School me on my 'Burban. Please...

[fixmy59bug]

Ok, Not too long ago I picked up an 89 GMC Suburban 1500 for the price of $650. This thing was in IMMACULATE shape so I could not pass it up. I bought it only to use as a tow rig since we just found out that the mustang + the weight of the trailer outweighed the old tow rig (My dads 85 Ford F150 4x4) by almost 1500 pounds. Anyways, Off topic, I have been a small car guy all my life. So when it comes to these trucks I'm not too knowledgeable. Of course I do have alot of automotive knowledge so I know the basics.

I know it has a 350 TBI with Auto overdrive (Which one? I don't know). Ohh yeah, I should probably mention it is only 2 wheel drive. No snow here in So Cal, no off roading for me so 4x4 is not necessary. However I had a 73 C20 (also 2wd) that I popped the trans on towing. That is why I bought the 89 (the whole burb was cheaper than the trans, why not.....) But I didn't want to chance my life, my dads and moms life, or anyone elses on the road, so I took the larger brakes (and whole suspension of course) and transplanted it under the 89. With the Hummer H2's under there, it is a good looking little rig. But here's what I am looking for as far as schooling:

First of all, What trans do I have? It is the stock trans from the 89, that was not changed. TH400, 700R4, 4L60, 4L80, 4L80E?? I don't know how to find out.

Second, I do know the 73 had (now the 89 has) a 14 bolt FF rearend. That thing is beefy, but I took it in for a Diff fluid drain and refill and they told me it has alot of sludge. They said I should make my drive this weekend with no problem, but after my trip I should bring it in for a full cleaning. True, Untrue, Something to worry about? Also, What gears do I have? And finally, Is it a Limited Slip or open?

Third, Are there any performance enhancers I should consider (please keep in mind that I live in Ca so I must get the truck smogged every 2 years and don't really want to have to remove headers then reinstall them) that won't break the bank? I am talking MAYBE having a budget of $200 per month to upgrade this (or my Vw) and I am bad about saving. So please don't say "Ohh you should save for 6 months and buy xxxxxxxxxx" It won't happen. I am not looking for enough power to pull the mustang on the trailer through glamis dunes or anything, but just something to make it less sluggish on acceleration). Sound would be good too. And hopefully it won't hurt the mileage too much.

So with all that in mind, Tell me what you can, tell me what you want, kick me out of the family (please, not really).

Thanks alot.

 

[BigEasy]

Ok, Not too long ago I picked up an 89 GMC Suburban 1500 for the price of $650. This thing was in IMMACULATE shape so I could not pass it up. I bought it only to use as a tow rig since we just found out that the mustang + the weight of the trailer outweighed the old tow rig (My dads 85 Ford F150 4x4) by almost 1500 pounds. Anyways, Off topic, I have been a small car guy all my life. So when it comes to these trucks I'm not too knowledgeable. Of course I do have alot of automotive knowledge so I know the basics.

I know it has a 350 TBI with Auto overdrive (Which one? I don't know). Ohh yeah, I should probably mention it is only 2 wheel drive. No snow here in So Cal, no off roading for me so 4x4 is not necessary. However I had a 73 C20 (also 2wd) that I popped the trans on towing. That is why I bought the 89 (the whole burb was cheaper than the trans, why not.....) But I didn't want to chance my life, my dads and moms life, or anyone elses on the road, so I took the larger brakes (and whole suspension of course) and transplanted it under the 89. With the Hummer H2's under there, it is a good looking little rig. But here's what I am looking for as far as schooling:

First of all, What trans do I have? It is the stock trans from the 89, that was not changed. TH400, 700R4, 4L60, 4L80, 4L80E?? I don't know how to find out.

Second, I do know the 73 had (now the 89 has) a 14 bolt FF rearend. That thing is beefy, but I took it in for a Diff fluid drain and refill and they told me it has alot of sludge. They said I should make my drive this weekend with no problem, but after my trip I should bring it in for a full cleaning. True, Untrue, Something to worry about? Also, What gears do I have? And finally, Is it a Limited Slip or open?

