LSA w/adapter plates - how bad, and where?

[blindsquirrel]

LSA on cathedral port heads... the issues the adapter plates cause, where does it typically have problems? Is it something you would notice with a loosey-goosey non-lockup converter (like 3800-3900 loose)?

[edcmat-l1]

I've done a few. They all seemed to have tip in stumble, worse when cold. Had to use transient fueling to cure them which in most GEN4 stuff you never have to touch when everything else is right.

[smokeshow]

Any event that requires a substantial amount of fuel injected that wasn't needed before.

[blindsquirrel]

I'm trying to weigh up whether it's something that would be tolerable in my hot rod El Camino if I were to swap it, where it probably wouldn't be tolerable in my nice cushy Envoy.

[edcmat-l1]

I'm trying to weigh up whether it's something that would be tolerable in my hot rod El Camino if I were to swap it, where it probably wouldn't be tolerable in my nice cushy Envoy.

I'm pretty picky about driveability. I do always aim for as stockish as possible manners. None of the vehicles I've done with this setup drove quirky afterwards. It just took some extra effort and some changes that aren't exactly typical.

[RDF1]

I'm trying to weigh up whether it's something that would be tolerable in my hot rod El Camino if I were to swap it, where it probably wouldn't be tolerable in my nice cushy Envoy.

Ive got a Yukon here with a 370ci, 317s, adapters, and a LSA Blower.
Its been giving me issues left and right..
Main one now is hot idles great but cold start it idles good but goes lean with any throttle. Wait for it to warm up and runs great.
Already been thru 3 X Links with it too

[edcmat-l1]

Ive got a Yukon here with a 370ci, 317s, adapters, and a LSA Blower.
Its been giving me issues left and right..
Main one now is hot idles great but cold start it idles good but goes lean with any throttle. Wait for it to warm up and runs great.
Already been thru 3 X Links with it too

That's the main issue. Cold tip in stumble. Dial in the VE or VVE real close. I make the tip in area intentionally "rich" (numerically higher). Then from there concentrate on the transient fueling and it'll clean up.

[blindsquirrel]

With what injectors - OE LSA with the angled spray (which is really bad combined with the adapters), or conventional straight spray?

[RDF1]

That's the main issue. Cold tip in stumble. Dial in the VE or VVE real close. I make the tip in area intentionally "rich" (numerically higher). Then from there concentrate on the transient fueling and it'll clean up.

Ive never had to mess with Transient so i have no idea where to start there.
Warm idle, cruise, medium throttle and WOT VE is very close. Less than 4% error.
But that cold tip in is killing me.

[RDF1]

With what injectors - OE LSA with the angled spray (which is really bad combined with the adapters), or conventional straight spray?

ID850s is what he has in this one.

[smokeshow]

I'm trying to weigh up whether it's something that would be tolerable in my hot rod El Camino if I were to swap it, where it probably wouldn't be tolerable in my nice cushy Envoy.

The only modified setup I've found acceptable is the LSA with ID injectors on rectangle port heads. No cathedral port adapter setup meets my expectations...simply cannot deliver the fuel properly. It's always subjective though...some people can deal with performance others might find unacceptable.

[blindsquirrel]

Well I don't want an iron block since it'll never be a 1000+ HP deal, and anything aluminum and 4" or larger bore is $1500-2000 more than the 5.3 I found for cheap which is already 24x (it's the same LH6 as in my Envoy), and is a complete drop-out with E40/T42 harness and everything... IMPASSE.

[RDF1]

Well I don't want an iron block since it'll never be a 1000+ HP deal, and anything aluminum and 4" or larger bore is $1500-2000 more than the 5.3 I found for cheap which is already 24x (it's the same LH6 as in my Envoy), and is a complete drop-out with E40/T42 harness and everything... IMPASSE.

Have you looked for a used TVS1900 made for the silverados?

[blindsquirrel]

I already have the LSA, CTS-V lid, LS9 fuel rail, and other misc parts. All bought before I knew about this issue.

[edcmat-l1]

With what injectors - OE LSA with the angled spray (which is really bad combined with the adapters), or conventional straight spray?

ID injectors always.

[blindsquirrel]

Any thoughts on mods to the adapter plates to unblock the injectors? Make that notch in the upper right corner deeper, even extending it into the cylinder head if necessary?

A thinner plate, like 1/8" or less, would be better for injector positioning but worse for airflow, I think the injectors are probably more important. Port mismatches don't have as big an affect as most people assume.

[edcmat-l1]

I personally have never built one. I've only tuned them. Maybe half a dozen of these exact setups. Had issues on a couple of them with drive system brackets, alignment, that kinda stuff. Tune wise they all came out about the same. I always at least rough in the VE or VVE and all of them seem to come out with the same tip in issue. I've done these combos with P59, E40s and E38s that I can remember specifically.

[RDF1]

I already have the LSA, CTS-V lid, LS9 fuel rail, and other misc parts. All bought before I knew about this issue.

Would you be interested in selling it to get a bolt on TVS1900 kit?
This Yukon has eaten 3 belts and slings the belts off if it barely touches the rev limiter if it spins the tires.
Ended up putting a Cummins tensioner on it for him and so far its been fine but fighting belt slip now with only 16psi boost.

[blindsquirrel]

16 PSI with a 1.9L? What's the pulley ratio?

[edcmat-l1]

16 PSI with a 1.9L? What's the pulley ratio?

Probably 9.5/2.5.