob]

Looks like there are several adjustable FPRs on EBay. Has anyone had any experience with any of these?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=200434481013&viewitem=&sspagename=STRK%3AMEWAX%3AIT

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=370234350106&viewitem=&sspagename=STRK%3AMEWAX%3AIT

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=370267283406&viewitem=&sspagename=STRK%3AMEWAX%3AIT

I also found that the head of my oil dipstick is broken. Does anyone know if the 3100 or 3400 dipsticks are compatable?

[SappySE107]

Those won't fit the fuel rail. I sell one that replaces the stock unit.

http://wot-tech.com/shop/all/adjustable-fuel-pressure-regulator/prod_135.html

I also have the AN fittings for a remotely mounted AFPR setup.

http://wot-tech.com/shop/all/an-6-fittings-for-3x00-fuel-rails/prod_132.html

[Superdave]

If you run your 19's @ 55 PSI (22.5 lb/hr) they will work if the engine is stock.


the dipsticks are all the same for the gen3 engines, if you go to the yard grab a few because it's common for them to break.



FWIW, we ran 3.4 DOHC injectors in a 3400 with a cam and ported heads with no problems. Getting ready to put them in a stock 3500 in a few weeks.

[Joseph Upson]

If you run your 19's @ 55 PSI (22.5 lb/hr) they will work if the engine is stock.

the dipsticks are all the same for the gen3 engines, if you go to the yard grab a few because it's common for them to break.

FWIW, we ran 3.4 DOHC injectors in a 3400 with a cam and ported heads with no problems. Getting ready to put them in a stock 3500 in a few weeks.

True they work Superdave, I believe in this situation he's better off working with what he has instead of opting for what must be at least 10 yr old technology and parts for that matter if the last production year of the 3.4 DOHC is 1996. It's tough enough discouraging Fiero swappers from switching out aluminum heads for cast iron heads on roller cam blocks.

[Superdave]

True they work Superdave, I believe in this situation he's better off working with what he has instead of opting for what must be at least 10 yr old technology and parts for that matter if the last production year of the 3.4 DOHC is 1996. It's tough enough discouraging Fiero swappers from switching out aluminum heads for cast iron heads on roller cam blocks.

lol, but there is quite a difference there... iron heads are the devil, old but good injectors will still perform well as long as they are clean.


My Sy/Ty injectors still work fine and they are 19 yrs old.

[flimbob]

Ben,

If I win the $75 certificate for this month's raffle, I could then fit your adjustable FPR in my budget!

[ForcedFirebird]

iron heads are the devil

ROFL!!!

[flimbob]

If you run your 19's @ 55 PSI (22.5 lb/hr) they will work if the engine is stock.


the dipsticks are all the same for the gen3 engines, if you go to the yard grab a few because it's common for them to break.



FWIW, we ran 3.4 DOHC injectors in a 3400 with a cam and ported heads with no problems. Getting ready to put them in a stock 3500 in a few weeks.

That's good input on the 19's @ 55 PSI. I thought I read somewhere ( here on the forum ) that the stock 3400 FPR is 55 PSI.

[flimbob]

SuperDave,

You had posted info on using the 19lb injectors in the 3500 Swap thread on the V6Z24 forum. Since my fuel rail was off a 2001 Malibu that had Multec 2 injectors, wouldn't the FPR be the 52~55 PSI type?

[SappySE107]

Yes it is. 2000+ are all 55psi regulators.

[flimbob]

Seems like I have a 55 PSI FPR, so I'll go the modified returnless route. This will enable me to keep the 3500 fuel rail and injectors.