Mike Marra
1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
Project Log:
http://www.turbo-mopar.com/forums/showthread.php?69708-The-Contraption-2013-14&highlight=
Can we PLEASE get Ken (5Digits) in this discussion!? PLEASE! The 1-piece was a GIANT compromise AND a mistake!! It cost less to produce, plain and simple. From the shredded bits of the story I've heard, the man that was in charge of designing the replacement for the 2-piece had a GREAT design. Something happened and he couldn't propose it. Somebody else had the design we all know as the 1-piece and it got chosen by default basically.
So, any thoughts that the 1-piece is a superior design because that's what was run later is false. It was mostly bean-counter politics.
You most certainly CAN sonically tune a pressurized intake! The speed of sound is based on temperature, NOT pressure. So, if you can predict an operational temperature range for the air inside the manifold, you most certainly can tune it!
I see two reasons to go from two piece to one. First, one less casting, and one less gasket means its that much cheaper. But from a performance standpoint, you also do not have to worry about the mismatch between the two castings being an issue.
I do not however see how it would be any cheaper to produce a one piece intake that would work any better or worse than another one piece, unless you are constrained by available space.
Mike Marra
1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
Project Log:
http://www.turbo-mopar.com/forums/showthread.php?69708-The-Contraption-2013-14&highlight=
I've compared the 1 piece and 2 piece back to back. When i got my 1st ShelbyZ I ripped off the 2 piece for my GLHT and wanted a 1 piece because somewhere way back before forums I had read the 1 piece was better for low end torque which the Daytona needed in spades. Also threw a ported exhaust manifold on the car too. Well I picked up the off-idle torque I wanted but the car didn't rev through the powerband as smoothly as it did before the swap. Got to thinking about it and went out and bought another 2 piece. Put it back on the car and all the smoothness was back. Car was nice and smooth up through the powerband. Didn't lose one bit of off-idle torque either.
Think you need to look at that Masi intake again, A 2 piece is so much more similar to it than a 1 piece. Big fat runners on both, Better plenums on both.
That's part of it.
Cheaper to make, Also easier to work on. Those are it. Working on a 2 piece is a pain in the butt compared to a 1 piece. A 1 piece is a Pile of crap that is barely adequate for 175hp. Read the 2.2/2.5 performance handbook. They freak out if you want to go above 14.7psi on your motor.
Marra got it right, thats a 1-piece. Similar to how FM mods them but they keep the top looking stock. The 1 piece is OK once the neck, plenum and runners are fixed
IIR Mechanics in the field complained about difficulty removing the fuel rail/injectors on the 2pc. Add to that cost, not having to assemble the 2-pc and commonality between TI and TII intake castings while only needing to support 175hp... it was probably an easy business decision for them and the 2-pc was available in the MP catalog for anyone who wanted one.
So, with the crappy stock 1-pc, who has gone the quickest on a stock unported 1pc? JoeDuno's van went 12.90's on on on motor and 12.50' with a hit. Stock, unported.
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Just look at the factory power ratings, that show's the difference and also how the 2 piece moved the torque up in the powerband.
As said, it was a compromise for cost, packaging and working on the vehicle.
It is but there are other factors. I've been reading alot on porting and the big guys say the same thing, a good n/a head is a great boosted head. No difference in mentality. Look inside a one piece, there is NO velocity, lol.
TIII intake has a small plenum and short runners, makes stupid power all over the rpm range.
Everything the OEM's produce is a compromise, they can't build a race car for the consumers otherwise it won't be driveable and warranty costs will skyrocket.
1989 FWD Turbo Caravan-2.5 TIII, GT35R, auto, a/c, cruise, pwr windows/locks, fully loaded with interior and ran with full exhaust. RETIRED FOR A FEW YEARS! 12.57@104 :O)
1984 Chev Getaway van, 6.2 Diesel with a remote mounted turbo setup burning WMO-For sale.
2003 GSW 2.0L TDI, auto, fully loaded, modified, 360K-wife's.
2004 GSW TDI, 5 speed, fully loaded, modified.
Aurora ignition wires for sale. Link to info
Super60 roller cams or custom/billet cams. Link to info
Where's the guy that owns them? He ought to know shouldn't he?
