88 350 tpi formula

iTrader: (9)

well, looks like I will be adding a 406 tpi to my car this winter. I will be picking up the 406 within a few days and going through it this winter making sure it is good. oh its a runner too, I plan on getting a lower intake and porting the heck out of it.

Grim Reaper

Unless you are really hung up on the looks of the TPI intake, dump it and get something more free flowing. The StealthRam and John Millican's modified LT1 intake at $400 are my two choices for "best bangs for the buck" when it comes to intakes.

I just swapped to a Miniram on a basically stock engine and I didn't loose ANY bottom end torque. It's all BS. This Miniram pulls better EVERYWHERE except a little softer from 3,000-3,500 rpm. And, right now, my eprom is "detuned" while I check out the install and optimize the fuel. Once that's done and I start to optimize the eprom, I expect the Miniram to beat the TPI in everyway.

Anyone who says you loose bottom end torque with a Miniram, never had one and don't know what they are talking about. I say this from actual experience on a basically stock engine.

Test King

I would unquestionable vote for the Stealthram over the Miniram/LT1 'vert intakes for all except the highest RPM motors. It's purely opinion, but...

Ever notice how the runners taper towards the intake port - jsut like the infamous T-Ram?

There is a less severe angle that the air has to turn to go from the plenum to runner, thus creating less friction in the air itself.

Larger plenum.

But those are just reasons for my opinions, and everyone will have diferent reasons for diferent intakes.

Grim Reaper

Have you ever seen the inside of a Miniram? It a long, narrow opening at the top of the "internal runner" (2.6 x 1.35 inches) that crosses over to the other side (like an "X" inside the plenum) and narrows down (to increase the velocity) down to the port opening of 1.96 x 1.20. Almost perfectly port matched to a Felpro #1256 (1.23 x 1.99) Intake Gasket.

It's a very efficient design to give high velocity and good flow. That is why there is actually a torque gain, not a loss at low rpm (so I have actually experienced). And it just screams after 4,500 rpm.

Lastly, it does change the note of the exhaust. My car now sounds more like an LT1 (for obvious reasons). In fact, that is the first thing that people have commented about my car, they though I changed the exhaust.

85350TX

How much did you pay to switch from TPI to Miniram? and what parts does that include?

Odyssey

You have to buy the Miniram manifold itself which is about 900 bucks, PLUS the fuel rail "kit" which is about 300 bucks. Pretty expensive compared to the stealthram or LT1 intake. Myself, I'm getting an LT1 intake

85350TX

so about 1200 for the guts and there is always odds and ends do you have to change anything with the prom or computer for this?

Test King

There is a reason that the Miniram/LT1 manifolds run a few cylinders leans and a few rich... and it all has to do with the bend the air has to make from the thorttle body opening into the closest and farthest runners. It's simply a fact... the more severe the angle, the greater frictional losses in flow, the less are that makes it into the port at any given point in time. All non-single plane EFI manifolds have this problem. TPI, LT1, MINIRAM, SuperRam, STEALTHRAM, and Ford's were almost as bad as the LT1/Miniram's in this respect because of the long path of travel the air had to make down the plenum, and the fact there was 2 90 degree bends (ref'ing to the 5L).

Point is, the Miniram/LT1 is a great manifold, and you won't lose your low end. You will loose a little between 2800-3400 RPM, and a very little way down low (Per' a Chevy High Perofrmance dyno battle between the L98/LT1/LS1), but it's still a good manifold almost everywhere else. I just happen to feel that the stealthram and superram both have fewer problems with flow friction from their plenum to port passages.... which is also why they tend to run all of the cylinders more evenly as far as air distribution. You can't beat the price of an LT1 conversion - I'm doing one..... but if I had a couple extra bucks, I'd use the stealthram instead.

And I have never actually had a miniram in my hands - I've seen pictures, and the same holds true...tiny plenum, IMMEDIATE bend into the first intake ports right from the throttle body opening. But I know this will turn into a "How dare you insult what I say newbie poster" type post if we continue this.... simply because you have money invested in something, and as with anyone, they HATE to accept the fact that it MAY not be the absolute best, or they are simply too "Bullheaded" to accept anything other than what they "Beleive."

Grim Reaper

Actually I did a LOT of investigation BEFORE I committed to purchasing my Miniram. I spent about 3 years investigation ALL the alternatives before I made my committment (I did buy used btw - I am no fool with my money). Had the modified LT1 been around when I made my purchase committment, I would have gone that route instead. So I am not "bullheaded" or afraid to give an "HONEST" opinion just because I have money invested in a Miniram.

As for the "rich vs lean" aspect, UNLESS you hook a WB O2 sensor on EVERY cylinder, there is no ACCURATE way to actually measure this. By looking at my spark plugs I am running VERY consistent from cylinder to cylinder. More consistent than my original TPI I should add.