Third, Are there any performance enhancers I should consider (please keep in mind that I live in Ca so I must get the truck smogged every 2 years and don't really want to have to remove headers then reinstall them) that won't break the bank? I am talking MAYBE having a budget of $200 per month to upgrade this (or my Vw) and I am bad about saving. So please don't say "Ohh you should save for 6 months and buy xxxxxxxxxx" It won't happen. I am not looking for enough power to pull the mustang on the trailer through glamis dunes or anything, but just something to make it less sluggish on acceleration). Sound would be good too. And hopefully it won't hurt the mileage too much.

So with all that in mind, Tell me what you can, tell me what you want, kick me out of the family (please, not really).

Thanks alot.

Tranny should be the 700R4 4 speed auto. If it's never been rebuilt, look into a shift kit ASAP. The stock 700R4's aren't known for longevity, especially when used for towing. Sludge is bad, usually from dirt and/or water getting into the diff. Mechanic may or may not be lying, wouldn't hurt to get the rear end flushed & filled with new fluid if you've never had it done to that rearend. Gears you will have to remove the diff cover and count the teeth on the ring & pinion (# of ring teeth divided by # of pinion teeth = gear ratio). Exhaust (I prefer Flowmaster) from cat back would be the first power mod I would make. Then a high-flow air intake & throttle body spacer, then smog legal chip & thermostat. Doug Thorley make some sweet smog legal headers, but they run about $500 or so last time I checked. Good luck.

 

[Can Can]

Yeah, it's probably a 700r4. Just so you know, AVOID TOWING IN OVERDRIVE AT ALL COSTS. Additionally, spend the money on a quality stacked plate auxilliary tranny cooler- 700r4s hate heat. Trust me on this, brother.

Regarding the rear end, swapping out the fluid is an easy DIY job. It takes about half an hour, costs less than $20, and gives you an opportunity to take a look at what's going on inside the diff. This topic has discussed lots here at CK5, and if you spend a few minutes searching I'm sure you'll come across a few posts that describe the job step by step. I know, because I've posted in several of those threads.

Now, does your truck still have an RPO sticker in the glovebox? This build sheet gives all the codes that will help you figure out how your truck was equipped from the factory. The gearing codes usually start with a "G"- to help you decipher the codes, here is a link to a site that has them all alphabetized:

http://www.nastyz28.com/gm-rpo-codes/

Performance-wise, you're a little limited because you're in Cali. Every mod you do has to meet CARB requirements, and IMHO the little you will gain from most of the add-ons isn't worth the cost. Your best bet is to make sure the motor is well-tuned and well-maintained. If you want real power, you're looking at some pretty costly upgrades, especially if you can't do the work yourself.

That's about all I have to offer. Good luck, my friend!!!

 

[BigEasy]

Additionally, spend the money on a quality stacked plate auxilliary tranny cooler- 700r4s hate heat.

Now, does your truck still have an RPO sticker in the glovebox? This build sheet gives all the codes that will help you figure out how your truck was equipped from the factory. The gearing codes usually start with a "G"- to help you decipher the codes, here is a link to a site that has them all alphabetized:

http://www.nastyz28.com/gm-rpo-codes/

Good idea on the tranny cooler. However, he said he swapped the rear end out of a '73, so the 'burbs RPO gear code is useless. And I'll have to disagree on the performance mods. The exhaust, cold air intake, TBI spacer, thermostat, & chip (all smog legal) could all be had for about $600. It will improve the horsepower, torque, and mileage (if he can keep his foot out of it). The best part is, all those things can be done piece by piece, which is exactly what he's after...

 

[Can Can]

Yeah, it may improve a little, but not $600 worth, in my opinion. Everything you listed looks like about a 20-40 HP gain max. By rights, the 350 is a little underpowered for what he's using it for, and even with all the mods you listed, there won't be a huge difference in towing performance. Remember, I'm assuming he's towing at least 5000 lbs.........

If he went with a complete cam, intake and exhaust swap, maybe. But then there would be TBI tuning issues to take care of. And I'm still wary of the claims made my manufacturers of MOST of the TBI-related mods, anyhow.

 

[SUBFAN]

An '89 1500 series 'Burb will have under rated 15" tires. I would look into upgrading to some 16 inchers and tires with a better load rating.

The bigger trans. cooler is a must.

