Performer vs Performer RPM Which is better?

[meangreen92lx]

Hey all. I have a 1992 LX hatchback with a DSS 308, AFR 165's 58cc, FTI cam, Performer intake with ported lower, 70mm T-body, 80mm Maf, 1 5/8 longtubes, prochamber mid pipe, mac catback, 5 speed, 4.10's, etc etc etc. I had the car dyno'd the other day and it's putting down 311rwhp and 338rwtq. I think theres a little more to be had. The torque hits early like 300pdft at 2900rpm and holds 300 to 5500rpm. I was thinking of making the switch to the RPM upper to shift the powerband a hair higher. Does anyone have any real world experience on how much this switch would affect my lower end and upper end? I know I would probably gain some torque and horsepower above 5000rpm, but how much would I lose on the low end if any? Would it be worth it? Thanks

 

[meangreen92lx]

No ones ever swapped these??

 

[nvrenuff]

I swapped from a Performer to a TFS Track Heat which obviously isn't exactly the same bus similar none the less in terms of upping the power band. Mine is a very similar 306 combo (with some exceptions) and puts out about the same HP. I picked up about 3mph in the 1/4 going to the Track Heat, didn't notice any loss of low end torque, I have 4.10's though, so low end torque isn't really a concern of mine. I asked the same thing of the Performer RPM a couple years back, but got no answer either.

 

[N8Miller]

afr heads should NOT have less than an RPM intake!

 

[meangreen92lx]

Thanks for the replies. I'm not seeing a whole lot of downside to this. I am planning on taking the car back to the dyno after the swap to see if theres an improvement.

 

[Grn92LX]

Ask Ed what he thinks. An rpm upper sounds like a very smart move though. Back when I had my 302 I asked Ed his thoughts on switching to a different manifold (I had a trickflow streat heat) Ed said to go with an rpm manifold and a 75mm tb.

Have you ever ran it at the track?

 

[WLDHRSE]

I'll be looking forward to those results. I run a Performer, 70 mm Acufab TB, 75 mm Pro-M, Crane 1.7 Cobra roller rockers, and full exhaust on my 93 GT. I'm sticking with the stock cam though. I'm going to drop a set of AFR 165's on this engine if I don't find a buyer for the car. I was planning to stay with the base Performer intake but could be swayed by your results.

Cliff

 

[meangreen92lx]

Ask Ed what he thinks. An rpm upper sounds like a very smart move though. Back when I had my 302 I asked Ed his thoughts on switching to a different manifold (I had a trickflow streat heat) Ed said to go with an rpm manifold and a 75mm tb.

Have you ever ran it at the track?

I asked Ed when I first put this combo together and he said Performer. But since then, I've noticed my cam is a little bigger than most of the other similar combo's I've seen. I also have a fox body where most of the other cars are the 94-95 years. I've done extensive research into this and have found either a small loss of torque/horsepower in the lower RPM's (or none in some cases) and a good gain everywhere past 5000rpms. I have not ran it at the track yet. I've been busy getting everything up to where I want it first. I'll find out first hand how the swap works. Nice car by the way. I have the same thing.

 

[5spd GT]

afr heads should NOT have less than an RPM intake!

Tell that to Ed...

He told me the Performer has a more useable powerband over the RPM. But then again this is a daily driven car...

 

[tmoss]

Either one needs the lower worked to flow with the AFR heads, but I've suggested for years to get both - run the long runner Performer on the street and swap out to the RPM upper at the track or on Saturday night for some hunting

 

[meangreen92lx]

Either one needs the lower worked to flow with the AFR heads, but I've suggested for years to get both - run the long runner Performer on the street and swap out to the RPM upper at the track or on Saturday night for some hunting

Now that you've ported the lower, I can mix and match. The RPM upper is on it's way. I'm going to clean up the ports myself a little and put her on next weekend. Try to get it dyno'd again soon to get some real world numbers. I have a feeling the RPM will be staying on for some time though.

 

[352Ford2]

Does anyone have layed out the exact diffrences between the RPM and std performer?

My guess would be runner length, but how much is the RPM shorter?

plenum volume diffrences?

 

[tmoss]

Make sure you open up the pinch point in that RPM upper just above the flange to the lower. The "CNC" match is a joke - you should have no problem seeing where the material needs to be removed.

The RPM I upper is about 1" shorter than the Performer upper. Never cc'd the plenum to compare.

 

[meangreen92lx]

Make sure you open up the pinch point in that RPM upper just above the flange to the lower. The "CNC" match is a joke - you should have no problem seeing where the material needs to be removed.

The RPM I upper is about 1" shorter than the Performer upper. Never cc'd the plenum to compare.

Yeah, I did the same thing on my Performer upper while I had it apart for you to port the lower. The cnc match is a joke. There is alot of smoothing to be done just inside the ports.

 

[fidstang]

I would like to see the BBk SSI 5.0 intake ported on a 306. It's said to be better then a ported cobra out the box. Anyone running one?

 

[tmoss]

I would like to see the BBk SSI 5.0 intake ported on a 306. It's said to be better then a ported cobra out the box. Anyone running one?

You can't generalize based on one test on E7 heads in my humble opinion.

 

[fidstang]

You can't generalize based on one test on E7 heads in my humble opinion.

They're tested in the Muscle Mustangs and Fast Fords June 06 issue. They were ported E7's. But yeah I agree it doesn't show a true story of the power potential. That's why I was wondering what they would it would do ported on a real motor with AC and good aluminum heads. Know anyone running one? I want to know what they think, if they're worth it?

 

[tmoss]

I had a potential deal to trade porting a Cobra lower for a SSI unit but it never came to pass. Still haven't got my hands on one to inspect/measure yet.