You mean one guy took a leave of absence and they kept a "botched" part in production for 6 model years?
You don't think perhaps that the design of the later manifolds didn't significantly impact performance and was deemed just fine for 175hp?
Anybody wonder that maybe it wasn't a very big deal to have an intake manifold with optimal sonic tuning if they were going to be choking it down with a 2 inch exhaust pipe?
Mike Marra
1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
Project Log:
http://www.turbo-mopar.com/forums/showthread.php?69708-The-Contraption-2013-14&highlight=
1989 FWD Turbo Caravan-2.5 TIII, GT35R, auto, a/c, cruise, pwr windows/locks, fully loaded with interior and ran with full exhaust. RETIRED FOR A FEW YEARS! 12.57@104 :O)
1984 Chev Getaway van, 6.2 Diesel with a remote mounted turbo setup burning WMO-For sale.
2003 GSW 2.0L TDI, auto, fully loaded, modified, 360K-wife's.
2004 GSW TDI, 5 speed, fully loaded, modified.
Aurora ignition wires for sale. Link to info
Super60 roller cams or custom/billet cams. Link to info
Mike Marra
1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
Project Log:
http://www.turbo-mopar.com/forums/showthread.php?69708-The-Contraption-2013-14&highlight=
Wow look what I missed. When I get on my computer later I will give some more insight
[SIGPIC][/SIGPIC]
So all we need is 27+psi to not have to deal with any of this making stuff flow good.. Sign me up for that!
MinivanRider
1989 FWD Turbo Caravan-2.5 TIII, GT35R, auto, a/c, cruise, pwr windows/locks, fully loaded with interior and ran with full exhaust. RETIRED FOR A FEW YEARS! 12.57@104 :O)
1984 Chev Getaway van, 6.2 Diesel with a remote mounted turbo setup burning WMO-For sale.
2003 GSW 2.0L TDI, auto, fully loaded, modified, 360K-wife's.
2004 GSW TDI, 5 speed, fully loaded, modified.
Aurora ignition wires for sale. Link to info
Super60 roller cams or custom/billet cams. Link to info
Guess what the super 60 package used?-The proper intake manifold to use is either the 1987 production Turbo II- unit or Mopar Performance's P4529100. This is a two-piece design that is significantly better than the 1988-89 one piece unit. A larger 52mm throttle body from a mini- van or later model 3.3 engine replaces the original 48mm part.
http://www.thedodgegarage.com/turbo_s60.html
Did someone say my name???
Yes I can shed some light. Both cars are getting engine rebuilds so I can answer. All the "good stuff" was put onto Mini and it did include an exhaust manifold that had most of the bump on cyl 3 removed. But it did not appear to be otherwise ported. (Now this is probably but not definitely the exhaust manifold that was on Slug for her record.) The 1 piece intakes on both cars were not ported or gasket matched at all for their respective record runs. And the other exhaust manifold was bone stock.
Mini even still sports not only the 2.5" swingvalve but a long 2.5" section of downpipe and a cat. (Although for her record she did not have a cat, to the best of my recollection.)
Both of Gus' racecars used a stock one piece intake as does my 91 Spirit ES. It managed a dyno of 268whp & 372 ft-lbs torque more than 10 years ago without even gasket matching and 25psi.
You can make plenty of hp by running high boost without all the typical machinework hp mods. That was Gus' entire point all those years ago.
However there is a place for all the work, progress, and tuning enhancements everyone has worked on since that time. And both rebuilds will take varying advantage of those which will be documented in the build/restoration thread.
-Wayne
Wayne H.
'91 Dodge Spirit ES 2.5L turbo 5spd
'05 PT GT 2.4T HO autostick (RIP)
'89 Plymouth Acclaim 2.5L turbo auto, "Slugmobile" yes, THE Slugmobile!
'89 Dodge Caravan SE 2.5L turbo auto, "Mean Mini" yes, Gus' Mean Mini! (Current best 11.699 @ 114.43 mph! - Oct 15th, 2022 Cecil County Dragway, MD)
MeanMini dragracing videos: https://www.youtube.com/playlist?lis...URZLB1RxGYF6vw
and other cars, trucks and motorcycles
https://www.youtube.com/user/SlugmobileMeanMini