A free flowing exhaust (don't forget the cat.) and the right gear ratio would be my first areas to check out. I would shoot for 4.10 - 4.56 rear gears to help out in the towing dept.

 

[BigEasy]

Yeah, it may improve a little, but not $600 worth, in my opinion. Everything you listed looks like about a 20-40 HP gain max. By rights, the 350 is a little underpowered for what he's using it for, and even with all the mods you listed, there won't be a huge difference in towing performance. Remember, I'm assuming he's towing at least 5000 lbs.........

If he went with a complete cam, intake and exhaust swap, maybe. But then there would be TBI tuning issues to take care of. And I'm still wary of the claims made my manufacturers of MOST of the TBI-related mods, anyhow.

Well, I guess everyone has their own opinion on the bolt-ons... If we wanted to really pick apart best-bang-for-your-buck, he could install nitrous, but we all know that's not practical. I like the exhaust/air intake/TBI spacer/chip combo because even if they don't provide 100+ horsepower at the rear wheels, the improvement in driveability is definitely noticeable. As for cam/intake/exhaust, I installed an Edelbrock intake, a Comp Cams rv cam, and flowmaster exhaust with a high-flow cat on my '89 big block. All smog legal, no tuning issues at all, and good power gains (especially towing).

 

[k204dr]

this thread needs pics! sounds like a cool looking burb. What was the question again? oh yea, what about getting a better exhaust? the best thing though is to make sure its all tuned up, and the air and fuel filters are clean.

 

[79BRUISER]

As the owner of an 89 z71 with the 700 r4, I absolutly agree with the tranny cooler suggestion. 3 rebuilds and 2400$ can attest to the need for one.

 

[4xcrazy]

Someone mentioned something about a cold air intake mod to these, just had to chime in real quick and say if it's still stock under the hood, they are already equipped from the factory with a cold air intake system.

The hose from the air cleaner mounts to the air box on the radiator support and pulls air from in front of the support.

and yes, TRANS COOLER,,,NOW, it will help with making it last alittle longer,,,notice i said "alittle"

 

[fixmy59bug]

Ok. This has all been helpful to me. I had to print the whole thread so I can make sure I address all questions and pointers, LOL.

First and foremost, it seems the tranny cooler is the most mentioned item here. So that will be first on my list of "To Do's". The first thing that was mentioned was a shift kit. My boss (who previously worked for GM for 10 years) said if the trans has not been rebuilt, do not do a fluid exchange on it because the new fluid will create pressure and possibly blow out seals. But if I install a shift kit, I know I will be basically doing a fluid exchange. Not knowing how many miles are on this trans (odo reads 49K but only has a 5 digit odo), is it still safe to do a shift kit?

I am also starting to look into throttle body spacers, free-er flowing exhaust, and a chip. A thermostat is a cakewalk. I do know how to work on cars, but the lack of space to do the work is my only problem. I have helped my dad transplant a SB 350 into a 78 Chevy Luv, Rebuild his Ford's 351, and build up his Mustang's 428 SCJ to put out approx 500 RWHP. So I know my way aroudn working on these engines and vehicles, but not upgrading them. AS I said, Give me a small Vw, and I can go to town.

SubFan, I have already upgraded the tires. In my original post I said I transplanted the 73 suspension under the 89 and slapped on a set of Hummer H2 Wheels. That brings up another issue. I have got to install the 3" body lift kit I bought. This weekend I tore a couple lugs off the tires. Luckily it didn't damage the tires other than that.

I may also look into the intake and RV cam. Are those worthwile upgrades?

K204DR. Since pics were requested by you, I will get pics up this weekend and show off the $650 'Burb. AS I said, I am quite proud of it.

4xcrazy, Yes. I know exactly what you mean about the sort of built in cold air intake. I was under the hood in blythe checking everything out and it still has the massive 3" or so tube going from the air filter housing to the radiator grille area. So I think that is cold air enough for me. I don't see how it will really benefit from a "real" cold air intake so to speak.

