Ported milled heads on bolt on car

[T/A KID]

Hello, what is current opinion on ported G5 heads on a bolt on car?? I’ve seen a couple of examples over the years from Greg good and others and seems like a nice upgrade even with the stock camshaft.. was curious if there were any more examples??

I’ve collected quite a bit of info on this board and others and it appears factory CR is 10.19 for our stock G5 engines, not sure on flow numbers but I’m guessing roughly 330 at .600 lift stock.

Currently I have AR headers no cats (factory mufflers), Ipsco underdrive pulley, hp tuners tuned by myself. I was doing a 4l80e swap, but didn’t want to cut the tunnel so now have a 6l90e going in. Plan to write a second tune for e85 using a set of demon injectors which are 65lb hr.

So this is my plan, utilize stock cam (I believe it’s 23x 22x stock but valve lift is under .500) But if I can gain some flow and bump compression from 10.1x to roughly 11.3 that’s should be worth 3-4% more power (20 hp roughly on a 700hp car, just from compression) still be fine on 93 pump and e85 would love it.

It’s my understanding factory fuel pump is rather good on the G5 platform so simple injector upgrade and stoich change is all that would be really needed to swap in the calibration my 93 to e85.

Todd at Ac performance listed stock G5 head at 71-72 CC and factory gasket thickness at .048.

CC on milled heads could drop to 65 and cometic could do some gaskets around .027-.030 which would technically put compression roughly 11.5.

What’s everyone’s thoughts?

[Lawineer]

If you’re going to to go that far, why wouldn’t you swap the cam?

If you’re running e85 that’s one thing, but I’d venture to guess you’ll have to pull some timing on pump if you increase compression by about 10-15%. Wouldn’t surprise me if you netted nothing at all (or worse) on the compression increase on pump gas. But thats a wild guess.

[T/A KID]

Very good point.. I thought about a camshaft, Compcams is local to me and know several people
There that would set me up with a mild cam. But I don’t really want to go down that rabbit hole, lifters, custom springs for over .600 lift, VVT delete, etc. adds up.

I run 30 degrees at WOT now and .85 lambda at 10.1, that timing probably would need to drop to around 27 with the compression jump but still be more efficient with less timing and more compression in my opinion.

[Lawineer]

Generally, correct timing is more important than getting a little more compression. If you start ignition while it's on the upstroke, that's bad

Anyway, I'd imagine you can upgrade without getting an insane cam that requires new lifters and springs and etc. But you're already swapping heads which presumably means springs too.

[V10LEE]

On my Get 2 1997 GTS I had Jeff Morey stage 3 ported heads that were milled bumping up the compression a point.Along with American racing stepped 5 in to 1 headers plus cam. Power was amazing bumping up the compression. One thing which was crazy was I had Belanger headers and when we swapped out to the ARC headers made like over 20 rwhp more! I was blown away Dan Cragin did all the work at DC Performance. JM heads the best too! In total car put down 600rwhp on 91 pump gas..

[Aevus]

Hello, what is current opinion on ported G5 heads on a bolt on car?? I’ve seen a couple of examples over the years from Greg good and others and seems like a nice upgrade even with the stock camshaft.. was curious if there were any more examples??

I’ve collected quite a bit of info on this board and others and it appears factory CR is 10.19 for our stock G5 engines, not sure on flow numbers but I’m guessing roughly 330 at .600 lift stock.

Currently I have AR headers no cats (factory mufflers), Ipsco underdrive pulley, hp tuners tuned by myself. I was doing a 4l80e swap, but didn’t want to cut the tunnel so now have a 6l90e going in. Plan to write a second tune for e85 using a set of demon injectors which are 65lb hr.

So this is my plan, utilize stock cam (I believe it’s 23x 22x stock but valve lift is under .500) But if I can gain some flow and bump compression from 10.1x to roughly 11.3 that’s should be worth 3-4% more power (20 hp roughly on a 700hp car, just from compression) still be fine on 93 pump and e85 would love it.

It’s my understanding factory fuel pump is rather good on the G5 platform so simple injector upgrade and stoich change is all that would be really needed to swap in the calibration my 93 to e85.

Todd at Ac performance listed stock G5 head at 71-72 CC and factory gasket thickness at .048.

CC on milled heads could drop to 65 and cometic could do some gaskets around .027-.030 which would technically put compression roughly 11.5.

What’s everyone’s thoughts?

Sure you will benefit from ported Gen 5 heads without having a bigger cam?

don't know the numbers on the Gen 5, but stock Gen 4's are flowing pretty good already:

http://speedstore.ca/VP4_flow_sheet.html

327 CFM @ 0.600 lift

Gen 4/5 bottleneck doesnt seem to be the heads flow...

[Aevus]

as far as Gen 5 (serious) HP gain goes:

A) Stroker 9.0L

B) Turbos

[T/A KID]

Talked to PAC springs today, they have a nice beehive spring for the gen4/5 viper heads.. talked to them about TI retainers for little less Valvetrain weight, but since keeping RPMs at 6400 (200 more then stock) they didn’t see much gain over steel retainer in their opinion.

