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FI-Racing
Dodge Dakota
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10/08/2003
06:33:06
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 Subject: Project 2.5 liter turbo...
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Hello.. I own a performance shop in Southern Louisiana (www.forcedinductionracing.com). We specialize in Nissan Performance.. but my buddy and I were recently kicking around the idea of turboing his 2.5 liter Dakota. Here's our plan..
8.5:1 pistons
Forged rods
cam
Springs/retainers
head studs/main studs
ported head
GT3540 ballbearing turbo
Tig welded schedule 40 log manifold
3" downpipe and exhaust
Tial 38mm wastegate
HKS SSQ blow off valve
MSD 72lb injectors
Electromotive TEC III stand alone
Walbro 255lph pump
Spearco bar and plate intercooler
2" and 2.5" intercooler piping
Greddy Profec B
We're looking at making around 450-500whp at 20-25psi on the built motor. I've built a lot of turbo cars.. and with his displacement, with a good cam and head porting job.. and the big turbo.. he should get those numbers pretty easily. I was looking around, but didn't realy find much on forged internals for this motor.. or camshafts.. does anyone know of anyone that makes this stuff. If not.. we can have it made.. but it's nice to have stuff made already. Thanks
Travis Burelle
www.forcedinductionracing.com
www.fi-r.com
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BradC
Dodge Dakota
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10/08/2003
16:57:33
| RE: Project 2.5 liter turbo...
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What Year is the Dakota? Is it the jeep 2.5 or chrysler 2.5?
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FI-Racing
Dodge Dakota
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10/08/2003
21:45:19
| RE: Project 2.5 liter turbo...
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it is a 2000. im looking to see if any one makes inturnals for this motor. its the jeep motor.
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Brad
Dodge Dakota
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10/08/2003
22:22:51
| RE: Project 2.5 liter turbo...
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There are many parts that interchange with the 4.0l jeep 6 cyl. Basically the same engine with fewer cylinders. Mopar Performance has rods and Keith Black has some pistons for them. Don't know on cranks.
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FI-Racing
Dodge Dakota
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10/08/2003
23:16:08
| RE: Project 2.5 liter turbo...
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I know that Keith Black makes Hyperutectic pistons... do they also make forged slugs as well? I'll check into it and see what we can find. Thanks for the input guys..
Travis
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.alex.
Dodge Dakota
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10/09/2003
11:47:06
| RE: Project 2.5 liter turbo...
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Check with Kammer & Kammer Racing & McCormack Motorsports. They run a truck in the NHRA Sportsman classes that's a 4-cyl. It runs 15.3's and sounds like a really pissed off weedeater. I know that at least Kammer has a website, but I am not sure of the link....
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RAT
Dodge Dakota
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10/10/2003
01:52:40
| RE: Project 2.5 liter turbo...
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I'll tell you what man. If you can get about 450hp to the wheels with the 2.5l you could really make me happy. I have the I4 and I am trying to find out how to turbo it, I don't think I need 450 and horses but 300 would sure be nice, I would like to talk to you guys in how to do that if I could. See, I couldn't find anywhere to get a header made or even help me find out a way to make this possible. I know they make the supercharger kits for the jeep, wich would fit my truck; but I don't have about 4 grand lying around. Even if I cant do it I would really like to hear the progress you guys make. Best of luck to you,
Justin
JustinHinton@hotmail.com
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kota on 20s
GenIII
10/10/2003
02:11:02
| RE: Project 2.5 liter turbo...
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why build up a 4banger for a truck? it takes torque to move the brick, if you are planning on running a big turbo with a lot of boost, you will have to run a verry low CR, which will give up all lowend (didnt have much to start with) and have some turbo lag added onto that.
what RPM is it going to have to turn to put down these kind of numbers?
what are you going to do to the trans to keep it in one piece?
~Eric
Single cam, non-VTEC
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.alex.
Dodge Dakota
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10/10/2003
19:45:59
| RE: Project 2.5 liter turbo...
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Think in terms of cool-factor. A really light-weight, moderate powered truck that will handle, and get good gas mileage. Could be a good Auto-Crosser.
