Texas GN

[Glen Crisp]

Jack, just bought a 1987 25k GN that has been in a warehouse for many years here in San Antonio Tx. The car has had a few mods on it but i think for the most part it is stock. The mods are dual exhaust 2.25 ,headers, gauges (boost,temp,oil pressure,temp) hypertech chip (PT# 41 373). Can't seam to find any info on a 41 373 but there is plenty of info on the 41 372. I changed the gas tank out because it was full of rust and changed the fuel pump to a Walbro 255lph.
Oh, one other thing I have a hot wire kit for it too. I noticed it is running lean, the plugs were very clean; to clean even after 500 miles. Anyways I would like to get the car into the hi 12s low 13s. I need you to put me on the right track, you said something about 42lb injectors and a chip? Can i use the chip i have? Are the Valve springs up to the tasks? I hear they were weak too. Thank again, Glen

[Mike_g]

Sounds like A BEAUTY.. I didnt see anything about the fuel filter being changed out. You should definatly do it If you havent already.
You will need a chip for the #42 inj Im sure Jack has some in stock
Good luck
Mike
Post up some pics :) !

[Glen Crisp]

Thanks, I was planning on ordering the injectors asap but what about the Hypertech chip? Should I scrap the one that's in there now? Or should I try it with your 42 lb injectors?

Thanks Glen

[Mike_g]

Hi Glen,
Your going to need a new chip for larger injectors. Chips have come a looong way since that hypertech chip. It was most likely intended for use with stock injectors.
Chips now a days are burnt specificly for the injectors. Should you go to a larger injector after the #42s say maybe #50s same rule will apply
Hope this helps

[waGoN]

Yup, Mikey is right.
First thing is work on the fuel system, which you have already started. I agree with Mikey, replace the fuel filter if you haven't. Does it have an adjustable fuel pressure regulator? All chips burned for this car require that the fuel pressure be set a bit higher than the factory non-adjustable unit is set for. Factory is 30#, I think, and most chips want you to set it for 42-ish.
Make sure everything is running right, FIRST. Then injectors and a chip. And as said, chips are programmed based on injector size. After that, if you want more go, then turbo, and/or a higher stall converter. Oh, don't forget, you are going to need to put tires in your budget.

[Glen Crisp]

Here's my car! 1987 Buick Grand National, 25k miles, just needs a little kick!

[Glen Crisp]

Thanks Guys, Starting to feel better about this project. I did change the fuel filter first thing when I pulled it out of the warehouse. That’s how I discovered the tank was shot. One thing I did not think about was a new regulator. Is there a replacement for the original position or just mount a Holley underneath somewhere. (Is there a recommended part number from Cotton's) Back to the fuel injectors, is the 42lb best ones for a stock block and turbo? Or can I just skip the 42s and move on to the 50s like previously discussed.

Thanks again for your assistance!
Glen

[waGoN]

Give Jack a call, and he'll set you up with a good regulator that mounts in the factory location. As for injectors, the biggest that you can go without modifying the computer is 60#-ers. (Actually, I think they may have something a little bigger. Not sure.)
The chips for the 60s are supposed to be pretty good for anything from mild to wild, so I would recommend going with those and a chip to match. You don't want to buy a chip for 42s, then upgrade injectors, and have to buy another chip, then upgrade injectors again to 60s, and have to buy another chip. Go as big as you can. It will be good for what you have now, and will be ready for future upgrades.
Just to be sure, talk to Jack about what you have, what you want now, and what your plans are for the future. Just remember this. When I built my toy, I started out saying I only wanted to put it into the 12s, and I'd be happy with that. Then, I just wanted low 12s. Then once I got a low 12, I just wanted an 11.................well, now I am getting a motor that should blow right past the 10s and put my waGoN in the 9s. So, keep that in mind. Most people don't stop with one little upgrade.

[Mike_g]

Remember that line.. If I knew now what I didnt know then.
I personally would go # 50s. You could easliy hit 13s/12s with stock injectors. Although from what you told us there could be some fueling issues. Replacing the injectors may be wise. The boost reg would be on the fuel rail
When the boost bug bites you will have plenty of room to grow

[Mike_g]

Too funny Brian beat me to the punch ..:D

[Glen Crisp]

Alright guys, I am taking you advice! I called Cotton’s and Jerry put me on some 60lb injectors with a chip. He said it should work well with my present setup. (I caught myself looking at turbos on their website too!) My wife is gonna kill me! Anyways, I found a Holley regulator # 512-503-5 (35-65psi) this should work with that setup right?

