87 gn needs tuning, way slower than it should be

[justav6]

i have an 87 gn highly modified.last year it was running in the 12s and would neerly snap your neck. it was stolen in october and stripped bare. i finally got it back on the road and to the track. with my combo everyone says i should be in the 11s, but i just putted out a 14!!! its tough to tell by feel because while i was putting it back together i was using a corolla, so anything would feel fast now. my block is stroke bored .40 over, hypernetic pistons port polished stock heads and new mildly upgraded engine components. i have a stage 2 2004r trans with shift kit. turbonetics stage 3 t4 whith ceramic ball bearings, wide neck stock intercooler k&n air filter and oil cooler. flowmaster exaust, free flow cat, 3" poston downpipe. 42.5pph injectors, ?? fuel pump, external deltagate wastegate. new maf sensor, coil pack, etc. gta 16" aluminum wheels with crap tires. rear airbags, ram air kit, precision chip,im sure there is a lot more im forgetting. there is no one i know of that can tune a gn worth a damn in nj, all my current machanics are awful. i need someone to get it running like it should be. there were a few problems i know of that could have helped my 14. there is a large exaust leak from my elbow to downpipe which dumps exaust under my hood as well as melts everything. i know thats bad, but that cant be the only thing slowing me down so much. someone please help!!

[Hypsi87]

Originally Posted by justav6

i have an 87 gn highly modified.last year it was running in the 12s and would neerly snap your neck. it was stolen in october and stripped bare. i finally got it back on the road and to the track. with my combo everyone says i should be in the 11s, but i just putted out a 14!!! its tough to tell by feel because while i was putting it back together i was using a corolla, so anything would feel fast now. my block is stroke bored .40 over, hypernetic pistons port polished stock heads and new mildly upgraded engine components. i have a stage 2 2004r trans with shift kit. turbonetics stage 3 t4 whith ceramic ball bearings, wide neck stock intercooler k&n air filter and oil cooler. flowmaster exaust, free flow cat, 3" poston downpipe. 42.5pph injectors, ?? fuel pump, external deltagate wastegate. new maf sensor, coil pack, etc. gta 16" aluminum wheels with crap tires. rear airbags, ram air kit, precision chip,im sure there is a lot more im forgetting. there is no one i know of that can tune a gn worth a damn in nj, all my current machanics are awful. i need someone to get it running like it should be. there were a few problems i know of that could have helped my 14. there is a large exaust leak from my elbow to downpipe which dumps exaust under my hood as well as melts everything. i know thats bad, but that cant be the only thing slowing me down so much. someone please help!!

Do you have a scanmaster? What are your o2 milivolts?? Also how much boost are you running? Are you using race fuel or pump gas? Do you have alcohol injection? I need to know more of this type of info. Also I am confused, if you have a poston downpipe with a deltagate, what elbow is leaking?

[justav6]

i dont have a scanmaster yet, but am looking to get one. i have alcohol, but am not currently using it.my air/fuel guage is awful, not accurate. it is the poston downpipe 3" which attaches to the ported out stock exaust elbow. when my car was stolen and turbo removed they took the top of the downpipe, so there is a 2" gap between the elbow and the down pipe.the turbo i have was made to allow an external wastegate to bolt right to the exaust bell ( rare style). i tried to get the piece of downpipe from poston, but it will take them 6 weeks. i really cant afford another $300 downpipe right now either. i was running 17 psi, but at the track i realized some vaccum lines melted so i think i was pushing 12.5 psi with no map sensor. i turned up the boost a ton for my 3rd pass out of frustration, and thought id be making 21 - 22 psi. i looked down at my boost guage and it only read 15 psi. im now replacing all melted lines, but im pretty sure theyl just melt again unless i can seal up that exaust leak. my first run was on premium pump gas 14.0. the next 2 i added some 110 race gas and ran a 14.4 and 14.6. could the engine be choking on its own exaust? right before the track i had to do my dmv emissions inspection so my fuel pressure was way down. after my 1st run i realized that and turned it up. it really didnt seem to like the rich mixture as i stalled after my tire warming burnout, and ran slower times. im just confused at this point, i thought i knew these cars pretty well. are their any gn specialists i can bring it to in nj?

[Hypsi87]

You need to get the downpipe fixed. and if you are running alcohol, you need to get a scanmaster. I almost garuntee that you are running rich as hell. What injectors and chip do you have? Also you need to get a scanmaster if you want to run an external wasegate.

[justav6]

i just ordered the piece for the downpipe, its finally in stock. im not currently using alcohol. the external gate has been working great without the scanmaster, i have a vbc. it is actually much better than the stock style adjustable i used to have. my chip is a custum programed from precision, custumised for all of my upgrades. im using 42.5pph injectors, i belive theyr lucus, if not theyr bosch. im pretty sure i have been running rich, but the first run i couldnt have been, because i came straight from the dmv for an emmissions inspection. nj has the 2nd stricted emissins laws, so i had the fuel pressure as low as it could go with out stumbling. my emmision levels were incredibly low. i forget the numbers, but say the max is 350, i was 18. but my times were a bit better when it was low, i just figured it was because everything was heated up once i turned it up.

[Hypsi87]

you dont need the scanmaster to run your wastegate, you just need it to be able to tell your o2 milivolts and your block learns. Also to gauge your knock sensor. The scanmaster just lets you know what info your sensors are sending your computer. Lets you know what the computer is doing.

[justav6]

yea, everyone i speak with recomends i get one. i have it high on my priority list, but theyr pretty pricy. id like to find someone selling a used one, but thats rare. after all the money i dumped into the car recently to get it back on the road i have to be careful how much i spend and on what.im just a bit upset, because i know it should be a mid 11 second car, and if i cant get it at least to the mid or low 12s by the end of the summer im gonna have to sell it. who needs a 14 second gn?

[Hypsi87]

I have a friend that might have one for sale. I will ask him, I think he wants like 200 bucks for it. it's a 2.1 scanmaster. You have almost the same setup as I do. Accually a tad bit more, your car should be a mid 11's something.

[justav6]

thats what i thought, and what everyone told me, which is why i was disgusted with my 14. do you have any tips i could try in the mean time, until i get a scanmaster? i used alot of the info from the powerpac book, which was helpful. i have everything they mentioned in "getting your tr in the 12s" and "getting your tr in the 11s". plus a good amount more- konis, airbags, bushings in suspension, plus motor trans and bolt ons. all i can think of is just being WAY out of tune. also, since all 3 runs was with no map line, would this theory be correct?> sensor doesnt read the boost through map, so it doesnt increase fuel, which causes detonation, which causes a timing retard, which yields a pathetic et?

[Hypsi87]

All the MAP sensor is for is for the factory boost gauge. It does not tell the computer anything about fuel or air. The MAF is what contorlls that. I will ALMOST garuntee that you are maxing out your MAF. which would not hold you back that much. Once you get it tuned out, you will be good to go.


I have not been able to get ahold of my buddy with the scanmaster yet.
I will let you know when I do.