[T/A KID]

Sure you will benefit from ported Gen 5 heads without having a bigger cam?

don't know the numbers on the Gen 5, but stock Gen 4's are flowing pretty good already:

http://speedstore.ca/VP4_flow_sheet.html

327 CFM @ 0.600 lift

Gen 4/5 bottleneck doesnt seem to be the heads flow...

That’s about what I guessed they flow… compression gain in my opinion is where the main gain is with what I’m wanting to do. Naturally if I had a .650 lift cam with 24x25x duration and tighter LSA then head flow would make a bigger difference. In fact porting the heads on an app like that would be different then say one with a stock cam..

I’ve seen 650rwhp with headers, ported heads/compression jump, tune with 91 octane so I know the power can be made..
I calibrate cars for a living and believe we can do better then this even.. I started another thread, but was looking last night and I think I can fit some GM ls7 or Ltx 1.8 rockers on the viper little valve lift and some e85 would jump power quite a bit

[Lawineer]

That’s about what I guessed they flow… compression gain in my opinion is where the main gain is with what I’m wanting to do. Naturally if I had a .650 lift cam with 24x25x duration and tighter LSA then head flow would make a bigger difference. In fact porting the heads on an app like that would be different then say one with a stock cam..

I’ve seen 650rwhp with headers, ported heads/compression jump, tune with 91 octane so I know the power can be made..
I calibrate cars for a living and believe we can do better then this even.. I started another thread, but was looking last night and I think I can fit some GM ls7 or Ltx 1.8 rockers on the viper little valve lift and some e85 would jump power quite a bit

That's about 100hp gain, give or take. What will a typical G5 with headers, exhaust and a tune make about 80 more hp (call it 60 for exhaust and 20 for tune)?

Using the old rule of thumb that 1pt is 3-4% power on compression (20hp), it seems like porting the heads isn't doing much of anything. Which kinda makes sense from everything I've heard about them.

[txA&M08]

That's about 100hp gain, give or take. What will a typical G5 with headers, exhaust and a tune make about 80 more hp (call it 60 for exhaust and 20 for tune)?

Using the old rule of thumb that 1pt is 3-4% power on compression (20hp), it seems like porting the heads isn't doing much of anything. Which kinda makes sense from everything I've heard about them.

I was always under the impression headers and Arrow PCM make around 40-50rwhp. Stock 530 to Arrow/exhaust 580ish seems typical. Just anecdotal from what I've observed over the years.

[T/A KID]

That's about 100hp gain, give or take. What will a typical G5 with headers, exhaust and a tune make about 80 more hp (call it 60 for exhaust and 20 for tune)?

Using the old rule of thumb that 1pt is 3-4% power on compression (20hp), it seems like porting the heads isn't doing much of anything. Which kinda makes sense from everything I've heard about them.

Honestly I think it’s the compression jump more than anything too. I think increasing runner volume on a bolt on app could be counterproductive but someone like Greg good would know.

[Lawineer]

I was always under the impression headers and Arrow PCM make around 40-50rwhp. Stock 530 to Arrow/exhaust 580ish seems typical. Just anecdotal from what I've observed over the years.

I thought it was closer to 60/65whp, but even 50whp, that's 40rwhp for compression and porting. Attributing about 20whp of it being compression, is it really worth porting heads for 20rwhp?

[txA&M08]

is it really worth porting heads for 20rwhp?

If I was bored, childless and rich it sure would be

[Steve M]

It’s my understanding factory fuel pump is rather good on the G5 platform so simple injector upgrade and stoich change is all that would be really needed to swap in the calibration my 93 to e85.

I'd do some homework to see if your fuel pump is up to the task. My understanding is that it can support ~700 crank HP, but beyond that it can't keep up with the demand. I have a feeling E85 might be a bridge too far without an upgrade.

Prefix would know for sure.

[T/A KID]

I'd do some homework to see if your fuel pump is up to the task. My understanding is that it can support ~700 crank HP, but beyond that it can't keep up with the demand. I have a feeling E85 might be a bridge too far without an upgrade.

Prefix would know for sure.

Thanks Steve, I’ve talked to Scott over there before, I may pick his brain.. worst case I’ll try it and data log with my WB and find out ha

[T/A KID]

Steve by the way is this you??
MeentSS02??
https://forum.hptuners.com/showthrea...n-5-Viper-read

I’m Ben Charles from Hp tuners

[T/A KID]

Looks like prefix sells a nice pump upgrade for gen 4/5s
I bet it’s a 450lph pump
https://store.prefix.com/products/hi...it-g4-g5-viper

[Steve M]

Steve by the way is this you??
MeentSS02??
https://forum.hptuners.com/showthrea...n-5-Viper-read

I’m Ben Charles from Hp tuners

One and the same.