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Discussion Starter · #1 · (Edited)
Hello! I'm doing some research for my 91 wagon on TBI vs TPI and swapping them, engine management for TPI, ect. I don't have any parts yet, as I'm still trying to figure the logistics out first. I had Dynamic EFI recommended to me by a member here as a method of tuning my TBI, and Dynamic EFI says their ECM will control both TBI and TPI. With this ECM a TPI should be be a (somewhat) straightforward swap from TBI, right? I understand that I'll need things like a FP, harness, ect. But so far I'm not seeing any major hurdles with this idea, but maybe I'm missing something? Also, it'll likely go on a mild 350 and not my current L03

I would absolutely love to have a TPI setup on my wagon! I think the TPI looks super neat, and it's supposed to be a torque monster (on a properly set up engine). It just doesn't seem to have been as common a swap over the years, so there's not a ton of info on it.

Thanks in advance for your feedback!
 

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The reason you don't see this is because it just doesn't make any sense.

If you like the TPI, that is one thing. I won't knock you for doing what you want with your own car.

At my local self-service yard, I can grab any LS engine I want for $199 on any day of the week. LS aftermarket support is as good as it gets, and the bottom line is that you will make more power for less money.

Once the car is set up for LS, then replacing junkyard engines is like replacing a maintenance part.
 
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While more work, if I was entertaining TPI , I think I would look at using the GM "411" PCM .
Been done more than once by the F body people.
 

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Discussion Starter · #4 ·
I did very seriously consider just sticking an LS in the car!
But I do like the TPI and just small blocks in general. I'm not looking for a ton of power, mostly just a good amount of torque so the big wagon can get out of its own way.
And since it's not my daily, I thought TPI would be a neat setup to try and make work.
But, I still haven't ruled out the LS route, it's kinda just a backup in case all my crazy ideas won't work.
 

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Discussion Starter · #5 · (Edited)
While more work, if I was entertaining TPI , I think I would look at using the GM "411" PCM .
Been done more than once by the F body people.
Would this allow a coil near plug setup?
 

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411 pcms were used in both distributor - single coil applications and coil near plug.
You could do either.
It would depend on what engine setup you mimic.

Without research , I would guess keeping a dist would be cheaper as it would be all junkyard GM vortec stuff.

8 coil, you are " pretending" you are an LS using something like the Torquehead front end parts.
 

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Discussion Starter · #7 ·
I'd probably just stick with a good ol distributor then.
 

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I did very seriously consider just sticking an LS in the car!
But I do like the TPI and just small blocks in general. I'm not looking for a ton of power, mostly just a good amount of torque so the big wagon can get out of its own way.
And since it's not my daily, I thought TPI would be a neat setup to try and make work.
But, I still haven't ruled out the LS route, it's kinda just a backup in case all my crazy ideas won't work.
Just based on parts availability and aftermarket support, I think the TPI sounds like a headache that will be regretted. I would only consider building a TPI engine if it were original to the car.

With that said, some people shy away from easy. Some people enjoy a challenge, or being different.
 

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You can check these guys out:

I have one of their intakes that I am going to install on my LT1. I was not looking for top end either, just more torque for quicker passing on the road and a little more surprise for people at stop lights. Ken that runs First Performance is a great dude to work with. Email him with what you are looking to do, he is super patient and realized that his products are a significant investment. He may be able to provide some suggestions/recommendations.

I cannot speak first hand at how well their products work or don't as my intake is still sitting in the box.

Good Luck.
 

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Discussion Starter · #10 ·
I've heard of First fuel injection, that would be pretty sweet!
It's Not exactly a budget option, but it's actually really not that expensive either.
And the price shouldn't matter as much since I'm planning on taking my sweet time to build a 350 for my wag since the car runs fine, so that's actually a great idea, I'll definitely consider that!
 
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Just based on parts availability and aftermarket support, I think the TPI sounds like a headache that will be regretted. I would only consider building a TPI engine if it were original to the car.

