GEN I Differences...?

[Dr.Evil]

Ok, I have been wondering for a long time now why my 90 is slower than my old 89. Isn't the motor and tranny exactly the same? Only thing I can think of is the weight issue (the 90 has ABS and a moon roof and th 89 didn't) but I don't think that would do it. I mean the 89 just wanted to GOOOO and wanted to smoke the tires all day if I let it. Dont get me wrong, the 90 is still quick, but is nothing like the 89. So far, I have changed the O2's, TPS, Reset the EEC, and added a CAI and it is still really far off. I am putting in a LPM soon so that will help it. So my question is, what is different about the 90 that would make it slower besides weight? I just dont think it is living up to potential. I have to change the 90 EEC with a 89 for some reason to use the LPM...maybe the 89 comp has something to do with it....? Please post your thoughts.
Thanks!

 

[Levand16]

Maybe it needs a 60K?... When I got the 60K done on my 94 ATX it ran much better and quickier

 

[ricksmol]

I believe '89s had a much lighter flywheel. Thus the RPM's came faster.
Rick

 

[edmontonsho]

The performance difference between a 90 and a 89 regarding the weight will be very very minimal. If you 90 is slower, it is because something on it needs fixing.

 

[qiksho]

How old is your timing belt? This can rob you of lots of power, as I found out with my 89. 120k and 12 years on the original.

You could also have a clogged cat, as I have heard this will also rob you.

my dads 92 has always been faster than either my 89, or 91+...so I don't think the weight issue has much to do with it.

 

[Dr.Evil]

Thanks for the ideas. Now is there any way to check the cats or the timing belt?
I wanted to get a light weight flywheel put in when I had it out to change the clutch, but had to borrow $ for the clutch so a new 300+ flywheel was out of the question.
Only thing that I know that needs fixin is the pan gasket as it is leaking. But besides that the codes give me an 11 so I lost...

 

[JaySHOguy]

Some cars are just quicker than others... My first '91 SHO felt about as quick as my '97 SHO....but my '89 feels like it will blow my '97 away.

Factory freaks boink

 

[89 black SHO mtx]

take a temp reading of the cats if one gets hotter than the other it could be stopping up. you could take it to your local exhaust shop and have them do a back pressure test on it . if that doesn't help it could be fuel injectors stopping up. the best place to dhave them cleaned in my opinion is the dealership they disconnect your fuel pump and run a cleaner thru it by itself!!!! also you could have an injector winding or coil winding going bad. the possibilities are endless but thats the best place to start

 

[91 SHOplus]

I second the suggestions of checking the timing and maybe cloged cats. Neither are likely to throw codes, yet they are both big-time power stealers.

 

[Freak SHO]

Everyone knows that '89s are the fastest... thumbs_u

Some just choose not to admit it... shrug

 

[Dr.Evil]

how do you check the timing on these? shrug

 

[JoeHoe_SHO]

I agree, 89s are the fastest. Not air bags, no ABS, 5spd/ I raced a 97 SHO by the way.... I smoked him in every aspect. They are a little more fast on the top end, thats it. There is about a second and a half difference in 0-60 times