3500 swap questions

[Jonpro03]

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

[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

[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

[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.

[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.

[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.

[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

[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.

[lilredtruck]

Hi, Guys,
I'm in the midst of putting a 3500 into my Isuzu P'up, FWD engine into RWD. Many challenges. What solution do you have for using the 3500 injectors with a 3100 fuel rail (return rail)? 3500's are 1/2" too short. I thought I saw an answer to this some time ago but can't find it. I have a wiring harness from a '94 Beretta, per SuperDave, as well as the complete 3500 harness, PCM, TB. Need to modify the TB to eliminate ETC. Any ideas?
Brian

[bob442]

i wonder if some material could be machined off the top of the pistons

[bszopi]

ben told me something about 3.6 DOHC pistons but wasnt clear on who sells them

As of right now, only GM. Diamond will most likely be making them in the near future though.

[bob442]

is there any pistons avalible to raise the CR on a 3500 block? ben told me something about 3.6 DOHC pistons but wasnt clear on who sells them or what combo will make what.

[Weatheralls Auto]

Well, they look like the same style anyways, not sure if they are the same or possibly upgraded.

I had never thought about the U/X vans having LX9 until one of my customers came in this afternoon with one lol.

Never seen any mention of them, just the G6 and Malibu.

At least this give me more sources for parts etc,(Montana SV6, Terraza, Uplander ) if going with header, the exhaust mani wouldn't matter anyways.

[robertisaar]

Exhaust Manis are much more like the 3400 LA1 ?

if that's true, that's why. the malibu 3500s got decent "manifolds".

[Weatheralls Auto]

To be honest, I did not reread this entire thread to see if this is mentioned but,
I see so many talk about the LX9 from 04-06 G6 & Malibu Vin 8

Why no mention of the LX9 vin L from the U & X vans?

It also uses the Powersteering pump and I think the Exhaust Manis are much more like the 3400 LA1 ?