Thanks again, Glen

[JCotton1]

Alright guys, I am taking you advice! I called Cotton’s and Jerry put me on some 60lb injectors with a chip. He said it should work well with my present setup. (I caught myself looking at turbos on their website too!) My wife is gonna kill me! Anyways, I found a Holley regulator # 512-503-5 (35-65psi) this should work with that setup right?

Thanks again, Glen

Hi Glen, welcome. I see my boys have been talkin for me, they're the best!!! Thanks Guys. I would recommend you get the Accufab reg we carry for your car. It's the best out there... with that.. got to run...
thanks so much,

[Mike_g]

Alright guys, I am taking you advice! I called Cotton’s and Jerry put me on some 60lb injectors with a chip. He said it should work well with my present setup. (I caught myself looking at turbos on their website too!) My wife is gonna kill me! Anyways, I found a Holley regulator # 512-503-5 (35-65psi) this should work with that setup right?

Thanks again, Glen

The holley should work.. Unless you found a good price on the holley
The Accufab Is much better + you already got an Order going w/Cottons. Best bet save yourself some shipping cost have em add it in

[Glen Crisp]

Ok, Guys….The BIG Question! .... with the mods the car has now ( Magna Flow 2 ¼ exhaust, headers, hot wire, Walbro 255lph fuel pump, 60lbs injectors, regulator and a custom chip) what should I expect down the quarter mile? Any guesses? Oh Yes, I realize I gonna need some wide rubber too. Jerry was telling me there is a nut on the waste gate for adjusting boost. Can you recommend a safe boost level; I have seen it as high as 17psi now. Will I need to back that off or crank it up some?

[Mike_g]

Do you have a scan tool... Scanmaster ? You really cant turn it up without monitoring it

[Glen Crisp]

It sure didn’t take long for ya to find something else I need!!!! I will have to sit down this weekend and read about them.

Thanks

[Mike_g]

Sorry here's some good info to check out http://www.gnttype.org/techarea/sunday.html
http://www.gnttype.org/maint/basics.html

[Glen Crisp]

Thanks, great info. I guess i will pull the intercooler next and clean it too.

[Glen Crisp]

Hey Guys, one more question if you have time. I have been reading about the factory valve springs on the GN. What some sources are saying is that the valve springs are only 80 lbs new and more like 60-70 worn. They are recommending that they are changed to a mid 90’s LT1 (110lb) spring. Is this something that you would recommend with your recipe? Or is this just a waste of money and time on a low mileage GN. Thank again for your input.

Glen

[Mike_g]

To be honest Im on the fence with that one.. In one apsect Even though the car is low miles. Its 23 years old and thats a long time to be compressed. Especially If it has sat in one place without being started on a regular basis.
Ok I take it back .. I think its a good Idea to replace em

[waGoN]

Yes, but make sure you add the oil additive that has zinc in it. (ZDDP plus, or something like) that. The oil made nowadays doesn't have the zinc in it that it used to, and it has caused some problems with non-roller cams. AND, the Buick has had problems with these 3.8 blocks also. Those two, coupled with stronger valve springs might do your cam in.
Most people have said that the factory cam doesn't have problems, but why take chances? Oh, and if you go with a new cam, I highly recommend going roller. It is worth the extra couple of bucks.

[Glen Crisp]

Hi Glen, welcome. I see my boys have been talkin for me, they're the best!!! Thanks Guys. I would recommend you get the Accufab reg we carry for your car. It's the best out there... with that.. got to run...
thanks so much,

Hey Jack, just wondering if everything got shipped out like you expected this week? Could you please let me know when I should expect delivery?

Thanks, Glen

[JCotton1]

Hey Jack, just wondering if everything got shipped out like you expected this week? Could you please let me know when I should expect delivery?

Thanks, Glen

Yes Glen, shipped out, I just checked the tracking, delivery is scheduled for tomorrow. Very sorry about the delays, seems we been slammed lately, but we are back on top!!

thanks much...

[Glen Crisp]

Yes, but make sure you add the oil additive that has zinc in it. (ZDDP plus, or something like) that. The oil made nowadays doesn't have the zinc in it that it used to, and it has caused some problems with non-roller cams. AND, the Buick has had problems with these 3.8 blocks also. Those two, coupled with stronger valve springs might do your cam in.
Most people have said that the factory cam doesn't have problems, but why take chances? Oh, and if you go with a new cam, I highly recommend going roller. It is worth the extra couple of bucks.

