Can the MAF on an '88 LB9 compensate for the LT1 cam in stock form, or will ECM tuning be required? I have searched but can not find a simple straight answer to this question.
I have the fresh engine on the stand, just waiting on gasket kit to arrive Wednesday to seal it up, so I have until then to source an LT1 cam if it will work without EPROM tuning. Engine currently has a stock LB9 auto roller cam, but would like to get maximum efficiency out of the engine for daily driver use. Already planning on complete polish of the plenum, runners, base, intake ports, port matching everything, and installing a set of Flowtech shorty headers, possibly wire in a heated 3-wire O2 sensor moved to the Y-pipe downstream of both banks.

 

The Lt1 cam is not that different from the stock L98/Lb9 5 speed cam. Slightly more lift on the Lt1 cam. So, no tuning should be required,but you need to find out if you have the cam for the AUTO or the 5 speed. Look at this link on stock cams.http://www.gmtips.com/3rd-degree/dox/tips/cams/cams.htm

 

As stated, current cam and ECM are for the LB9 auto, I.E. the "Peanut Cam". I assume this means the LT1 cam will be beyond the compensation abilities of the MAF with the stock ECM tune then?

 

no it will be fine. look up some of the tbi lt1 cam links and u will see.

 

actually,look up comp compucams and u will get an idea of what can be ran without issues

 

I played with some of theirs on the Compcams Camquest desktop dyno, but they don't have anything close enough to gauge the LT1 off of...Not to mention they aren't clear about what modifications are necessary. Half the threads I find on here say chip tuning is needed, half say it will run fine without. Unfortunately NONE of them differentiate between MAF and MAP setups. I know a MAF system is generally more forgiving of changes to the engine, but I don't want to go thru with the swap if it's going to negatively effect any part of the driveability for a modest gain in only one part of the powerband.

 

i told you to look up cams that are made for computer controlled cars. Crane makes some too. You can go to Summit racing and look. Generally most of them will have a duration less than 220/220@ .50. and of course your lift needs to below about .470 or so cause of the stock GM springs. You will probably gain about 20hp or so going from the peanut cam to an Lt1 cam.

 

I think I'm going to stick with the peanut cam, and just maximize my efficiency elsewhere in the engine and intake. I'm getting too much conflicting info on the LT1 cam the more I search, and even tho you are trying to help (And it is greatly appreciated, I assure you!), I'm not seeing anything that tells me that the '88 MAF LB9 computer in stock form can compensate for and properly feed the LT1 cam, at least not without badly effecting idle quality. If I see something that says the stock tune can adjust for the LT1 cam, and still maintain a proper idle and part-throttle operation, I will do the swap. But I don't want to take the risk and end up with a engine that bogs under idle or part-throttle conditions just to try to gain 20hp in the upper RPM range.

 

The LT1 cam will be fine.
Here is something to wrap your head around.
I have a 400 stroker with AFR 235s, mini ram and a solid roller with close to 700 lift and 250I-254E @ .050.
Right now I'm running a STOCK 89 formula 350 chip and 24LB injs. Drove it 6hrs 1 way, got 22mpg highway and idles at 550 rpm.
Stock chip. Yes It will be tuned as soon as I put in the 60lb injs after the break in but it ran with 0 hickups.. She always has been good to me..

 

Will I need to upgrade to larger injectors? I have access to many sets, many sizes, all flow tested. What flow range would I need?

Sorry for all the questions, I'm not used to leaving things in the hands of a stock ECM. My '83 Z28 is running a Megasquirt-I ECM (MAP setup) with a fully custom tune on a roller 327 TPI with an LT4 hot cam and 11:1 compression, with 36 lb/hr injectors. It's taken a while, and a lot of trial and error, but I've got it behaving well with a 700 rpm idle (with no idle air circuit) and 22 mpg. Factory tunes are anathema to me.

 

Should be ok with 19s and a lil fuel PSI bump.

 

u can always do 1.6 roller rockers. It will increase lift a little and give a little better sound.

