Interest in 3.0 Plenum Spacers?

[mightymulhern]

All,

There seems to be some growing interest in plenum spacers so Ed and I are talking about doing a run of them. The bigger the batch the less expensive they would be. Our target would probably be around $100 for a set including the bolts. The questions would be:

1. How many people are really interested in them?
2. How thick should we make them?

Ideally, we should make them thick enough to make flipping the upper plenum around possible, but thin enough to make sure that the hood closes. My guess would be 5/8", 3/4", or maybe 7/8".

If there's a lot of interest, we're ready to hit the go button. If there isn't any, we may hit it anyway and get some of our cars. Let us know!

[jory]

I'd be interested if they were available. 3/4" sounds good, I'm pretty sure there is enough room under the hood for that.

[92lebaronGTC]

5/8" or 3/4" sounds beautiful and should fit, I have 1/2" ones on my GTC with no clearance issues at all, there's still some room so something slightly thicker than mine would be perfect. I wish mine came with bolts, I managed to find ones at home depot that fit though, use METRIC THREADS!

They made a good difference on my car and my plenum stays a lot cooler all the time, I suggest getting them!

[NA2ndgen]

My 7/8" ones caused no clearance issues, on my 95 Caravan anyway, and in fact I am pretty sure still I have another 1/2" of clearance.

Just my opinion. But I think the main benefit spacers offer, is a slight increase in intake air velocity, from taking that sharp bend out and lengthening the runners.

DISCLAIMER

The above is merely the authors personal opinion and is not offered as a statement of fact. The author acknowledges their less than comprehensive knowledge and is open to correction presented in a non rude and abusive assholish way.

[mightymulhern]

Quote:

Originally Posted by NA2ndgen My 7/8" ones caused no clearance issues, on my 95 Caravan anyway, and in fact I am pretty sure still I have another 1/2" of clearance.

I'm surprised you don't have more room in a minivan. I haven't spent much time looking under the hoods of the vans, but I figured there were several inches available there.

Long ago, I thought I read that 1" would fit under some cars but not others. ...might have been old style Daytonas vs the 92+ style. Unfortunately I don't recall exactly.

Quote:

Originally Posted by NA2ndgen Just my opinion. But I think the main benefit spacers offer, is a slight increase in intake air velocity, from taking that sharp bend out and lengthening the runners.

Sounds plausible. Widening the turn would be a good thing. In addition it should keep the upper plenum cooler leading to colder air being sucked into the heads.

[mwinkle353]

I'd be interested in a set. Prefer the thickest available. 1" would be perfect. But I'll go for the 7/8" units, if that's what's available.

What material are you going to use for these units?

I honestly would use a good set of aluminum ones. Delrin would be my second choice. But if you are planning on useing Phenolic material, I'm not even going to bother with placing an order.

[m90daytona]

just out of curiosity, the plenum spacers add more torque but decrease horsepower right? i know w/ the 4th gen maxima, one of the trick mods is to take the 5th gen intake manifold off and bolt it on the 4th gen motor. its a variable intake manifold which means below 4k the manifold has long intake runners for torque and then an rpm switch closes a valve which shortens the intake runners giving the car 32 hp and lengthening the hp peak from 5k to 6500k. even the forced induction guys make more hp w/ this mod compared to the stock intake manifold.

my question is since our cars already make a ton of torque, but dont really peak so well stock, wouldnt we be better off w/out this mod?

[Ondonti]

the spacers make it easier to turbocharge the car. flipping the intake in reverse saves a lot of headaches.

A P body cant not use a 1" spacer.
Barely clears on an AA body. I had to remove a little bit of my hood cause the spacers rubbed in the past.

[mwinkle353]

Quote:

Originally Posted by m90daytona just out of curiosity, the plenum spacers add more torque but decrease horsepower right? i know w/ the 4th gen maxima, one of the trick mods is to take the 5th gen intake manifold off and bolt it on the 4th gen motor. its a variable intake manifold which means below 4k the manifold has long intake runners for torque and then an rpm switch closes a valve which shortens the intake runners giving the car 32 hp and lengthening the hp peak from 5k to 6500k. even the forced induction guys make more hp w/ this mod compared to the stock intake manifold. my question is since our cars already make a ton of torque, but dont really peak so well stock, wouldnt we be better off w/out this mod?

Horse power wins bragging rights. Torque wins races.


And if you think you have too much torque, then you have traction problems!!!!