I will try and stay out of the engine until I have no choice. I just finished going through my 67 camaro’s small block and it was kind of pricey. Anyways it sounds like the Turbo upgrade is the best bang for the buck. Can you guy’s recommend one of Cotton’s Turbos for my semi stock application? I don’t have a problem changing out the torque converter for a little more stall if it is necessary.

Thanks Glen

[Glen Crisp]

Yes Glen, shipped out, I just checked the tracking, delivery is scheduled for tomorrow. Very sorry about the delays, seems we been slammed lately, but we are back on top!!

thanks much...

Thanks. i will keep a look out for it!

[Glen Crisp]

Yes Glen, shipped out, I just checked the tracking, delivery is scheduled for tomorrow. Very sorry about the delays, seems we been slammed lately, but we are back on top!!

thanks much...

Hey Jack, got the regulator and the injectors but no chip. Could you please check on it? Was it coming from your address? Thanks Glen

[waGoN]

I believe Jack is in Oklahoma this weekend tuning on some cars. Your best bet would be to call the shop if you have an issue with an order. He may not have internet access. I think he'll be back on Monday, but a call works best.

[Glen Crisp]

Thanks, I will do that!

[Glen Crisp]

Hey Jack, Got the chip and installed the regulator and injectors. Anyways I set the pressure at 43psi on the fuel rail and went through the setup per the instructions. The car runs better at idle but I am only getting 13-14 psi of boost at WOT. Any ideas?

Thanks again, Glen

[BrianHynes]

Hey Jack, Got the chip and installed the regulator and injectors. Anyways I set the pressure at 43psi on the fuel rail and went through the setup per the instructions. The car runs better at idle but I am only getting 13-14 psi of boost at WOT. Any ideas?

Thanks again, Glen

Glenn, assuming your boost gauge is working properly, you might want to check for any exhaust leaks ahead of the turbo. Cracked headers are common with these cars, and often don't show themselves ( noise wise ) @ idle. Look at all weld joints where the primaries meet the main log. I like to start the engine cold and quickly feel around these areas for exhaust pressure. If everything is fine, you should look at the wastegate. The spring could be weak from age, or the diaphram could be torn and not be keeping proper pressure on the wastegate puck. Then there is the boost solenoid ect--------but start with exhaust leaks first. Brian

[JCotton1]

Hey Jack, Got the chip and installed the regulator and injectors. Anyways I set the pressure at 43psi on the fuel rail and went through the setup per the instructions. The car runs better at idle but I am only getting 13-14 psi of boost at WOT. Any ideas?

Thanks again, Glen

What did you have before the install? Also, what do you use for boost control? Sounds about right for boost level, unless you run race fuel or alky injection.

[Glen Crisp]

You are right about the cracks; I welded the header up the day after I bought the car and I am fairly sure that there are no more leaks. The funny thing about it is when I had the Hypertech chip in there I was seeing 17-18 lbs of boost. I was thinking of putting the old chip back in it and trying it with the new injectors. If I get my boost back then you would think it would be chip related…right?

[JCotton1]

You are right about the cracks; I welded the header up the day after I bought the car and I am fairly sure that there are no more leaks. The funny thing about it is when I had the Hypertech chip in there I was seeing 17-18 lbs of boost. I was thinking of putting the old chip back in it and trying it with the new injectors. If I get my boost back then you would think it would be chip related…right?

No, the chip goes with the injectors. The chip controls the stock boost solenoid duty cycle. We typically use a manual boost controller to control boost. Do you have a means of adjusting your boost?

[Glen Crisp]

I don’t believe so. I there another way to check the boost solenoid and or adjust?

[Glen Crisp]

Thanks for all of your help guys, I adjusted the waste gate as instructed and it is boosting to 15-16 psi now. It took four turns to get there. I am assuming my target is 17psi for my max boost level (that was identified on the chip). The spring on the waste gate is getting good and tight now too. I have the fuel pressure set at 48psi on the 60lb injectors with the vacuum off as well. Hope that is close to what i need. I will aslo take a look at your manual boost controller today too!

[Glen Crisp]

Can you guys recommend which ScanMaster is the best for my application?

[JCotton1]

Can you guys recommend which ScanMaster is the best for my application?

There is only one unit called the Scanmaster. It is what we use and sell most often. Give Gerry a call, we should have them..
thanks,

[Glen Crisp]

I thought there were several versions of it. Scanmaster, Scanmaster 2.1 and the Scanmaster 3. I was wondering which one would be the best for me. Straighten be out if I am wrong! Thanks

[JCotton1]

Those are basically the upgraded units over the years. They all do basically the same thing, the higher the number the newer the unit.