Dyno results. Greg Good heads, Gen I.

[Alley]

Car also has Belenger headers, roe racing mufflers, cat delete, 3.73s. Heads were ported, polished, and milled. Peak #s were 390rwhp, 432rwtq. This is on a Mustang dyno. This one is typically 10-15% lower then a dynojet. Previous #s were 360/427. So a pickup of about 30rwhp, and 5rwtq. But as you can see by the graph the peak #s don't mean anything. My torque stays high now though the entire RPM band and doesn't drop off like before. Its about a 20rwtq gain through the entire band. And we peaked at about a 40rwhp increase from 5-6krpm. These numbers are pretty much what I expected from talking to other Viper owners. We got the AFRs where they need to be and added a couple degrees of timing.

I wanted to do rockers at the same time, so I got some Gen III ones cheap thinking they would fit but it was a no go. So I had to put the stock ones back on untill I can find some used T&Ds for cheap.

The butt dyno confirms the gains. Car feels STRONG.

Graph is before and after head work.

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[plumcrazy]

What are you tuning with ?

Power under the curve! Nice.

 

[Alley]

VEC 2...............

 

[SquadX]

id sell the Vec and go SCT, if money permits and i am sure when you get RR that you'll see an even nicer gain.

 

[eucharistos]

nice re-curve

 

[KenH]

Looks like some nice gains, but your dyno shop should increase the filter value. Using a filter value of 1 leaves a lot of noise in the graph and that can give erroneous readings.

 

[Twister]

Car also has Belenger headers, roe racing mufflers, cat delete, 3.73s. Heads were ported, polished, and milled. Peak #s were 390rwhp, 432rwtq. This is on a Mustang dyno. This one is typically 10-15% lower then a dynojet. Previous #s were 360/427. So a pickup of about 30rwhp, and 5rwtq. But as you can see by the graph the peak #s don't mean anything. My torque stays high now though the entire RPM band and doesn't drop off like before. Its about a 20rwtq gain through the entire band. And we peaked at about a 40rwhp increase from 5-6krpm. These numbers are pretty much what I expected from talking to other Viper owners. We got the AFRs where they need to be and added a couple degrees of timing.

I wanted to do rockers at the same time, so I got some Gen III ones cheap thinking they would fit but it was a no go. So I had to put the stock ones back on untill I can find some used T&Ds for cheap.

The butt dyno confirms the gains. Car feels STRONG.

Graph is before and after head work.

You must be registered for see images

Give this to me so I understand.

With the other supporting mods on the mustang dyno you hit 360 rwhp???

Then after the adittion of the GG heads you hits 390 rwhp on the same dyno..

What year is your car?

if it's a gen2 Viper you should be at 390-410 rwhp on a dyno jet..

then with the mods you have listed headers/exhaust no cats you should be at 425-445 rwhp on a dyno jet.. ( but you got 360 on the mustang dyno with this set up correct?)

Then with the GG heads (lightly touched correct?) I would assume a 35 PLUS rwhp increase to 460-480 rwhp..(but you hit 390 rwhp on the mustang dyno correct?)

Im just kinda haveing a hard time getting this figured out..

390 rwhp on a mustang dyno that reads 15% under a standard dyno jet would only equate to aprox. 455 rwhp SAE on a dyno jet.

THIS NUMBER SEEMS LOW TO ME FOR HEADERS/EXHAUST/NO CATS/AND THE MAGIC OF GG

or am I mis reading somthing..

THANKS

 

[Twister]

OK Im gonna try the math differantly...

If on a dyno jet you would be at 460-480 rwhp with your set up based on my average circumstances numbers..

Well just say you would dyno 470 rwhp tomorrow on a dyno jet with your current set up..

470 rwhp minus 15% equals......

400 rwhp on a dyno jet


WHEWWWWWW!!!!!

Took me a lil while to figure this mystery out...

So if it truly is a 15% dive train loss then you will dyno aprox 465 rwhp on a dyno jet...

Wich with your mods is about right...

Sorry man and I know Im long winded but that 390 rwhp number just really threw me for a loop for a second..

congratulations on the strong running gen2....that power under the curve must be a real kick in the teeth!!!!!!!!!

 

[Twister]

ha ha ha.....Im feeling really stupid now...I was really wondering why you ionly picked up 35-40 rwhp ect...


you have a gen1.....I thought you had a gen2....SORRY..

Now Im really impressed..A 465/505 rwhp SAE gen1 on a dyno jet with such mild mods is AWESOME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1

 

[Alley]

Glad you figured it out Twister. lol I actually do think my numbers might still be a bit low even for a Gen I for my mods. I've seen guys post up with higher numbers. Before the heads and tune I put down 400/468 on a dynojet.
I'm no expert on dyno graphs. So what do you guys mean by re-curve and power under the curve?

 

[SquadX]

i thought your numbers were a bit low too myself but nice gains in the mid ranger were it counts. I'd look into a retune. How extensive of headwork did you have Greg perform? Gregs one of the best, if not the best at porting heads and I sure he did a great job on your heads, as you can see from your midrange gains but its all in how extensive the heads were done. maybe you need a different cam to see higher gains. Head work alone will only give you so much. Rockers and cam, in my view, are must haves with ported heads. if you can swing it, get one of Gregs cams. Besides the sound, its a nasty cam, in a good way. My car run like a champe with Gregs cam.

 

[Alley]

He got the heads flowing at 277cfm which he felt would give me the best gains for keeping the stock cam. I couldn't afford new T&Ds at the time, but as soon as I can pick up a used set I'm going to throw them on.

I don't know if the gears take away any HP or not. I've seen a million threads on that topic lol.

 

[Russ M]

Who did the tune?

That looks like a lot of detonation, which would explain your heat issues.

Whats the air/fuel? How many degrees of advance at the various rpms?

I would NOT be driving that car right now.

 

[Alley]

Where are you seeing the detonation? If your talking about the jagged curves, thats the way all his graphs look. Might be that filter setting. My previous graph before heads was the same way. I could go get a dynojet graph from the other shop and it would be smooth.

My AFRs are in the high 12s. We did 2 degrees of advance in the entire RPM band, and 1 extra degree from 5k rpm on.

 

[Russ M]

No reason to have your car be anywhere near high 12's for a/f, when my car was NA there was no power gained being leaner than 12:1 and at high rpm 11.9:1.

You cant just add 2 degrees across the entire rpm band viper motors have detonation problems at peak torque.

What are you using for air/fuel readings? If you say tail pipe sniffer, then that would be even a bigger problem. Those typicaly read lean, so coupled with your hi 12's a/f your car is probably in the mid to hi 13's, which will without a doubt make it run hot.

 

[plumcrazy]

im assuming woodhouse tuned it ?

 

[Alley]

No, the tuner is on the dyno sheet. I'll bring these things to his attention and see what he thinks.

 

[Alley]

Talked to the tuner. Here's the basics of what he said.

I filtered it at 1 because when I print if off it shows the actual power/tq figures. If I change the smoothing it averages the highs/lows and drops the hp/tq numbers by a little. I only added timing at WOT so the running hot is another issue. I would say to get a switch on the fans to start with. As far as detonation goes There was 1 time when I added 4 degrees it detonated just a little. It never detonated at the 2 that is in it now.

 

[AndyMac]

id sell the Vec and go SCT, if money permits and i am sure when you get RR that you'll see an even nicer gain.

Correct me if I am wrong, but the SCT is only good for the gen II and up. (OBDII vehicles)

Later,