Iwanna928

Well I finally put out all of the fires and got the car dyno tuned! The car ended up needing 6 degree advance in timing from where it was. The tuner did a great job. He was familiar with 928's and is currently looking at a GTS down in Ft Meyer's.

Original dyno, 4.5L w/ headers and duel exhaust was 203rwhp

With euro cam's added it went to 238rwhp and 245rwtq. This was on a Dyno Jet.

After dialing her in he suggested that I go with a safe tune for the street and the Fl sun and the fact that the car will be taking a 1300 mile trip tomorrow. He backed the timing down and we stayed at 225rwhp and 245rwtq. Air/fuel ratio was a solid line of 13.88 and 13.99.

He was very impressed with how strong the motor ran. He had owned a 78 928 in the past and a 928S. After we were done he asked if he could take her for a drive and he loved her!

I felt very comfortable with the results, and was very happy! He stated that Jose did a awesome job and couldn't believe how cheap it was. Timing belt, euro cams installed 300 bucks! Jose ROCKS!

More to be revealed!

Stephen

terry gt

Very nice , you will have to try the 1/4 mile again !

Iwanna928

Coming up Terry! That will really tell what the cam's do for the performance. I do not put much weight on a dyno but it helps. The track will tell me where I really stand! Need to see what she will do w/ your top end and a 5.0L

Speak to you soon!

Stephen

IcemanG17

I would be a bit concerned at AFR of 13.8-9 at high RPM....that is a touch lean for comfort....you should gain a couple HP by getting it down to say 13.0 at 6000rpm...... Which is NOT easy given the CIS system...

danglerb

How was the a/f measured? I was expecting a lot more variation.

LT Texan

35 horses with just the cam change? Nice! I was worried about that cam and the 8.5:1 compression ratio, but looks like a good result.

You've installed the Euro S cam right?

I've really got to get mine to a dyno to see what I've got with Euro S cams and heads on my otherwise stock 4.5l with Borla cat-back.. Would be nice to compare. And would be nice to check/adjust my a/f ratio. (Tailpipe looks slighly rich.)

Fabio421

It was a 22HP gain. The 35 HP gain was with the 6 degree timing advance. Thats not a true #.

Stephen, what was the total advance before you tweaked it and what was it when you left it alone?

BTW, $300 for labor to do a TB and a cam change is sweat shop wages. That was a great deal. So how does the car feel now compared to before? Can you post the dyno sheets?

Iwanna928

I would post the dyno result but I don't have a scanner.

If someone had a scanner I could fax them the dyno sheet.

The air/fuel line always looked very linear throughout all of the pulls. I don't know if that's bad but it stayed very consistent. I also don't know where the timing ended up.

I need to find my first dyno and see the results to cpmpare them. The car seems to pull real nice and strong. Nothing mind blowing but a nice improvement for sure. With some nice heads it would be a sweet combo on the 4.5L. It sound very nice! The exhaust I have seemed to raise the powerband before so I didn't really notice a big shift. With my exhaust it seemed to come alive arourd 3800rpm and pull hard to 6k.

I will probably bring it back to my regular guy that did the first dyno. He was busy yesterday and I wanted it to get done.

Stephen

Stephen

LT Texan

that's odd. I understand the CIS is engineered to richen as rpm's increase under load.

hacker-pschorr

See if the dyno owner / operator will e-mail you the dyno files. You can then download the Dynojet software free from their website. There are plenty of us familiure with the software if you have issues putting the chart together.

Did you do any timing adjustments with the stock cams after the headers were installed?

What spark plugs are you using?

What kind of advance are the cams set to? Any idea how the stock units were setup?

Iwanna928

Hacker No timing adjustments were made to the original setup. The car came with headers. The plugs are the ones that came with the car so I again have no clue. I also don't know about the cams but jose used the same marks that were on the car before.

I will call the shop about the file.

Sorry not much help. I think there could be more dialing but I think it is safe to say the cam's are worth at least 20rwhp. Heads maybe another 20? Which if thats the case will bring a 4.5 with header and this combo to 240rwhp maybe a little more.

Thats a healthy and fun OB to drive and a lot of people might be happy with that and call it a day.

Stephen

hacker-pschorr

I ask about spark plugs since IMO the stock 78-82 spec plugs are too hot, especually for a modified car running more timing.

I would also make sure you are using copper plugs gapped to spec. If it were my car, at least 1-2 ranges colder than stock. One range colder will be the same spec for the "S" cars, 83-84.
Copper plugs are cheap. I'm using two ranges colder than stock with a non-projected tip. I have yet to experience any fouling or running isuses during aroud town, daily driving. Granted I never drive my 928's in temps much below 50 degrees.

How is the oil breether system? If that is still stock, there are some room for improvement. Either something like DR's SharkVent or some other way to further seperate the oil from the air before going back into the engine. There are a lot of threads on this.

mark kibort

impressive numbers. you had a great base to start with, getting 200rwhp stock, or was that with headers? I think it was. I got the same number with my 84 4.7, 200rwhp with only headers and exhaust. cams and INTAKE took me to 243wrhp. who knows what the effects were with the heads later when added to the 5 liter bottom end. one thing I did note, is that timing was set at the stock 20 btdc with vacuum removed, but at high rpm normal, it was near 37 degrees I advanced it to 42 degrees and didnt see any more hp , only gains in peak torque. going to 45 degrees it lost HP. anyway, it would be interesting to see how the timing changes effected your runs during your tune session.

what kind of dyno?

send me your dyno runs and Ill post them. pm sent

Mark

Iwanna928

Hacker I will change the plugs per your recommendation when I get back from Atlanta. Any plug recommendation?I have seen the shark vent system and it looks sweet. Wanted to see it there was another way to do this w/out spending to much cash. I will have to do some more reading! That sould probably be the next issue tackled.

Stephen

hacker-pschorr

Stock is WR8DC
8 = Heat Range (Bosch number goes lower as the heat range drops)
C = Copper

WR7DC = One range cooler for 78-82 (stock for 84-95)
WR6DC = Two ranges cooler for 78-82 (personally what I would be using in your car)
WR5DC = Three ranges cooler for 78-79.....

I'm using NGK plugs, they do not directly cross over, this is a rough comparison
WR8DC = BPR5ES
WR7DC = BPR6ES
WR6DC = BPR6ES / BPR7ES
WR5DC = BPR7ES / BPR8ES

The "P" in the NGK plug stands for "Projected". I'm using the "Non-Projected" plugs.
Same part number, just drop the "P" from the part number.

Worst case scenario is fouling on cool days, stop and go driving etc…. with too cold of a spark plug. Down in your climate this makes things much easier.
Like I said before, I'm using BR7ES in my 81 and haven’t experienced a fouled plug yet. I've purposely lugged my car around when cold to test the plugs. I have the same ignition system as yours.
These plugs are cheap and easy to change. I pay less than $1.75 for the NGK plugs at a local “Farm and Fleet” store (they are used in snowmobiles).

Bare minimum I would be using the 84+ Bosch Copper in your car.

Discussion on this topic are more religion like what oil to use.

Mike Schmidt’s paper posted on Louie Ott’s site is a good place to start (can anyone help with a link????)