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FI-Racing
Dodge Dakota
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10/10/2003
20:42:57
| RE: Project 2.5 liter turbo...
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You're right.. torque is needed to get the "brick" moving.. Let's break down how low end TQ is made.. Two main factors that contribute to where the engine's powerband is.. are:
Bore size
Stroke
Also.. camshaft design and port design are important too..
Bore size is pretty much a no-brainer.. bigger bore=bigger displacement=more power.
Stroke and rod-stroke ratio dictate what the piston's speed will be, and has the biggest affect on powerband. A motor with a big stroke will make a lot of low end TQ.. such as the case with this motor. The bigger stroke with a rod ratio in the 1.40:1-1.50:1 range will make gobs of low end TQ.. because the piston gets up to speed much faster.. which increase low end Volumetric Efficiency (or... how well the cylinders fill with air when the piston is drawn down the bore. However.. this usually makes for a low redline, and decreased VE at high RPM.. this is why the 2.5 in the Dakota has a low RPM rev limit. Now.. we've covered the bore/stroke issue..
Now... if VE is good at low RPM, we have good TQ.. Now, what if we were to cram assloads of CFM into the engine at those low RPM. The engine would essentially have the amount of air flowing through it that you guy's big V8's draw N/A. Anyone knows that an internal combustion engine is a big "air pump" The more air and fuel you get in.. and exhaust you get out.. the more power you make. So, you modify the camshaft, and cylinder head to allow more CFM to flow though it.. and exhaust for it to get out. When in boost.. you now have an engine the flows as much or more CFM as a big 8 cylinder.
Another thing.. is people crying about turbo lag. Big displacement engines spool up turbos very fast. He will hit full boost by about 2500rpm or so. So, from 2500 to redline.. you will have a badass powerband.
So.. to sum it all up.. the 2.5 will be torquey enough to fry the tires at about 2500rpm, and get the "brick" moving on some slicks. And with around 450-500whp on tap.. with about 375-400 ft lbs at the wheels.. I'd say that you'd have to have a pretty heavily modified V8 to keep up. Plus.. with the 500 or so pound weight advantage.. that will give him an even better advantage. We could do a built V8 with a blower on it.. but in reality.. that would cost damn near the same to do what he's doing now. Plus.. I don't think anyone's ever done one of these before. I think it'll rock out..
Travis
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Vigo
Dodge Dakota
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10/10/2003
22:00:46
| RE: Project 2.5 liter turbo...
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im no expert on the jeep 2.5, but if it has bore/stroke dimensions similar to the 2.5 chrysler engine, you will make assloads of torque. its very typical for turbo dodge owners with the 2.5 to make, say, 220hp and 330lb ft of torque on around 15 psi of boost if it is tuned right.
however the low hp number is mostly due to the inefficiency of the stock chrysler 8 valve head.
dohc setups like the lotus head r/t engine and the neon head hybrids have been known to make MUCH more hp, as well as torque, at any given boost level. one car in particular, with a chrysler 2.5 bottom end and a dohc neon head on it, made 332 hp and 498lb ft at *2600rpm* on 16 psi.
point being, with such a long stroke, and a fast spooling turbo and low rpm powerband, you will be on boost almost instantly and able to make a ton of torque with relatively little boost.
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FI-Racing
Dodge Dakota
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10/10/2003
22:35:17
| RE: Project 2.5 liter turbo...
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Correct.. the 8 valve head limits that engine.. Turbo, camshaft, and head porting can do a lot for it though. A lot of guys that make high TQ numbers like that are probably pushing the turbocharger past it's peak efficiency point.. and blowing hot air up top. Turbos like that will spool up fast, and make assloads of TQ because they're instantly in their efficiency island (sweet spot).. but then as the RPM goes up.. it overspins the compressor and efficiency flies way off of the chart. I will probably tinker around with a few different compressor maps until I find one that maps out well on this engine. Also.. with a port job from Don over at www.polkperformance.com, and a good camshaft with high lift, a lot of duration, and no overlap, we should do pretty well. I'm predicting around 475whp and 400 ft lbs at peak. And TQ will hover in the upper 300's for a big part of the powerband. I wonder if it's possible to fit a DOHC head from the Neon or stratus motor onto this thing.. I doubt it..