The last thing I will ask for now is this. I used about 3/4 of a tank to go 400 miles round trip. I believe it has the 35 gallon tank which equates to 26 1/4 gallons of gas used. And that equates to approx 15 1/4 miles per gallon. That is pretty good considering the size of the vehicle and the fact that it is riding on those massive tires, Right? Ohh yeah, keep in mind that I was not towing anything. Dad backed out at the last minute so I had the generator, cooler, spare tire just incase, and all my camping equipment in the back, and the back seat area (bottom cushions were removed for more room) was 1/2 full of fire wood. I know when the torque convertor lockup switch was on, it was at a nice low RPM and drove GREAT. I had absolutely no problems (except for the nail I got in the fairly new right front tire). I also found out that the tires were about 1/2 way deflated (25-30 psi instead of the recommended 50 psi) when I got to my destination. So the ride home was a little bit steadier since the tires were properly inflated.

P.S. I also learned just how badly I need to reinstall that front sway bar. LOL. Seriously scary ride at times with the wind.

Edit #1: I'm sorry, there are 2 other questions I had for this thread. Easiest one first. Are shorty headers worth it? I have seen shorty headers, block huggers, full race, etc. Which is the best option for the money (I have seen full headers from $89 on summit's website). Is there any benefit to the full length over shorty's?

And Finally (hopefully) Is there any CA SMOG LEGAL way to fully convert from the cross over tube and single exhaust to a true dual exhaust? If that means I would have to run 2 cats I wouldn't mind but I would like a true dual exhaust setup if possible. Thanks

 

[BigEasy]

The dual exhaust is a tricky situation. A friend of mine spent a buttload of money on his '76 K10 with Thorley headers & stainless duals all the way back through a high flow cat and a flowmaster on each side. The first time he got smog tested he took it to a local mechanics shop. They told him he needed a crossover (equalizer) pipe from one side to the other to make it legal. He went back to the muffler shop and spent more money having the crossover put on and then he passed the smog test. Two years later he had to go to a "test only" station and they said no way, absolutely not. Guy told him anything different from the factory set-up (forward of the muffler) is reason enough to fail the visual portion of a smog test. He called DMV headquarters in Sacramento and they said the test-only guy was right. Once again he went back to the muffler shop and shelled out more money to have a whole new factory style exhaust put on. Needless to say, he bitched about it for quite some time. And one last thing, you can also get a ticket for modified exhaust here in CA.

 

[fixmy59bug]

Yeah, I wasnt sure how soon I could expect a response from this board so I made some phone calls today. I started with a local smog shop. Of course they referred me to the Referee. They had no clue (kinda sad that a smog referee doesn't know if it would be legal or not) so they directed me to the BAR. After some more running around I have found out from someone who told me most definatively that it would not be smog legal. He seemed fairly knowledgable about GM products as well from some of the stuff he was saying.

It seems the only way I will be able to do a "dual" exhaust and still have it smog legal is to put smog legal headers, combined into one single OE exempt high flow then split it after that. He also mentioned that the BAR is only concerned with what happens at or before the cat. He told me it could be straight open after the cat as far as they cared. But Johnny Law would have other words for me.

I learned on another forum that I frequent that the Db limit is either 92 or 95 Db's. However the officer can issue a ticket if he personally feels it is too loud. It is then up to me to get it certified and take that certification to court to get it dismissed. It seems to be total BS if he can issue a ticket if he thinks without having proof. But if that happens, you better believe I will fight it.

So that brings up another question. Is this faux dual exhaust worth it?

 

[4X4HIGH]

Let me start by giving you the least expensive mods. First is the injector pod spacer, next would be a K&N (drop in) filter, then the air flow enhancer, and finally an adjustable fuel pressure regulator and pressure gauge.

Headers and a SINGLE 3" exhaust with a hi-flo cat and free flowing muffler would make the biggest power increase but won't be cheap. Anything is better than a cast iron manifold and i hate long tube headers since they hang low and also you have an 02 sensor to worry about. I would run a pair of good shorty headers. If you decide on running long tube headers then prepare to install a heated 02 sensor otherwise chances are the engine won't go into closed loop operation.

California law on exhaust are as follows: If it came with factory single exhaust then it must have only 1 muffler. You can come off the engine with dual pipes and go into dual cats but those pipes must enter into the same muffler then you can go back to 2 tail pipes.

Gears make up for alot of towing grunt and depending on what size tire you're running will dictate what gearing you should run.