3500 swap questions

[wasas9]

You can use multec 2 injectors from a 2000+ 3400 engine along with it's fuel rail and fuel pressure regulator.

It will need to be tuned though for best performance.

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[bob442]

As i am finally starting a hybrid swap, whats the best way to tell if i have 22lb injectors or 19lb, i remember browsing a thread and someone said that GAGT's have 22lb injectors, but do all 3400's have 22lb injectors. my other question was answered about using the 3400 rails on a 3500, and now i'm just curious, if i upgrade the injectors, and run my car with a cam, could i stand a chance of hurting the motor? or just loose potential of power till its tuned?

Bob

[3400-95-Modified]

You always run a chance of hurting a motor when it doesn't know whats attached to the ECM, granted it will correct as much as it can, but WOT will most likely be way off.

I'm using 3400 rails on my 3500 top end and have been for years with NO issues, the give about a 1/8th more of compression when installed since they sit just a bit higher, but if your really concerned about them being too tight you can make spacers so the rails aren't applying any pressure... I've never had an issue with it.

Also yes large port 3100 and 3400's from 00 to 05 IIRC are all the same 22lb/hr@55PSI setup, granted p/n's may have changed due to better injector design over the years, but I think they all flow the same amount from 00 to 05. 99 and older 3400's were 19lb/hr and 3100's were 16, both at 43.5PSI. BTW 19lb OBD1.5 injectors should flow ~22lb/hr at 55PSI.

[boomofdoom88]

I just did a 3500 swap into a 00 Grand Am. I used 28 lb trailblazer injectors in the 3400 fuel rail. Dimensionall the same as stock. And at 55 psi is pretty close to the stock 24 lb 3500 injectors which are of course too short to use with the 3400 rail. Probably not perfect but idles and revs fine with a stock 3400 tune. Buying hptuners come spring to tweak it and find out.

[SappySE107]

The trailblazer injectors are 5 lbs more at 55psi than the 3400 injectors. A retune is going to make a big difference. 21.31 are stock injectors, and 26.37 for the trailblaser at 55psi.

[3400-95-Modified]

As Ben noted your ECM thinks it has 21lb/hr injectors attached to it. The stock flow rate of the motor vs what your running will only prove that you have an injector with enough flow to support the engine in the end, it doesnt mean your tune is anywhere near close.

Ben are those tested flow numbers? Because that would really explain why I've seen some notes of the Trailblazer injectors not flowing at 28lb's unless your at 62-63PSI

[RedBird]

everything from your 3100 is a direct swap over to the 3500, at least the accessories. i find it hard to believe they'd take the water pump off a genIII motor, but even if they do it's only 25 bucks, and, you'd want to get a 3500 style one anyway, same bolt pattern and fit but it's a better design.

anything that came stock with a genIII motor i'd say is totally worth getting a 3500 to swap. it's an amazing gain, especially over a small port 3100, and almost a direct swap. the work required vs trying to get those same power levels from the 3100 makes it totally worthwhile

[Jonpro03]

FWIW, I never changed the waterpump on my 3500. The powersteering pump bolted right up.

[elementdrummer]

There is a TON of information on a bunch of different cars for this swap. Its hard to find the right pages or my 1999 grand am 3400 to 3500 swap i have started.

Basically heres where I stand, hopefully someone will correct me if I am wrong.

Using 3400 plenum with 3400 gaskets will be port and polished for better flow. This will retain the grand am TB which will be upgraded to 62 or 65mm throttle body.

Using 2000+ 22lb injectors as well as 2000+ FPR and my origional 1999 3400 fuel rails along with new plugs and wires for my 3400.

Using all of 3400 accessories including ignition control module and coil packs. No major issues mounting up besides a/c not having 1 bolt hole it seems.

Will be missing 1 bolt for tranny to engine mount unless I customize. i will use 3500 mounts but use the 3400 oil pan to retain my sensor the 3500 lacks.

Get a WOT tech external crank trigger to solve the 24x sensor. Swap over the arched 7x sensor from my 3400.

I believe most of the other sensors will work so i will leave them in he 3500, may have to do some wiring, but its all the same signals.

Since i am a 99 grand am i will swap my cam sensor over to the 3500.

Which is best to use for rebuild 3400 metal gaskets? or factory 3500 gaskets or is there a felpro that will work? I may do a cam and port and polish the heads as well.
Use 3400 exhaust manifold. hopeully try to score some S&S headers but that is unlikely... may just have to use stock thats my only other option it seems.

Will flatbed car to shop to get a custome tune.

Need some expirience to reply back, will be getting new motor this month, I want to be part of this awesome 3500 swap group haha

[bszopi]

i will use 3500 mounts but use the 3400 oil pan to retain my sensor the 3500 lacks.

Get a WOT tech external crank trigger to solve the 24x sensor. Swap over the arched 7x sensor from my 3400.

You can not use a 3400 oil pan on a 3500 for multiple reasons, the main one being that the holes don't match up. The other being that the 3500 oil pan is clearances in several places for the connecting rods.

I think you have the crank sensors mixed up: 7x is the in-block one (which can not be used with the newer 3500 trigger, hence the WOT-Tech external), and the 24x is the one mounted on the timing cover.

Welcome to the site!!