With that said, some people shy away from easy. Some people enjoy a challenge, or being different.
What are you talking about parts availability? have you ever heard of rockauto before? have you ever done a LS swap yet alone an engine swap or EFI swap not native to whatever you're working on? It's great you can get an LS engine for $200, this is not the reality for everyone. I would pay $2500+ for a complete engine with harness on average. Yes there are the occasional deals but not the norm. The nickle and diming is what adds up. Was thinking about LS swapping a buddies Cherokee, we gave up on the idea once we hit 10 grand and still had lots of other stuff to buy, granted the adapter plate to non-GM trans was an expensive piece.

OP, swapping to TPI is fairly straight forward. However I think it would be more looks than performance gains. Milage would improve with tuning over TBI. TBI will make more low end torque, TPI really shines in the 3000 rpm range. The TBI head with TPI induction is a fairly good combo. TBI heads get shitcanned all the time but they are actually a decent head if you're not trying to make a race car. I recently used them in an engine for my truck, nearly 400ft/lbs of torque below 3000 rpm with a rather mild 214/217 roller cam.

Anyway, first thing would be to acquire a full TPI setup either from the wrecker. you will need to be careful what intake base you get, corvettes and early F-bodies use the traditional intake bolt arrangements l while the later F-bodies used the centre intake bolts point up like your TBI intake. The other thing to consider is MAF vs MAP. The 90-92 upper intakes have a MAP sensor that bolts to the side as well as do not come with a 9th cold start injector. These are the years that i would look for. The more complete the better.

The multec injectors can go straight in the bin, south bay fuel injectors makes drop in sets that will work here. Will need to upgrade your fuel pump. TPI pump will work fine, mid-90s vortec pump even better. they are a drop in replacement and is a mandatory upgrade even for stock TBI. Fuel lines will need to be modified. TPI fuel lines enter on the front drivers side of the motor. i am use to the TBI trucks and have modified the stock TPI rails to adapt from the rear, but with the caprice you could probably buy adapters and stainless braided line and make something work with the stock line configuration.

Wiring. This will be pretty easy, your basically cutting off the TBI injector connectors are splicing in the TPI injector harness. You may need to lengthen IAC and TPS wires to reach the throttle body. As far as ECU goes you have already discussed my first choice,EBL you will need the "port" mod done. The other option, if you ever wish to goto a 4L60E or 4L80E down the road is the 94/95 TBI truck PCM. It can be easily modded to fire in Port injection mode, but tuning equipment will be required if you cant find a tuner. Let me know if you have any other questions.
 

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What are you talking about parts availability? have you ever heard of rockauto before? have you ever done a LS swap yet alone an engine swap or EFI swap not native to whatever you're working on? It's great you can get an LS engine for $200, this is not the reality for everyone. I would pay $2500+ for a complete engine with harness on average. Yes there are the occasional deals but not the norm. The nickle and diming is what adds up. Was thinking about LS swapping a buddies Cherokee, we gave up on the idea once we hit 10 grand and still had lots of other stuff to buy, granted the adapter plate to non-GM trans was an expensive piece.

OP, swapping to TPI is fairly straight forward. However I think it would be more looks than performance gains. Milage would improve with tuning over TBI. TBI will make more low end torque, TPI really shines in the 3000 rpm range. The TBI head with TPI induction is a fairly good combo. TBI heads get shitcanned all the time but they are actually a decent head if you're not trying to make a race car. I recently used them in an engine for my truck, nearly 400ft/lbs of torque below 3000 rpm with a rather mild 214/217 roller cam.

Anyway, first thing would be to acquire a full TPI setup either from the wrecker. you will need to be careful what intake base you get, corvettes and early F-bodies use the traditional intake bolt arrangements l while the later F-bodies used the centre intake bolts point up like your TBI intake. The other thing to consider is MAF vs MAP. The 90-92 upper intakes have a MAP sensor that bolts to the side as well as do not come with a 9th cold start injector. These are the years that i would look for. The more complete the better.

