basic mods done. What to expect? any advice welcome.

H

HouTX87

Active Member
Joined
Nov 21, 2011
Hey guys, '87 GN owner for about 3 months now. I've done alot of reading on the site mostly so far. Great info here. Anyway the car was mostly stock 45k miles with underdrive pullies, upgraded plug wires, hypertech chip, and flowmaster catback.

So far I've installed:
scanmaster
boost gauge
replaced motor mounts and trans mount
walbro 340 fuel pump
racetronix fuel pump hotwire
accufab adjustable fuel pressure regulator at 43 psi
turbo tweak 93 octane street chip
matching 42lb injectors
R43TS spark plugs gapped to .035
2 1/2 test pipe to fit stock down pipe.
(other minor repairs)

Next on the list:
Cold air intake with stock MAF sensor (any recommendations?) Been thinking Fullthrottlespeed kit
Pypes catback
adjustable wastegate
rjc powerplate
ALKY injection

With the stock wastegate actuator still installed I'm only seeing around 14 psi max boost since I put in the turbotweak chip and injectors. The hypertech chip was overboosting at 17psi.
Will installing intake and catback effectively increase the boost or should I install the adjustable wastegate first and then work backwards?
 
Sooner or later you will need an adjustable wastegate actuater. Might as well get one. In my case the OEM actuater was over-boosting to 20+#'s.

Some cars run at 17#'s on pump gas just fine.

~JM~
 
shortening the rod raises boost,lengthening it drops boost.dont get boost crazy till you get alky or add race gas.boost is power but you need the octane.if the exhaust is good leave it alone,along with the intake,just put a kn filter in the stock assembly.
 
I'm wanting to try to get near 16 - 17 psi boost on pump gas if I can tune for zero knock. 14psi seems very conservative but definitely safe.

So an aftermarket cold air kit and up pipe would not be worth the money? Anyone know a part number for a stock K&N replacement filter? When I checked on a stock paper air filter at autozone they didn't have one.

I read an article in gmhightechperformance where installing a pypes catback on a nearly stock engine made an additional 40 rwtq. I've read nothing but bad things about the flowmaster suitcase setup and how it isn't any better than stock.
 
HouTX87 said:
....So an aftermarket cold air kit and up pipe would not be worth the money? Anyone know a part number for a stock K&N replacement filter? When I checked on a stock paper air filter at autozone they didn't have one.

I read an article in gmhightechperformance where installing a pypes catback on a nearly stock engine made an additional 40 rwtq. I've read nothing but bad things about the flowmaster suitcase setup and how it isn't any better than stock.
Click to expand...

Fresh air intake & exhaust mods are definately worth extra power. I have a K&N type of filter (I prefer AFE to K&N http://afepower.com/ ) attached to my MAF & removed the original filter canister. That change alone started breaking the rear tires loose with moderate acceleration.

The Pypes exhaust is a nice system that offers documented gains.

~JM~
 
NAPA has replacement paper filters that fit the OEM filter canister.

~JM~
 
Leave the intake alone for the level your at and just get an adjustable wastegate cause with the alky you'll be able to run much more than 17 lbs. Another good option will be a downpipe.
 
x2 on the downpipe. i saw the most gain from a down pipe when i was mostly stock
 
Really? A downpipe before going to a high flow catback? I eventually want to install complete exhaust starting with a 3" downpipe and pypes catback. But if I can't afford to do it all at once which would be more benefecial? Downpipe or catback? If I could run an open cutout on the street all the time then I'd say screw the catback but it is primarily a street car.

My plan is to maximize my combo on stock motor, turbo, and intercooler before adding alky and cranking up the boost. I'd like to see numbers in the mid 12 second range on pump gas alone. Is this just wishful thinking?

I have test pipe on now to replace the cat (brian at gbodyparts.com had it made for me. I've had really good experience with these guys.) The test pipe made a really noticeable improvement so it seems obvious how restrictive the factory exhaust system is.

I've also bought a set of comp 980 valve springs but haven't yet had a chance for that project yet.
 
Have you ever looked at the elbow on the discharge side of the turbo? I can just picture the hot gasses leaving the turbine & slamming into that damn near 90 degree wall. I think there would be a lot of turbulence there. You already have a cat-back system even though you may not be pleased with it. I would look at the down-pipe by TA Performance or RJC. Then do the rest of the exhaust when you are able.

~JM~
 
Great advice. Thanks. Any opinions about the gbodyparts 3" downpipe?

Are you guys able to get away with driving around with an open cutout on the street or is it too loud for cruising/cops?
 
You definitely want at least a K&N 9" open air filter, the stock air box is very restrictive, saying otherwise is nonsense. Go to any TR show and check the air filter assemblies, I've been going since '93.

http://fullthrottlespeed.com/itemdesc.asp ic 404RE-0810 eq Tp

Get an RJC boost controller and you won't have to mess with the wastegate rod for the levels your looking for.

http://rjcracing.com/product/boost-controller/

Go with a taller oil filter such as napa 1036 and run ZDDP unless you have a roller cam.
 
I was wondering if the rjc boost controller would be effective on my application but I don't see why not. You guys have got me sold on the down pipe now.

I'm using a acdelco PF52 oil filter and valvoline VR1 20w50 non synthetic. I still added a bottle of zddp from kirbans just to be safe.

I just ordered the valve spring removal tool from cottons today. http://www.cottonsperformance.com/proddetail.asp?prod=VST&cat=81
 
If you're using VR1, you can get away with 1/2 bottle due to the high zinc level in it already. That is from Richard Clark who 'created' the stuff, so I hear.

If you get the 52s with the metal cage inside, which I doubt anymore, go for it. Otherwise if they are plastic, head over to Napa.

You could of borrowed a valve spring tool from Autozone, but whatever. Remember, you have to use a length of rope, or compressed air when you remove the spring with the heads on the car - but you already knew that :D Replace the intake valve seals with Viton (blue) seals while your at it.
 
Yeah I've got the adapter from my compression tester. I didn't mind buying the tool. I'm sure I'll use it again some day. I have a different style spring compressor but I don't want to be fighting #6 once I get in there.

The gbodyparts dp looks similar to the taperformance dp. There is a long write up on their website. Price is similar.

http://www.gbodyparts.com/product_info.php?products_id=402
 
I like that concept but the external wastegate looks a little too far from stock than I'm ready to go at this point. But my attitude could change lol.

The turbonetics boost controller couldn't be used with an internal wastegate?

If I install an RJC boost controller will I still need an adjustable wastegate actuator or can I get by with the original?
 
tnetics boost control works on an internal gate.you dont need all those parts to run 12's.a friends stock gn with a chip drag radials,fuel pump,scanmaster went 12's.guys are going 11.0's on the stock intake system in tsa.want to go faster the car needs boost and a good hook.then you will need a trans upgrade.
 
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