lduley

iTrader: (1)

I'm sure these have been discussed before, but I'm not having luck searching, possibly because I'm not sure how to word the searches.

First off, I have a 88 coupe, N/a that I hurt body wise. I know nothing about the motor of the car except that is has supposed to of been rebuilt at one point. I have no idea what was done to the motor, but I believe that is WAS rebuilt because the 5th/6th port actuators are gone, along with the air pump, and it has a ACV block off plate. Also has stock exhaust manifold connected to 2.5" pipe going back into magnaflows, no cat in the system. Granted these are bad things to go off of for thinking its a rebuilt engine, but its all I have to go off of.

Now, today I drove a 88 GXL to possibly buy to replace the 88 coupe. It is BONE stock, unmolested, 93K miles. But, I noticed that it had NO where near the power my 88 coupe had, which concerns me, but not sure if it should be a concern. Honestly between the 2 it feels like a 100 horse difference (I know it isn't, but thats what it feels like)

Now, here are my questions, would the removal of the Air pump, actuators, and addition of the 2.5" exhaust make THAT much of a difference? I wouldn't think they would, but I guess anything is possible.

2: Are there major visual differences between a turbo trans and n/a trans? Same with the differential? I am curious to get under my coupe and see if maybe a turbo drivetrain swap has been done, knowing that could be why my coupe feels faster.

3. Is there a way I can tell if I have a S5 keg versus a S4 in my coupe?

now I don't know the health of the GXL, I have not done a compression test to it yet, only drove it, but it fires right up cold, temp gauge comes up normal (1/4ish mark) and restarts hot with minimal effort of the starter. Same goes for my coupe, BUT I know that at least the front rotor, last I checked it, has 90 PSI on all 3 faces, which I know isn't spectacular, but to me it would seem that the GXL and my coupe should feel as if the acceleration is the same, at LEAST somewhat comparable, that is if the compression #'s are close to being the same.

I understand most of my questions are vague, but any input would be appreciated.

Also when it come to the differences between the trans and differential, if pictures are available, will make things MUCH easier to me

misterstyx69

iTrader: (142)

the TII trans has a separate bell housing where the NA does not..easy tell.

S5 keg vs s4..water pump thermo neck on s5 has 3 bolts,S4 has 2.
s4 omp is mechanical,s5 is electronic.
the spark plug holes are offset on the s5..(something like that.)

lduley

iTrader: (1)

Ok so the one in my coupe is a s4 for sure. Now i just gotta get under it after work, cause the power difference is bugging me. Is a s5 LIM designed the same as a s4 except the actuator holes are covered? Thats how mine is, but they are covered up extremly smooth, doesn't look like a jbweld job by any means

clokker

iTrader: (2)

The T2 transmission and diff are stronger and the diff is LSD (most NAs are open) but neither actually increase the power.
Gearing differences in the diff may make one car accelerate quicker but ultimately, it wouldn't be faster.

lduley

iTrader: (1)

Thats why i said it "felt" more powerful, but different gear ratios would make it feel like that too especially if its getting up faster. Is there a visial difference in the differentials? Or will i have to jack up the back and turn the driveshaft?

clokker

iTrader: (2)

The T2 diff has more ribs cast into the rear cover.
I'm thinking either seven or eight, but could easily be wrong.
There's usually a tag on the fill plug saying it's a LSD but that can disappear over time, so don't count on it.

j9fd3s

iTrader: (3)

the T2 trans is really easy to spot, it has a removable bellhousing and a removable flat pan on the bottom.

the S4 vs S5 engines are a little tricky, as you can mix and match a lot of stuff. if there are threaded holes right above the spark plugs, the rotor housings are S5. if your center iron has an EGR valve on the top of it, its an S4. on the rear iron there is a flat plate on top, by the oil filter, if there are two bolts for this, its an S4, and if its one bolt its an S5. the front irons are virtually the same.

for power there are a bunch of things that can/might be going on.

the GXL might have 6 ports that are stuck shut.

the exhaust also makes a huge difference on these cars, so your exhaust is adding power, and who knows what kind of shape a stock exhaust is in, its a quarter century old

lduley

iTrader: (1)

Well its a n/a tranny, open diff from what i can tell too. So now i'm very curious what was done internally of the motor in the coupe. Guess when i yank the motor i'll find out

RotaryEvolution

iTrader: (30)

the gxl is probably just lacking in functionality/maintenance, if the auxiliary ports are stuck then it is going to feel like a sick dog when it should be making power in the upper range.

basic tune ups usually result in waking up a car:

check and adjust the TPS, replace it if it fails the sweep test
replace spark plugs if they have over 15k on them
check plug wires and their firing order
be sure leading ignition is actually firing
replace the fuel filter
check and adjust timing to default
check the 5/6th actuators to be sure they aren't stuck
check the catalytic converters for fouling, the power loss can be night and day
check the air filter and replace it if it's dirty
check for vacuum leaks, any leaks will result in a power loss

even only one or two of those things out of order will cause major power losses.

lduley

iTrader: (1)

Extremely good chances on all those accounts. I will probably get it for sure and it'll be a little winter project....even though the heater works awesome in it, heat in my truck stinks