torqueaddict

I have an 89 L98 TPI (50k mile) - just installed a Scoggin Dickey upgraded Vortec head kit (better springs), with the new base intake, ZZ4 cam, and edelbrock headers.

It's running ok, but it doesn't seem much different than before. Any tuning tips, or what I should expect from this setup? I had read I should expect at least 300 hp from this setup.

Anyway, any suggestions on timing changes, fuel pressure, spark plug gap, etc... over stock settings? I am hoping that after a little tuning it will get much better.

formula_novice

iTrader: (1)

When I upgraded mine (see sig), I noticed a difference in torque right away. Are you running bigger injectors? If you don't have one, I would get an AFPR... that alone helped the throttle response on mine.

That is probably 300FWHP, so alot less is getting to the back tires.

You probably won't notice a big difference until you get the chip tuned.

torqueaddict

I have an AFPR - what kind of pressure do you run? (you measure it at idle, right?)

I don't know much about changing my PROM... I thought that I could use the stock settings for for this setup without issues. Is the memory updatable with software or do I need a new chip. Can I buy one for my setup?

Any more info appreciated!

torqueaddict

As for injectors - I have accel injectors that are the stock 350 size - 22 I think it was...

formula_novice

iTrader: (1)

If I remember correctly, my AFPR is set around 47 PSI (at idle).

In order to configure the PROM for your new mods, you will need a new chip.
You can learn how to burn them yourself (see DIY PROM section) or purchase a custom one from places like TPIS, etc.

Pat Hall

iTrader: (31)

Chip tuning is definitely not a "must do" for the mods you did. Most guys on here recommend it to "optimize" your setup. For one thing, you have a MAF TPI system, and they adapt to minor mods much easier than the 90-92 speed density TPI system. Before investing any substantial amount into chip work, my suggestion would be to try different fuel pressure settings until it feels the best, and also try different settings on the timing. With the better cam and better breathing heads/intake, your motor will probably be happier with more initial advance. Factory setting is 6 degrees before top dead center. Try settings between 8-12 degrees BTDC. If you don't see any major improvement after trying those things, then maybe look into a custom prom. LS racing chips and PCM for Less both have a lot of satisfied people, and their prices are pretty reasonable.

torqueaddict

Thanks - that's what I thought.

Actually over the last few days I've been finding little things that are making the car run much better. (vacuum leaks, and I mixed up the pcv valve with the air tube)

Also, I think I was expecting a more dramatic increase in power but it's more subtle than that. It definitely pulls harder through the midrange and I get a more consistent chirp on the 1-2 shift but like I said - not dramatic.

I plan to take the car to the dyno soon and do a little tuning there.

APACHE JOHN

Chirp on 1-2 shift? My stock 91 Z28 would burn the tires going into second something ain't right.

torqueaddict

How good were your tires? I have BFG g-Force sports and they do seem pretty sticky.

I was also wondering what people are running on their SD vortec as far as plenum/runners. I wanted to get a super ram but it's looking like they are discontinued... so now I am looking into which runners are best.

86LG4Bird

iTrader: (1)

This thread just caught my eye, since I'm currently in the process of installing a new GM L31 Longblock (w/Vortec heads) with a ZZ4 cam in my '98 pickup. The original Vortec engine in it was very strong even with the baby stock cam, so I'm expecting it to really come alive with the ZZ4 cam.

torqueaddict, A few questions for you:
Do you know what compression ratio you ended up with? What head gasket thickness? I assume your motor has flattops with the 4 valve reliefs and the typical deck clearance of about .025 in the hole..?? With the Vortec head 64 cc chamber, I'm guessing you could be anywhere from low 9's to low 10's CR, depending on gasket thickness and actual deck clearance.
On my truck, I lelected to leave whatever gasket GM put in the longblock to keep it down at 9.4 CR since I tow a lot and will continue to run 87 fuel. If running better fuel, I would have definitely popped the heads off and replaced the gasket with a thinner one.
After I get it running, I'll check back in here and let you know my impressions on the present tune.
Going from your L98 heads and stock cam to the Vortec heads and ZZ4 cam, I would think you'd notice a BIG difference.