CA Legal F.I. Conversion Suggestions

[My85]

Since most of my questions are F.I. related I posted here vs the engine swap thread. Mods, please move if you think it's in the wrong spot.

I’m going to do a C.A.R.B. legal “engine exchange” and replace my 1985 5.7 w/CCC with a newer F.I. motor/trans. Unfortunately, I will have to swap out my current 700R4 because it is equipped with a 1985 only sensor that retards the timing when in O.D. The sensor started leaking and I just installed a bolt and ziptied the wires up out of the way. Smogging hasn’t been a problem since the techs aren’t looking for a computer connection to the trans. However, the referee will be closely examining my Blazer and the bolt is a no-go.
Requirements:
I’m looking for a reliable daily driver/road trip vehicle. I don’t need tire burning horsepower. I do want to be able to drive up to Tahoe, go over the Grapevine etc and not be stuck in the truck lane behind a motorhome.
Will TBI meet my needs or is it such old technology that I won’t be able to find parts in the next few years?
If TBI is still viable what years should I be looking for and can I use my current transfer case? (darn budget)
Would TPI be a better solution? If so, what years? At what point will I have to ditch my current transfer case? I don’t want to go so new that I will have to retrofit a bunch of sensors (fuel cap etc).
Thank you in advance for your suggestions

 

[dyeager535]

I'm not really up on CA stuff, it seems so complex.

TPI would be a good swap, but is it legal, since it only came in cars? If it's legal, I don't see a downside, except more injectors. All the emissions components are the same that I can think of vs. TBI, maybe even your '85 since EVAP is the main one. Problem with TPI is the fuel lines, but that is probably minimal compared to everything else. Realistically TPI is antiquated next to the LS-series stuff, so I've seen complete setups for ~$200 at swap meets in the last few years.

TBI would likely be fine, and would also be the easiest swap. Since the body is the same, wire length will be right unlike TPI. No brainer because everything will bolt up. I would say the '90-91 you MIGHT want to stay away from. The '90-91 will necessitate the transfer case from those years and swapping the instrument cluster, however it IS a better setup than the cable drive speedometer stuff from earlier years, and the 241 is at least a slightly better case than the 208.

 

[My85]

Thank you for your response. Yes, CA emissions law can be a pain. For example, I can't just install F.I. on my current engine. Legally, I have to install the newer engine/trans and retrofit any computer controlled devices, emissions related or not.

Thanks for the heads up about needing to swap the dash and the trans/transfer case on 90-91's.

I see your 87 is currently running TBI. Overall, how do you like it compared to your 85 TPI?

 

[dremu]

For example, I can't just install F.I. on my current engine. Legally, I have to install the newer engine/trans and retrofit any computer controlled devices, emissions related or not.

Mmm. I think if you have an EO # you're good. If you're going the junkyard route, of course, that's tough, but if you were thinking of, say, a Howell kit, you'd be golden as they have one that's CARB compliant.

And uses all GM TBI factory parts and just magically works.

-- A

 

[dyeager535]

CA's rules make sense (in a way) in that they are based on the design of the engine. Whoever wrote those laws was smart enough to realize that you can't just slap a fuel injection system together and have it run as it was OEM. This is why things like "computer friendly" cams are a scam. It may run ok, but it will NOT run optimally...these systems aren't capable enough to modify how they run under all conditions, and that will decrease performance and increase emissions. I'm no enviro-nazi when it comes to legality, but at least when they did this, they used some sort of logic.

Anyway...the '87 only ran long enough for me to steal parts off of it. It's pretty much apples to oranges...the TPI has a lot of stuff on it that probably helps it out over the TBI motor, so it's not a fair comparison. Looking at the factory numbers in the Camaro's where the TBI and TPI were offered the same year however, and the TPI is quite a bit more of a potent setup.

IMO, when left alone, in a truck, the TBI motors are pretty good, especially since they were all geared pretty well. The carbed 1/2 tons were pretty universally handicapped with bad gears, and 3.73's will make any motor look good compared to when it's trying to turn 3.08's.

Either setup is a huge improvement over a carb. LS is really the way to go, but in CA it probably brings a whole host of issues that you won't see with a TPI or TBI swap.

I still can't figure out why GM wasn't willing to put TPI in the trucks (well, it was probably $$, but they were too stupid to see that those $$ spent would have bought customers). TPI would probably have had people clamoring for the trucks at that time.

 

[My85]

dremu,
Thanks for the Howell link. I will have to research their EO#. If it is similar to Holly’s it’s only legal as direct replacement parts for an existing TBI system.

dyeager535,
Since my K5 already has VSS installed would I need to swap the dash if I use TPI?

TPI w/MAF sounds like the way to go IF it is legal to use a 700R4 in place of the stock turbo350. If not, TBI will still be an improvement over my current computer controlled carb.

Thanks again guys for your assistance.

 

[dyeager535]

MAF TPI is "junk", you want MAP. Look at the replacement MAF cost vs. MAP, plus intake tract difficulties in fitting MAF. Early MAF is even worse than later MAF. Can't recall all the years, but '85 you for sure want to stay away from, and in '88 or '89 they went to the "better" ECM which is better in terms of data output for tuning requirements. All MAP has the later ECM's, and are better supported now than MAF. MAP limits you to '90-92 F-bodies, and I *think* 90-91 Corvettes.

You don't have to replace the cluster, only if you went with a '90-91 harness, since those are wired for electronic speedometer (and the cluster wiring I believe is different in general) plus the wiring for the VSS. My personal opinion is that the '90-91 setup is inherently better, but that's another story. Simply for conversions sake the '87-89 setups would be slightly easier, but when I say VSS I am talking in regards to the '90-91 setups as they completely eliminated the speedometer cable.