 

So, the correct answer to my question is NO, the stock LB9 tuning will not work with an LT1 cam. If I'm having to adjust fuel pressure, then that would mean the MAF system does not have enough adjustment leeway within the stock tune to compensate for the LT1 cam. If you are talking about playing with fuel pressure, I would either need a wideband O2 or dyno tuning to ensure correct AFR at WOT, neither of which I am willing to invest in for the meager reported gains.
I am looking for a drop-in-and-go upgrade for a - STOCK - LB9 with automatic transmission ECM '88 IROC-Z. If the LB9 computer - can not - handle the LT1 cam, I am not going to waste the money or energy.

 

That's my next mod for my '83 Z28, going to go to 1.6 ratio full fulcrum roller tip rockers to get the max performance out of the LT4 Hot Cam. The holdup is the price tag between rockers that will fit centerbolt heads, and tall centerbolt valve covers that will give enough clearance. As such, not something I'm looking at investing in for the IROC-Z anytime soon, as it faces the same issues.

 

It will work. You are waaaaaay over thinking this. You said you were willing to change injs?? That really requires tuning. bumping to 50psi doesn't mean you need a dyno or tuning, the O2 adjusts afr a certain% no matter what psi you run.
If the maf system is running my 24s and my 55fuel psi... you will be fine.
The LT1 cam isnt anything to write home about, its freakin' mild.

 

The MAF should handle the LT1 cam just fine. I've tuned a 360" motor running a big 230 deg cam that ran ok on stock MAF tables. WOT was of, but idle and cruise were pretty close.

A stock LT1 cam should have no problem. Like said, its not much bigger than a L98 cam and some 305's got that cam. IF worse came to worse, find a 305 tpi chip that had a L98 cam. I dont think it will be necessary tho.

 

better not forget the springs!

 

Springs are already upgraded to the Hot Cam Kit spec springs (ordered from Scoggin-Dickey), and had the heads machined for them and the extra lift of the LT4 Hot Cam with 1.6 rockers (.525"). While the heads were off they got brand new valve stem seals, a valve job, port matching to my TPI base, and did a complete port / polish on my TPI system, including a polish of the exterior. The insides of my runners and base are glass smooth, the transitions are all port matched, I unshrouded the injectors, and I removed / rounded off all the restrictions in the upper plenum with port matching to the runners. The rockers are the last thing I'm waiting on, if I don't just end up saving for an LS conversion first. I'm starting to lean more and more that way on my '83...

As for the LB9 car, the whole goal is to keep it as close to stock as possible, kinda the opposite of my '83 where I said "SCREW STOCK!" and basically went with my crazier whims. It's a 95% RPO-correct car, and I'ld like to make it as original as possible. After using Megasquirt on my '83, custom EPROM burning just doesn't seem worth the hassle or expense. That is why I'm so keen to keep all the upgrades to it within the confines of the stock ECM's abilities. I do need to maximize the mpg it can get however so my wife won't complain when she starts driving it, and I can FINALLY pry the keys to my '83 back from her.

 

I agree with Orr that the WOT tables may be off a bit, which can be somewhat compensated for with fuel pressure adjustments and a wideband, but for CL operation it would be fine. Other than that the main issue would be the injector size, as you will need a tune if you want to step up from the 19s. Keep in mind that with a tune and your mild upgrades you could surely throw some timing at it to gain horsepower in the upper RPM ranges.

Don't be afraid of a wideband; they are simple to set up, and very valuable when it comes to the bottom line of monitoring the function of a tune. For example, the Innovate MTX is a very good value, as it is fully digital, comes with datalogging software, and only sets you back $200.

 

I plan on a wideband setup for my '83 eventually, which will allow autotuning with my Megasquirt. Unfortunately, that $200 price is also what is keeping me from having yet installed one.

Back to the LB9 / LT1 cam...WOT will suffer, with stock injectors and fuel pressure there will possibly be driveability issues...I think I've gotten the answer to my question.

 

WOT MAY suffer... I'm not 100% sure but that cam should be worth 20-25hp over a peanut easily, so it may need abit of fuel up top. Then again some of these cars run rich from the factory so the cam would lean it out just right. I'd try to find a chip for L98 cammed 305 or just buy the software and do it yourself Its cheap and easy to do. PCM for Less could give you a stock chip for 150 bucks or so. Thats another option.