[m90daytona]

Quote:

Originally Posted by mwinkle353 Horse power wins bragging rights. Torque wins races. And if you think you have too much torque, then you have traction problems!!!!

tell that to the guys running top fuel dragsters making 5500hp and running 4 second 1/4 mile times. or the supras/tt vipers running 8's making 1400whp. fact of the matter is you spend more time taching between 5k and 8k (depending on the car) in a drag race and torque numbers start to die off between 3k and 5k. in an ideal situation, you would have a "torquey" car for good 60' foot times but high revving hp for fast 1/4 mile runs and trap speeds.

top fuel dragsters peak around 9k, 1400whp supras peak between 8k-9k and indy cars somewhere around 10,000 rpms. indy cars usually make around 700hp and only 300 ft/lbs torque. my guess is if you reversed those numbers, the car wouldnt be nearly as fast. and i dont even want to start on bikes.

[mightymulhern]

Quote:

Originally Posted by mwinkle353 What material are you going to use for these units? I honestly would use a good set of aluminum ones. Delrin would be my second choice. But if you are planning on useing Phenolic material, I'm not even going to bother with placing an order.

Aluminum wouldn't insulate the upper plenum at all from the heat of the lower. I don't know how big of a differnece that makes, but we ruled out aluminum on first thought because of that.

Currently we're looking at a cast Nylon material. It has similar properties to delrin but a better working temperature range and acts as a better insulator.

[NA2ndgen]

Quote:

Originally Posted by mightymulhern I'm surprised you don't have more room in a minivan. I haven't spent much time looking under the hoods of the vans, but I figured there were several inches available there. Long ago, I thought I read that 1" would fit under some cars but not others. ...might have been old style Daytonas vs the 92+ style. Unfortunately I don't recall exactly.

I prolly do have more room than that. I didn't do the 'squish the clay test', and I thought 7/8" would be about right for my needs. I didn't want to loose too much on the highway at higher rpms. I just needed a little more power lower down. I should take em off, and see how she feels now with the ram air and all.

Quote:

Originally Posted by mightymulhern Sounds plausible. Widening the turn would be a good thing. In addition it should keep the upper plenum cooler leading to colder air being sucked into the heads.

My spacers are aluminum. But I had my lower intake, spacers, plenum and 52mm throttle body, all heat transfer coated outside and ceramic sealed inside. She runs better in hot weather than she used too, and in colder weather she runs even better. The cowl inducted ram air didn't hurt either.

[Ondonti]

Quote:

Originally Posted by m90daytona tell that to the guys running top fuel dragsters making 5500hp and running 4 second 1/4 mile times. or the supras/tt vipers running 8's making 1400whp. fact of the matter is you spend more time taching between 5k and 8k (depending on the car) in a drag race and torque numbers start to die off between 3k and 5k. in an ideal situation, you would have a "torquey" car for good 60' foot times but high revving hp for fast 1/4 mile runs and trap speeds. top fuel dragsters peak around 9k, 1400whp supras peak between 8k-9k and indy cars somewhere around 10,000 rpms. indy cars usually make around 700hp and only 300 ft/lbs torque. my guess is if you reversed those numbers, the car wouldnt be nearly as fast. and i dont even want to start on bikes.

torque #"s dont die off at 3-5k when you make your peak hp at 5-8K.

torque doesnt = good 60' either.

the saying 'torque wins races' mostly refers to cars with more torque usuallyhaving wider powerbands. the car with the wider powerband and similar peak power will almost always dominate.

A well build supra has a good usable powerband. A poorly built supra = dyno queen.

ANyways, this thread is all in reference to our 3.0 not these other motors. We cant rev past 6000 rpms.

[m90daytona]

Quote:

Originally Posted by Ondonti torque #"s dont die off at 3-5k when you make your peak hp at 5-8K. torque doesnt = good 60' either. the saying 'torque wins races' mostly refers to cars with more torque usuallyhaving wider powerbands. the car with the wider powerband and similar peak power will almost always dominate. A well build supra has a good usable powerband. A poorly built supra = dyno queen. ANyways, this thread is all in reference to our 3.0 not these other motors. We cant rev past 6000 rpms.

here is the theory
http://mgcgti.clarkeandclarke.co.uk/Page28.html

you are entitled to your opinion but i asked the question in my first post and nobody has answered it.

is the spacer going to add or subtract horse power? if it adds, then maybe i will spring for one. my guess is it doesnt but nobody has been able to confirm either way. i feel satisfied w/ the amount of torque my car produces and would even be willing to sacrifice some if it would peak better but not the other way around.

btw brent, what where your peek torque numbers/rpm on your last turbo set-up?

[NA2ndgen]

Quote:

Originally Posted by m90daytona here is the theory http://mgcgti.clarkeandclarke.co.uk/Page28.html

That is way over my head. I hope taking that sharp bend out helped a little is all I can say. Oh, and I wish I could have a variable length intake runner plenum set-up like 3.0 Diamante's have. I think it's the Diamante's right?