Spectre plenum install on 454 TBI

[JonnyG]

To any of you who have installed one of these plenum's with a single hole in the top how does one mount them on a TBI with 2 studs?

[JonnyG]

Well I guess this isnt a common issue, Spectre Performance 4215 TBI "S" Stud Air Cleaner is required to install that plenum on a dual stud air cleaner which my 94 TBI uses. Hope this helps someone else

[Oz]

True, not a common issue as  there's not a lot of people here with that tbi.  Most I've seen have another brand. Can't think of the name right now though.

[JonnyG]

Am I chasing the wind  trying to "upgrade" the intake? I read somewhere that the factory air cleaner is crap and even just flipping the lid will add an extra 8HP stock or something of the sort. Looking for real world experience here as I didnt grow up around this stuff and really dont know.

[Eyez Open]

If your looking for a performance improvement yeah..chasing the wind does come to mind. What you can do is send your prom/software to OBD diag, they can burn you a new program that will enhance your engine quite a bit. Just give them a call and see whats up...maybe about 200 dollars..

Hmm looks like inflation has hit tuning services to....go figure that. OBD is perhaps the best in the business.. mefi and obd are very much like twin brothers...only one went bald.   :)rotflmao

https://obd2allinone.com/mefituning.asp

[eXodus]

That intake elbow is usually not the limiting factor on a 454.

You need to feed cold air to that beast.  https://harristuning.com/Tbi/recommended-454/

Banks sells a kit to accomplish that:
https://bankspower.com/products/cold-air-intake-49081-1996-2000-gm-454-class-a-motorhome-7-4l-p30

Or
https://performancetruckproducts.com/banks-motorhome-ram-air-cold-air-intake-system-oiled-filter-95-gm-454-motorhome-efi-electronic-fuel-injection/

I you can DIY with a few ducts from your favorite home improvement store.

[JonnyG]

Thanks for the advice, much appreciated. Is the 454 really tuned that poorly from the factory? You'd think they would have designed it for its use, I don't really know much about tuning but will contact those guys and see what they say
Currently im looking for cheep and cheerful upgrades as this I'snt exactly a looker anymore but also would like to do things half way right, I've gone down the spectre path so i think i will wrap it up with some ducting and a cone filter and call it a day. The factory air cleaner is crap isnt it? Banks stuff looks great albeit expensive but they seem to be not selling the older 454 stuff anymore, mostly 96 and newer now for exhaust anyway.

Im not looking to blow the wheels off this thing by the way, just maybe add a little pep and efficiency. That harris tuning link it some sound advice

Is this a power plant a lot of you guys are just leaving alone and keeping stock or are there some things that everyone seems to do?

Also a bit of a gear head family friend told me I should be running premium in this thing to squeeze out all the power possible, that's ludicrous isn't it? Low compression engines dont really take much advantage of higher octane fuels, do they?

[eXodus]

80s and 90s where terrible for tune thanks to fast rising emission requirements.

GM was just cheap and did only put that TBI injection system on, so you get like 215-230hp   from late 80s to 1995 then later in the 90s you get the 454 / 7.4L Vortec with fuel injection and that same engine makes 290HP.

The round airfilters are no good for flow - getting a lot of hot air.  Not sure what your model has as a filter.  The square filters a decent.
Those Banks sets are pretty good, you can make them fit, and you find them on eBay once in a while.

Very few things you can do to that engine to make more power cheap.  Some got lucky and found a junk yard 7.4L Vortec from like a 1997-2002 and they swapped the top end from that engine on their old 454.  That can be done for a few hundred bucks and 2 weekends in bending, swearing and crawling.

Otherwise, just regular tune up, get it cold air, get the Chevy Express Fuel Pump.

leave early, just drive slow and enjoy the view 

[Eyez Open]

Actually for carbed engines there is a lot of room for improvement, it is the simplistic ease of changing the timing and being able to do it in minutes and the carb to... both are intertwined. Most call this tuning my own opinion is maximizing engine fuel combustion and that is dependent on cylinder size and compression ratio..its easy to go to far or not enough. And it only takes a minute of to to correct any miscalculations with a carbed engine.

Now as to TBI that is another story, it takes quite a while to build a program for a engine type and then just as a carbed engine one checks out the work thru actual operation..it to is a trial and error process. Carbs engines may take a hour to really tune them...TBI could take hours and hours. What this all means you do it once and your done...No retunes simply because of the cost and transportation/down times. The new tune will be conservative simply due to possible turn around times...think retune.

I made a reference to OBD diag simply because they have done hundreds if not thousands  of 454's mostly marine and have a great deal of experience with these engines, more than probably a tune is probably just sitting on a shelf waiting to be downloaded in to a ecu/prom.

Right now i dont believe i would invest into a old rochester TBI...Its time has come and gone and along with that parts are becoming rare and expensive...Now all of this is a opinion make no mistakes.

This type of conversation centers around 454 smogged engines, generally speaking they have highly retarded ignition timing, very low compression ratios, and very large combustion chamber's. Those variables allow for rather large modifications to the combustion processes, due to sheer size of the 454 the gains by percentage are quite impressive, and can be quite destructive if done incorrectly. And then there is all the changes that has been done to gasoline refinement...