But it is really a "mute" point, because you generally get a greater variation just from the injectors themselves. So it is a "lot of worrying over nothing" IMO. You can have greater variation from the Injectors themselves. Hell, most people's eproms are further away from the proper A/F ratio just than their variation. In fact, do you realize that the ECM makes all of it's fuel calcuations just from one bank of cylinders?

Lastly, have you ever tried to install a Superram? THAT is why I wouldn't even consider it. Also, it too is quite expensive when you ADD UP all the parts. Plus there are a number of people that found out the "lid" did not fit properly and suffered vacuum leaks. In all honesty, I would not want a Superram. When I make a modification it's to SIMPLIFY maintenance not make it MORE complex. The Superram was not even in my shortlist of intakes.

If I were to do it all over again, I would still go with the "one piece short runner intake", but probablly the modified LT1 instead of the Miniram. But I am still much happier with my Miniram than the other alternatives. I am still not sold on the StealthRam for a Firebird (which I own). I have yet to see anyone prove it clears the hood (though I suspect it can be done with fabrication). But then you loose your Strut Tower Brace (ditto for the Superram).

But, NONE are perfect. They all have their "advantages and disadvantages". I like the "ease of maintenance" of the Miniram/LT1 (R&R being a prime concern for me). The lack of potential vacuum leaks due to it's one piece design. But more importantly, the WIDE power band it delivers. The "myth" that you loose bottom end torque is completely false.

PS: I burn my own eproms, so the cost to "optimze" my eprom is nothing. Only rich people and/or fools buy an eprom. And if you get a StealthRam you MUST burn your own eprom. In spite of what those "custom eprom writers" may tell you, they DO NOT know the VE Characteristics of the StealthRam at this time (though I am sure that some of the better ones are working on it). They all work of "previous eproms" and, until they actually PLAY with a StealthRam, they won't know it's VE characteristics. Thus it's highly unlikely to get an optimal eprom if you buy one.

I think you are going to find a lot of people that "buy" an eprom for the StealthRam are going to run slower than they really should be.

Grim Reaper

I too would go with the modified LT1 intake. John Millican's charging $400 for it (intake included), which makes it one of the cheapest alternatives (other than just porting everything yourself, which won't get you the same results - though better than stock). There are some differences between the two, but IMO, the differences don't justify the cost.

I would use the money saved else where...like a nice set of heads.

Test King

I personally feel the superram is a joke. It suffers from the baseplate design of the TPI setup (Running across the entire width of the engine - the best way to heat up and slow down air), cost way too damn much, and as you said, installing is a PITA (Yes I have done it a few times on a buddies car - takes about an hour and a half if everything goes right.)
As far as the cylinder to cylinder air/fuel ratio - it becomes EXTREMELY IMPORTANT in nitrous applications. For a NA motor, under 10:5:1 compression, running at about 147:1 (I beleive) it is mute... add the pressurized gas, and it beomes your life blood to determain that there is eough air present for the fuel, and DEFINATELY that there is enough fuel pressent or the air in the cylinders that draw more in due to intake design flaws.

But like I said - I'm doing the LT1 swap because of the $$$ and I'm sic of the PITA TPI setup. The Stealth I believe is only a two piece assembly, but it's still about $100-$150 more expensive that what I will be spending on the LT1 (getting a free intake and fuel rail).

Grim Reaper

Good choice. As I said, had the modified LT1 been available before I made my committment to purchase the Miniram (I bought it used from a friend), I would have one too.

My appilcation is N/A, so it is not as critical to me. Yes, with power adders, then leaning is something to watch. But there are "fixes". Pity the 8051 ECM is not "directly" useable on a engine running the 165 or 730 ECM. The 8051 can actually "trim" individual injectors.

I have been diving into the 7730 code and it appears that "each bank" might be "trimable". If so, then it might be possible to re-wire the "banks" from "right and left" to "front and back". And then you just "trim" the fuel to compensate.

Also, if a guy was to dive deep into the 7730s code, it MAY be possible to wire an "input" to let the ECM know that you have NOx active. Then you could modify the ECM to automatically provide additional fuel if the NOx is active. The things you can do if you dive into the source code.

88 350 tpi formula

iTrader: (9)

I think for now I will keep the tpi and perhaps see how far I can cut the lower manifold. but, you guys are right I will break down and go for the lt1 or maybe there will be more

Test King

Well okay, that's your choice man, but let m just do some quick math here, ince there is no way you are goingto run a stock sized TPI setup on a 406 and expect ANY POWER above 4k.

Hand ported lower manifold - $30 in misc. grinding bits
Aftermarket Runners (Cheapest SLP) - $299 Approx.
TPI Gasket set - $20
Praying to *** that you don't have a cav. leak - Priceless

So we are talking $350 + Tax on a setup that won't make you nearly as happy as the $400 LT1 Manifold...

All assuming you don't FUBAR the base - add $300 just in case

Good luck on the TPI setup

88 350 tpi formula

iTrader: (9)

I already have the runners and bits, very long aluminum one too.