The multec injectors can go straight in the bin, south bay fuel injectors makes drop in sets that will work here. Will need to upgrade your fuel pump. TPI pump will work fine, mid-90s vortec pump even better. they are a drop in replacement and is a mandatory upgrade even for stock TBI. Fuel lines will need to be modified. TPI fuel lines enter on the front drivers side of the motor. i am use to the TBI trucks and have modified the stock TPI rails to adapt from the rear, but with the caprice you could probably buy adapters and stainless braided line and make something work with the stock line configuration.

Wiring. This will be pretty easy, your basically cutting off the TBI injector connectors are splicing in the TPI injector harness. You may need to lengthen IAC and TPS wires to reach the throttle body. As far as ECU goes you have already discussed my first choice,EBL you will need the "port" mod done. The other option, if you ever wish to goto a 4L60E or 4L80E down the road is the 94/95 TBI truck PCM. It can be easily modded to fire in Port injection mode, but tuning equipment will be required if you cant find a tuner. Let me know if you have any other questions.
WOW... Where do I even start?

First of all, you are in CANADA. It is YOU that is "not the norm". $2500 for a used engine with harness is absolutely insane, and nobody in the United States would ever pay that much. We have huge chains of self-service yards located all over the place. On Craigslist and Facebook you can expect to pay about $300-$500 for a running LS engine that is already pulled.

Have I heard of Rock Auto? My fridge is completely covered in their magnets.

Parts availability? You seem to be completely out of the loop here. You really need to do some research. LS engines are one of the most common and widely supported engine platforms in history. How many LS tuners do you think there are in the United States compared to TPI tuners?

Go on Summit, Jegs, Rock Auto, or anywhere else you want to look. Look at aftermarket performance parts for LS engines vs TPI engines. It's not even close. Go to any junkyard in the world... even in an obscure country like Canada... and tell me how many LS-powered trucks and vans are there. Then, tell me if you can even find one single Camaro or Corvette with a TPI engine. Is this a real discussion?

I know more people than I can count that have LS engines in their B-bodies, and 95% of them did not spend $10k to do it. The exceptions are the few guys who have bought brand new crate motors (LSA, etc.).
 

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what would he need for aftermarket parts? complete intakes can be had for cheap. I have bought 2 complete setups off Craigslist between $200-300 canadian over the last year. Unlike you I have done this swap more than once and have one lined up to do next year on a friends 92 gmc 2500. The OP seems to have a relatively stock engine, this is not some high performance monster where tuning is mandatory. A stock tune would be fine here. However tuning ALWAYS helps even a stock engine. Have you used EBL before? It was setup so the average car guy can load a tune, click a button to start logging and auto tune your VE tables. It's what I used when I started tuning over a decade ago and got a very driveable 375HP TBI Caprice with NO tuning experience. I am not trying to pick a fight here, but you have no business telling the OP what he should be doing. A TPI swap once parts are collected can be done in a weekend. an LS swap will be weeks, maybe even months to years down time. I have been there done that when it comes to this stuff and ALWAYS try to do minimal down time between projects. This goes for my own vehicles and friends & customers. Most lose interest interest after a few weekends of "spinning their tires". This is NOT suppose to be the goal of this "hobby" and I really hate when people who have watched YouTube videos and read a few "swap threads" think that swapping a completely different drivetrain is the only and best solution.

OP, there is a tuner a province away from me that does mail order tunes. I have never had custom stuff by him done only used stock "canned tunes" and they are noticeably better than stock. This is the option I recommend for people that do not want to go the DIY route, westersgarage.com
 

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Your post was such a pathetic mess that I'm not even going to touch it. You just ramble and ramble without ever making a single solid point.

you have no business telling the OP what he should be doing
You have NO BUSINESS making this statement. Who are you?

Seriously... Pick someone else to argue with.
 

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Discussion Starter · #15 ·
For reference I live in AZ and the typically 5.3 usually go's for around $700-$1500, with the pick a part charging about $600-$700 for complete engines. They're not typically Less, but occasional they are. I agree that $2500+ is a bit crazy, for a 4.8-5.3, but about standard for any "LS" engine (LS1, LS6, ect.)