All of the 87-91 C/K/R/V truck ECM/PCM's used the same VSS input, just different ways of getting that input to the computer.

 

[dremu]

dremu,
Thanks for the Howell link. I will have to research their EO#. If it is similar to Holly’s it’s only legal as direct replacement parts for an existing TBI system.

Their whole selling point was that it's as an upgrade, I thought.

OTOH, my truck is pre-smog so I have no first-hand experience with it.

-- A

 

[4X4HIGH]

MAF TPI is "junk", you want MAP. Look at the replacement MAF cost vs. MAP, plus intake tract difficulties in fitting MAF. Early MAF is even worse than later MAF. Can't recall all the years, but '85 you for sure want to stay away from, and in '88 or '89 they went to the "better" ECM which is better in terms of data output for tuning requirements. All MAP has the later ECM's, and are better supported now than MAF. MAP limits you to '90-92 F-bodies, and I *think* 90-91 Corvettes.

You don't have to replace the cluster, only if you went with a '90-91 harness, since those are wired for electronic speedometer (and the cluster wiring I believe is different in general) plus the wiring for the VSS. My personal opinion is that the '90-91 setup is inherently better, but that's another story. Simply for conversions sake the '87-89 setups would be slightly easier, but when I say VSS I am talking in regards to the '90-91 setups as they completely eliminated the speedometer cable.

All of the 87-91 C/K/R/V truck ECM/PCM's used the same VSS input, just different ways of getting that input to the computer.

You have it backwards, MAF TPI is superior over MAP TPI. Yes it is a little harder to fit a MAF sensor nicely and yes a MAF sensor does cost more than a MAP sensor but you can do ALOT more to the engine when running a MAF system.

 

[My85]

4x4 HIGH,
Thanks for your response.
Installing a TBI engine is the easiest since it was offered in K5s. I thought I had read somewhere that to use a newer engine the matching transmission had to also be used. Which raises the question of if I can legally install a TPI engine since if I'm not mistaken cars were running turbo350/400s and I really don't want to give up my 700r4.

 

[dyeager535]

You have it backwards, MAF TPI is superior over MAP TPI. Yes it is a little harder to fit a MAF sensor nicely and yes a MAF sensor does cost more than a MAP sensor but you can do ALOT more to the engine when running a MAF system.

How so? What can MAF do better than MAP, when talking GM OBD1? Edit: unfortunately I can't find a link that explains all I mean, but look at it this way, when talking GM OBD1 MAF vs. MAP. MAF ECM's (165) have a documented problem with datalogging. They are ALL buggy and shut off data flow at some random point. You have to shut down/restart the vehicle to get data out. All MAF systems but I think one year (1989) use the stupid 9th injector. Not only is this more complex, but the ECM is also outdated, and uses the same baud rate as TBI....160 vs 8192. So your resolution in tuning is worse. The resolution on timing is also worse: MAF uses a much smaller timing map with fewer data points...it's less accurate and uses more "assumptions" in timing since the gaps between RPM and load are greater. Finally, very few people are even messing with MAF anymore. The '730 ECM is better, it has more users, thus it's better supported.

MAF *may* win in the "bolt on and go" category, but if the engine is not stock, it still doesn't matter, fueling will be wrong. While MAF measures the airflow into the engine, it measures this through voltage changes. Those voltage changes are used to change fueling. If you change the volumetric efficiency of the engine (VE, so intake, cam, heads, exhaust, anything along those lines) the MAF calculations are wrong because volts vs. grams/second (what the MAF/ECM use as airflow measurement) no longer means what it does stock. A more efficient engine (all else equal) will flow more air at a lower RPM than a less efficient engine. Therefore, the engine will actually run lean until someone electronically goes into the PROM, and increases the MAF voltage to equate to the new airflow. IE what used to be 22 gms/sec at 1.46V now needs bumped up to 24gms/sec. Here is a shot from a tuning program showing the TPI MAF (1989 6E code) sensor tables http://s1271.photobucket.com/user/jamallhughes/media/ScreenShot004_zps1b8e82dc.png.html This difference in airflow vs. MAF calculation is not normally going to be "felt" when modifications are minor...the O2 sensor will adjust the fueling to compensate for the error in calculation coming from the MAF. But since the O2 sensor cannot measure or be used to adjust fuel under certain circumstances (starting the engine, idle in some cases, acceleration, hill climbing, towing, etc) the engine WILL run lean at those times. Depending on other factors, that may result in engine knock, retard of timing, and massively decreased performance. Worst case you may lead to excessive engine wear/destruction as the heat generated from running lean soaks the cylinder and all components.

It cannot be understated what a difference even the weight or gearing of the vehicle will make in how efficient the engine is. GM used a different PROM based on simply manual or auto trans. Gear ratios, you name it, if the drivetrain or base vehicle was different, the programming was different. You hear plenty of people who say they just bolted it on and it was fine. That may be a true statement. But working, and working as efficient and powerful as possible are two completely different animals. Dad couldn't tell when his TBI was running 20% lean as a for-instance, that was obviously costing power and dangerous though. At least on my TPI, improper fueling and/or timing for my engine modifications shows up immediately as knock counts, and you know whats going on simply by seat of the pants, and MAYBE a little ping or two.

From what I now understand, later MAF stuff (OBD2) is much better than what TPI was. Apparently TPI was designed around a digital MAF, but ended up with analog.

In regards to the 700R4 statement, most everything injected got a 700R4 that was car or 1/2 ton truck. Only exceptions I can think of are the TBI 4.3L G-bodies (maybe B-bodies?) and Buick GN, which used 200-4R's. There might be some real one offs (like the 70's Cadillac fuel injection) but thats not something to worry about lol.

All TPI cars (and that's just F-bodies and Corvettes) got the 700, or a manual.