bwv505

Hi guys, I have been collecting parts to upgrade my setup and am getting close to starting the install. I am starting with a fresh 355 that has about 8000 miles on it, eagle balanced rotating assembly, 10:1 compression, stock heads and a regrind cam with .495 intake lift / dur @.050 .218 deg, .502 exhaust lift / dur @.050 .224 deg, 112 deg lobe separation with the stock rockers. It also currently has the stock tpi with original injectors that are dying.

I have some questions, the first being about the miniram I recently bought. It seems to be the old style without the air-gap between the runners. It also doesn't have anywhere to hook up vacuum lines. Has anyone on here had one of these, and what did you do for vacuum? I am not opposed to drilling and tapping the side of the manifold but would like to know if there was a better way. Also, does the old style intake require the small cap distributor? I have seen plenty of the later ones with the big cap setup but have only seen a couple pics of the old style, none of which included a distributor.

Here are some pics of my dinosaur intake:





http://s751.photobucket.com/albums/x...ANY0771.jpg%26

I am also adding a set of harland sharp 1.65 roller rockers, comp cams beehive springs, and 96 lt4 valve covers. Has anyone put these covers on an l98 and only used the single pcv port? Would it be wise to drill a hole in the other cover and run hoses from both valve covers?

Last but definitely not least, I have a procharger p600b kit with the dual intercoolers that will be going on after all the other stuff is sorted out. It should be a pretty entertaining driver when everything is done.. Any input will be greatly appreciated, thanks!!

bwv505

Does anyone know when the miniram came out with the air-gap version? It would be cool to get an idea on how old this intake actually is...

cv67

Youll notice no difference in power with the gap/no air gap its hot under the hood period. Dont know all the particluars on drilling/tapping shouldnt be a big deal though.

mgroshong

I don't believe that to be true, an aluminum intake manifold is just a huge heat sink and the more mass it has the more heat it will hold. why do you think people eliminate the coolant through the throttle bodies and run phenolic gaskets? It's certainly not to "add" heat to the intake manifold.

I have seen people talk about doing extended burnouts to get there intake as cool as they can and it has shaved some time. Now these were imports and had fully isolated intake manifolds. I haven't personally logged iat's but the theory is sound.

cv67

In an engine compartment with good airflow Id agree just seems on these C4s everything gets heat soaked period. Could be wrong though.
Guess what Im saying is would he notice the difference in his foot thinking not.

Scott S

How much time do you think the air spends in the intake manifold when the engine is at high power? I'd bet it's less than a second from the time the air enters the throttle body until it enters the clyinder at high power. How much heat can it absord in such a short amount of time?

Scott

mgroshong

It's not about hp at high rpm for sustained time, it's about driving down the road and punching it, and the iat will take longer to level off. If the intake manifold is a larger heat sink as would be with a none air gap style manifold.

If that's truly the case why does anyone plug the coolant lines to the throttle body and run phenolic gaskets? Why would companies make composite manifolds, it's all about reducing the amount of "potential' heat the air has to encounter.

vetteoz

To make the engine bay prettier.

Because on carb engines it slows down heat soak to the carb which boils the fuel in the bowls; not applicable to injected engines

mgroshong

please don't say iat's are not relative to fuel injected cars. and again unless you have logged iat's you can't say it doesn't matter. It's common practice with imports and you can go from not being able to touch the intake manifold to being able to rest your hand on it while working on the car.

Pwnage1337

I would give TPIS a call about the manifold vacuum. They used to make the product so they should have some idea. I can't believe they would ship a manifold without vacuum ports, since half of the car runs on vacuum. Cruise control, air conditioning, brakes. It would be stupid to make a manifold without vacuum nipples.

vetteoz

Read what I SAID.There is no fuel stored in open fuel bowls to evaporate on EFI cars
Go for a drive then touch ANYTHING connected to the engine.It will all be at SAME temp; having a insulator SOMEWHERE will have no effect on component temps.
As noted by cuisinartvette above ,C4 's get hot underhood; period

I have plenty of datalogs and my IAT temps stabilize and don't change until engine cold

Maybe ; BUT will are not dealing with them on this Forum

vetteoz

http://www.thirdgen.org/techboard/al...ml#post4646911

ddahlgren

If at WOT and it flows 250 cfm then flows 4.166 CF per second measure the volume even outside dimensions close enough to give a rough idea..

383vett

Back to the op's question, go ahead and drill and tap the plenum for vacuum ports. It won't hurt anything. Maybe you got a hold of a prototype without production ports. And just my .02, Chuck the regrind cam (they are not that expensive) and get a stick with some lift. Your motor will like it, especially if you are going to put on the miniram.

bwv505

The cam will eventually get replaced, but currently I am trying to get the miniram and the procharger/intercooler setup on the car. I still have the origianl exhaust from the manifolds to the mufflers on it also, so exhaust will come before a cam as well.

Thanks for all the replies guys!!