andy-gts

I was wondering what you guys thought about a planned project. I want to port and polish the heads and put some hotter cams in the 93 gts. two questions
1) I have the motivation and wsm but never tackled cam and heads before..should I do it myself or just go to my favorite mechanic.
2) any body have any experience with 928 developments and their products.
thank you for any comments.
Andy

Chris

Go buy some GT cams and put them in your GTS, can do this without removing the heads and a nice bolt on improvement especially if you have a 5 speed. Hotter cams in an auto may lead to some idle issues.

Chris

Rick Carter

I ported and polished, a small part of how I got to NA 291 rwhp in my 85 32v. Bang for the buck install a SC, your current cams especially intake are very boost friendly, do a search on dynanmic compression.

6.0-928S

Andy,
I ported my own heads but I've been doing my own heads for 35 years. I don't think it's a good idea to start your porting career on 928 heads. They are the key to making HP on this motor though. Funny this comes up today. I just finished mine & I happen to be assembling them. Yes I'm doing it on my coffee table, - so I can watch the football game! Here's some pics-
By the way, I have dealt with 928 Developments, pm me.
Hammer

RyanPerrella

NICE

I love that your doing that on your coffee table, and why, cause Football's on! I am about to get some of that bilders blue and lap my valves in on my heads in a day or two. Any suggestions, i know its pretty straight forward but would love any helpful tidbits you could share.

As for porting, i dont think you will get much out of it honestly. Also have heard that GT cams in an auto will give you problems as it produces differing vacumn levels. I dont know how all that works but apparently it isnt good, so i second the previous post about idle issues.

I also have to agree that even with GT cams and porting work you may only gain 10 maybe 20 HP. You need to do other things to take advantage of that. I have to say that the castings are pretty good on my GT heads. Its been said they were given more attention at the factory then the other heads but they look pretty clean, no obvious airflow issues. Obviously if you enlarge the ports you can increase airflow but possibly at the expense of soemthing else. If you want more power then go with one of the few superchargers available. I dont think you would be happy with the cost per HP figure of porting an otherwise stock engine.

ZEUS+

All of the above is wise advice. If not done properly porting can lead to uneven flow characteristics.

6.0-928S

That's true.."If not done properly"

This is the first 928 engine I have built. It is not, by far, the first performance engine I have built. I'm aware of the changes I'm making.
My cams are custom grinds bigger than GT cams. Porting, larger valves, cams & headers will wake this engine up. A hell of a lot more than 10-20 HP. I don't go by what I HEAR, I go by what I've learned from previous racing engines I've built. Although they weren't 928 engines the fundamentals of V8 racing engines don't change. Within the constraints of timing & reliability one thing doesn't change from engine to engine.....
More air & fuel in, more air & exhaust gases out = more power.
I know what rpm I expect this engine to idle at & it won't cause a problem with an automatic transmission. Besides, even if I went wilder it's nothing a higher stall converter wouldn't handle.
As for cost, I ported the heads & I didn't send myself a bill. I designed this engine as a PACKAGE. Porting, valves, headers, cams, compression, & I'm still under the price of a blower.
The fun of American hot rodding is in building it yourself in my opinion, not just buying a blower kit & bolting it on. Some people do it that way & I can respect that. But to me, the fun is in the accomplishment of doing it yourself & it has always rewarded me.
Regards, Hammer

Louie928

I doubt if porting will do much for you. A little clean up of casting roughness might help some, but don't get it too smooth, or change the shape. Some surface roughness will help fuel that's on the port wall get back into the air stream. The one thing that will help is to get rid of the GTS cams. The GTS intake cam isn't too bad, but the exhaust cam is what costs the GTS performance. Cheapest way is to keep your GTS intake cams and use S4 exhaust cams. The next step better is to do as Chris Ford suggested and go with GT cams.

RyanPerrella

Hammer 6.0L

When i said 10-20hp i was refering to the posters original question on an otherwise stock engine.

RyanPerrella

also as to the original question of doing it yourself. Cam changes can be done by yourself. When you remove the heads thats when you are doing partial engine teardown.

I would trust louie's advice for the cam selection. I didnt know GTS cams were that different from S4 cams, but i am sure you could find a pair of S4 exhaust cams fairly reasonably. That maybe a worthwile upgrade.

Stan.Shaw@Excell.Net

I have a set of S4 cams that are for sale.

mark kibort

if you want to go cheap, but effective, do the 85 cams and have the driver exhaust cam modified to fit the S4/GT/GTS heads. (the rest are pretty much a bolt on ) Lift is highest on the 85cams and the GTcams. GTS are in between the GT and S4.

I think what you really should do is the 928 developments intake!

MK

andy-gts

wow , thanks for the advice guys.i have read rennlist alot the last 3 years and now feel ready to take the gts to the next level. I want to flow about 850 cfm through the intake and I seem to have a hard time connecting with devek. 928 developments seems to be able to supply parts .
I was thinking of a hotter cam profile than GT though. my goal is 460 to 480 hp and I am just starting down the road.
Thank Again for all your help
Andy

RyanPerrella

not sure if your going to get anywhere near 460 let alone 480 hp on just cams and a stock 5.4L bottom end.

And for whatever reason, GTS's seem to make less HP then the 5.0L GT engines.

If you want 480 i think your best bet is a supercharger for 7K or whatever they cost. To get 480 out of a NA car your going to spend double if not more.

Louie928

If your goal is that much (rwhp?), you'll need larger valves as well as more cam than a GT and probably a different intake system. You'll need to turn it higher RPM too so plan on crank & oil control work. If you have an auto trans, maybe a higher stall speed tq converter.