If you told me the stock chip's bin file code, I could look that up and compare to other MAF LB9's with the different cams and see what the fuel tables look like.

 

About the only thing I can do is give you whatever identification markings are on the chip in the ECM.

I just really want to avoid the whole EPROM-burning fiasco I know it will turn out to be. I've had several years experience tweaking AFR tables with my '83 now, and I know how drawn out of a process it is to get the entire RPM range properly fed. I can't see chip burning being any easier, and especially don't see it as very economical, even if I build a burner myself. The problem is without reliable feedback on the tune, I'm still going entirely by ear and feel on the effectiveness of any changes. At least with Megasquirt I get real-time feedback via sensor readings, A/F ratio (narrowband but still datalogged and visualized), and can datalog and interpret the data later. With a chip it seems to be limited to "burn it, install it, hope it doesn't blow sh#t up".

And I stress yet again, my original question was will the LT1 cam work in the MAF LB9 WITHOUT modifications to the system. As much as you guys keep claiming it will, you are in the same breath telling me I need chip tuning, adjustable fuel pressure, larger injectors, timing changes, will have WOT issues...So, I put the question to you this way;

Will the LT1 cam work properly throughout all RPM ranges and throttle inputs with the stock MAF LB9 auto trans programming and fuel system, and not require ECM tuning or fuel system modification? Simple answer only, yes or no, which is it?

 

let me know the markings on the chip and I'll look to confirm programming settings.

In simple terms it will work with no changes. But its never a simple matter. Not all motors respond the same way to the same set of mods. IMO the LT1 cam on stock MAF system should have no problems if you run it with no changes to anything else. Just stock settings.

However there are somethings to be gained with some minor changes. Fuel pressure can be played with if you wanted to but its not necessary IMO. Its a small cam that isnt much bigger. Timing may make a big difference. Its all worth the effort to try to get the most out of it. It doesnt have to be done, and in short, yes it will work with no changes...but some helpful suggestions were made to improve the swap effort.

I havent done that cam swap but I do know for a fact that stock programming on L98s can be used with different intake manifolds which greatly change the powerband and fueling was ok still. More was gained in tuning but it ran fine as is no other changes. MAF does well in MOST applications as long as you dont max out the MAF sensor flow limit.

Do the peanut cammed cars come with the same valvesprings as the L98 cam cars? If so the LT1 cam will work ok with 1.5 rockers only.

 

If not I have the valve springs from my 350 4-bolt truck heads I can use, and a set pulled from 906 casting Vortec heads. I believe they are all the same spring, but I will research before I do anything. I'm leaning back towards the LT1 cam, especially after showing my friend this thread and letting him read thru everything. He also points out that the port / polish on the intake may make the peanut cam more on the lean side due to better airflow, even if it's just from freeing up restrictions and turbulence within the system. Either way, I always prefer to do my homework before jumping into anything, it saves money and me from banging my head against the wall later.

 

Facts
1. The MAF system is more forgiving for changes to the engine.
2. The bump in fuel pressure is to increase the available fuel for the extra power
the LT1 cam will make. Check out: http://www.dynamicefi.com/TBI_Fueling.php

This will help you understand the relation between fuel pressure and sustainable power.
3. Tuning the ecm will get you the best power, just like tuning a carb will.
4. A carb you just bought will make your car run with some minor tweaks, but intensive tuning will be required to eek out every last pony. The same applies to the MAF set up. The only difference is that the MAF does the tuning for you.

Hopefully that answers your questions and lays your fears to rest. The LT1 cam will work with the MAF setup just fine. That's my

 

Agreed the lt1 cam will work fine no need for larger injectors. You could data log and adjust lv8 but it will work fine as is. Maybe even goto $6E .bin

 

LT1 cam will run great in a MAF TPI 305. It also works great in TBI 350 truck engines on the stock tune.

 

For what its worth, I'm running an LT1 cam in my LB9 with 22lb injectors and the injector constant changed in the otherwise stock .bin. The engine runs strong with this cam and I haven't had any driveability issues.