Dynosheet, need opinions!

[AbdullaGT500]

Just got the car dynotuned for the hp performance turbo kit, and just wondering if this looks normal? I'm thinking the clutch began to slip past 4500

 

[JeremyH]

Usually slipping is more spikey. Do you have the boost curve?

 

[AbdullaGT500]

What do you mean the boost curve?

 

[JeremyH]

The tuner should have a sensor he puts int he vac tubing to measure boost throughout the run( records boost throughout the pull just like the hp/tq) it shows you where full spool is and if your experience wg spiking or boost drop off up top from back pressure on the wg.

It can be displayed down at the bottom like a/f.

 

[JeremyH]

With out that boost data just lookig at your graph looks like its building boost around 32-3500 and doesnt full spool till around 4300rpms, just a guesstimate based on how your power comes in.

 

[AbdullaGT500]

Hmm, well I guess I'll have to call him tomorrow and see. So it should have continued to make more power past 4500?

 

[JeremyH]

Hmm, well I guess I'll have to call him tomorrow and see. So it should have continued to make more power past 4500?

It does fine up there, its still gonna make more power as rpm climbs while under full boost, its just midrange you are low/slow to spool.

You dont break 300rwhp till damn near 4,000 rpms so i can tell your not spooled all the way yet.

You have a nice power band for the track just gonna need a few tricks to get the car moving thats all.

 

[AbdullaGT500]

I'm curious if the hot rod cams and 4.10 gears have anything to do with it, thanks for the help man. I'm new to the whole turbo thing, I've always been more into blowers.

 

[TheKurgan]

Your torque should not be dropping that hard at 5300 rpms with the hot rod cams. Something is not right.

 

[JeremyH]

I'm curious if the hot rod cams and 4.10 gears have anything to do with it, thanks for the help man. I'm new to the whole turbo thing, I've always been more into blowers.

Yeah the hot rods are like anti-turbo cams lol, they have a very tight lsa which sucks for a turbo, you want 115-116. You would probably pick up power/torque going back to stock cams even.

Yes the 4.10s are definetly hurting, with some taller gears(lower numericly) you will move your power band, it will come on sooner as much as 500-1000rpms and be wider.

 

[TheKurgan]

Yeah the hot rods are like anti-turbo cams lol, they have a very tight lsa which sucks for a turbo, you want 115-116. You would probably pick up power/torque going back to stock cams even.

The hot rod cams are profiled to work higher in the rpm band than stock and you would not pick up power going back to stock cams unless you're going for torque under the curve.

 

[AbdullaGT500]

Oh and I forgot to mention, I can definitely feel the clutch starting to lose it's grab driving on the street. Once I hit around 4500-5000 it starts to slip up, not like it completely lets go, but you can feel it slipping, as if the tires were spinning slightly, except in 3rd/4th gear. I haven't beaten on it much yet, as I'm still getting used to the power. It is still on the stock clutch with 55k miles.

 

[JeremyH]

The hot rod cams are profiled to work higher in the rpm band than stock and you would not pick up power going back to stock cams unless you're going for torque under the curve.

N/a yes, not with a turbo, the lsa on those cams is restricting flow/boost up top.

The wategate operates off boost pressure and once at full spool as the rpms climb the pressure is getting held up by the cams at the head, the boost stays the same, but less flow, so you loose power.

You'd be suprised, the stock cams work great with boost.

 

[JeremyH]

Oh and I forgot to mention, I can definitely feel the clutch starting to lose it's grab driving on the street. Once I hit around 4500-5000 it starts to slip up, not like it completely lets go, but you can feel it slipping, as if the tires were spinning slightly, except in 3rd/4th gear. I haven't beaten on it much yet, as I'm still getting used to the power. It is still on the stock clutch with 55k miles.

Put it in 5th and slow down to around 45mph and hit it, that will let you know for sure if you are slipping.

Either way sounds like time for an upgrade!

 

[AbdullaGT500]

I'm ordering an exedy mach 500 today or tomorrow. I'm planning on getting 3.55's put back in instead of the 4.10's, and I may put the stock cams back in or get some cams that are more turbo friendly.

 

[JeremyH]

I'm ordering an exedy mach 500 today or tomorrow. I'm planning on getting 3.55's put back in instead of the 4.10's, and I may put the stock cams back in or get some cams that are more turbo friendly.

I would put the stockers back in unless you plan to upgrade valves springs, the 127300 is a beautiful cam for boost!

The car will be faster with 3.55s all day long!

 

[ondabumper]

Make sure all your pipes are not leaking on the hot side. This has happened to me. While the car is running, put your hand close to every pipe from the header to the turbine of the turbo and make sure you dont feel any air coming out. There could be a small leak and it will act as if there is a wastegate there.
Those Hot rods are hurting you. As far as Lobe separation (LSA) is the angle between the centerline of the intake and exhaust lobes measured in camshaft rotation. LSA along with duration and lift determine the amount of overlap that a cam has. A cam with a lower LSA will give more overlap with a given duration. By the same, increasing duration with a given LSA will also increase overlap. For turbocharger applications, an LSA between 114° and 117° seems to work well. Those hot rod cams have a 110 LSA. They also have a duration of 221 intake and 240 exhaust which gives a nice lope, but keeps the intake an exhaust valves open together too long.

 

[AbdullaGT500]

I'm having everything checked over next week when I get the new clutch in. I'm planning on putting the stock cams in along with 3.55 gears and im sure I'll need a retune after that.

 

[AbdullaGT500]

Forgot to add, I appreciate all the help guys!

 

[JeremyH]

Good luck

Make sure you overlay the new graph over the old!