I could probably afford an LS, but it's not my first choice. Besides I'm not looking for much power anywho. Not the personality of the car
 

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Discussion Starter · #16 ·
swapping to TPI is fairly straight forward. However I think it would be more looks than performance gains.
100% correct, I think TPI looks freakin cool!
If be perfectly happy with 300hp and 350-400 ftlbs. I don't think the wagon needs to be crazy fast, I just want it move its 4400lbs faster then it does now (not hard!).

Milage would improve with tuning over TBI. TPI really shines in the 3000 rpm range.
If this is the case, than great!

Also, I would very likely be tuning it myself. I have some experience tuning with my LT1, though I'm still try to learn as much as I can.

Plus, If I'm going that far with the engine, I'll be building a 350. It's not my daily so I can take my time and make it sweet!

Thanks for the help so far!
 

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Best way to get a cheap LS engine is to start calling cast iron Vortec truck engines LS's 😉

Further to your original plan ,
What about finding a 2001ish L31 core dropout from an express van.
Add your TPI intake and suitable heads.

Gets you,
your 350 to build
Your torque and visuals you want
The 411 pcm, sensors, crank wheel , front end cover etc.
An adaptable harness.
Depending on your trans choice, the 411 will control 60 and 80 E's
The above, just spit balling never done this
Reasons not to , based on experience , welcome.
 

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Best way to get a cheap LS engine is to start calling cast iron Vortec truck engines LS's 😉
Well, since you went there, now you need to explain. Is there an actual difference besides the letter designation? Don't forget that not all of the truck motors are iron.

A. How are the truck engines not LS engines?

B. What's the advantage of an LS7 over a built iron block?

TBSS guys are ditching their LS2's for iron blocks.
 

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"now you need to explain"
Oh well I better get on then :sneaky::sneaky:

They are are gen 3 and gen 4 small blocks.

In my humble opinion , the 3 digit code comes into play with the assembly, or the parts used in the assembly.
Case in point,
an LQ4 is a cast iron 6.0 gen 3
an LY6 is a cast iron 6.0 gen 4
an LS3 is an aluminum 6.2 gen 4
an L76 is an aluminum 6.0 gen 4


If you need to "hang" a designation on something, again in my opinion, you cant go higher than where the parts were used.
Sure call a stroked LQ4 a 408 LQ9, dont call it an iron LS

Sure in certain cases a cast iron block is worth the weight penalty.
Big boost, etc

But again , an LQ4 block is not a GM performance parts Bowtie block, is it?

The three cars in my driveway, so to speak,
Only two are LS powered.
G8 is an LS3 , a gen 4 6.2
Caprice is an LS7 , a gen 4 7.0
The third , a G8 , is an L76 , gen 4 6.0
It is not an LS , you can call it a LS2 but with LS3 heads, BUT really it is not.

LS7, while the block is specific , it is the sum of its parts.
Its like saying an LSA is just an LS9 with a smaller blower. Its not
Take away its ti rods and dry sump, it not "really"
an LS7 any more is it?
Build a kill aftermarket block , like an RHS, 7 liter with a bryant crank and aftermarket ti rods.
Better engine all around than an LS7, yes, but it is NOT an LS7.

"What's the advantage of an LS7 over a built iron block?"

Weight, bay to bay breathing, bore length, bore dia.
In a normally aspirated 7000 rpm 4.0 stroke configuration, I see it as superior.
( till it drops a valve)

So, to me the engines are
Gen 3 iron
Gen 3 alloy
Gen 4 iron
Gen 4 alloy

"TBSS guys are ditching their LS2's for iron blocks."
unless they going forced induction, I submit it would usually be for economic reasons.
Not sure I have seen someone running naturally asperated pull a prefectly running alloy engine out and "upgrading" to an iron block in a non boosted situation.
 

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Discussion Starter · #20 ·
G8 is an LS3 , a gen 4 6.2
GXP?



When someone says "LS" I usually assume any gen 3-4 engine regardless of iron vs aluminum block, doesn't mean it's not still confusing sometimes. The "proper way" would be to call LS's gen 3/4, or just by their RPO codes (LS1, LM7, ect.)
But it doesn't matter, since the entirety of the English language is screwed up anyway. Just sayin.
 
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