Travis
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kota on 20s
GenIII
10/11/2003
00:42:54
| RE: Project 2.5 liter turbo...
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i understand what you are saying... but why build a 4 banger turbo engine for a truck? the thing weighs 4000 lbs or more. its not a civic or some econo box.
instead of cramming a lot of air into 4 holes, why not cram the same amount of air into 8? you torque would probably triple. and it would spool the turbo up faster.
~Eric
Single cam, non-VTEC
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Brad
Dodge Dakota
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10/11/2003
11:14:23
| RE: Project 2.5 liter turbo...
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I think it would be cool to see a turbo 4 with the possiblity of beating a lightning. And besides, it's different. Isn't that what Dodge is all about?
Only question I have, What tranny are you going to put behind that engine? The stock one would gernade at the first hint of boost.
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kota on 20s
GenIII
10/11/2003
12:03:40
| RE: Project 2.5 liter turbo...
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but why spend all of that money and R&D on a 4 banger??
if you can get 450-500whp out of a 4cyl with 15lbs of boost, you could probably get 700-800 whp with 15lbs out of a V8
~Eric
Single cam, non-VTEC
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FI-Racing
Dodge Dakota
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10/11/2003
17:58:11
| RE: Project 2.5 liter turbo...
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Well.. it would cost a lot more to source a V8, then completely build it up. Also, you're looking at getting all the stuff to swap it over to the V8 in the 4 banger chassis. Suspension changes in the front, mounts, tranny.. etc.. Then, you would need twice as much parts. Injectors, pistons, rods, bigger turbo.. Plus, I think turboing the 4 will be nice, and he's not realy looking for 800hp or anything. That's not very streetable. What tranny is in the 4 cylinder truck? I was assuming that it was of the same build up as the other Dakota tranny with just a different bell housing.
Travis
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03GraphiteJ
Dodge Dakota
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10/11/2003
18:56:09
| RE: Project 2.5 liter turbo...
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Why build up a 2.5? It's original for one. Might not do 10's in the quarter, but it would be damn cool I think. It's true there's no replacement for displacement, but that not the only way to make power. Big N/A V8, Turbo V6 or I4, it's all good.
And if that's what they wanna do, then I say go for broke!!
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Brad
Dodge Dakota
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10/11/2003
21:11:05
| RE: Project 2.5 liter turbo...
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Like I said Dodge:Different.
I think it's a pretty wimpy tranny.
Might want to source one from a jeep tj with the 4.0L six. They will have the same bellhousing.
I'd really like to see what kind of power that puppy will make.
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kota on 20s
GenIII
10/12/2003
03:09:01
| RE: Project 2.5 liter turbo...
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the trans is probably a AX15
<<<"Plus, I think turboing the 4 will be nice, and he's not realy looking for 800hp or anything. That's not very streetable"
and you think a 450HP 4banger with a standalone CPU is??? LOL....ok.
also, while you have the trans out, you may as well switch out the 8 1/4" rearend for the 9 1/4.
maby your buddy should have paid the extra $450 for the V8 option... would have saved him a ton of cash in the long run.
do any of you know if the 4 cylender engines are plegued with the crappy head bolt design as the V6's and V8's?
if so, i would think twice before running that much boost.
~Eric
Single cam, non-VTEC
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kota on 20s
GenIII
10/12/2003
12:18:33
| RE: Project 2.5 liter turbo...
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something i missed you said.....
"I wonder if it's possible to fit a DOHC head from the Neon or stratus motor onto this thing.. I doubt it.."
hell no it won't fit! the stock motor is a pushrod motor. not a SOHC OR DOHC.. even if the head bolted on the engine, WHAT THE FALK ARE YOU GOING TO DO WITH THE STOCK CAM??? i would love to see how that works. LMAO
you sure you have the knowledge to tackle this project....??
~Eric
Single cam, non-VTEC
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FI-Racing
Dodge Dakota
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10/12/2003
20:51:53
| RE: Project 2.5 liter turbo...
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Well.. I'd like to think that I'm a pretty reasonable guy.. and I don't usually stoop to insulting others. But it looks like some people on here don't do the same. I guess there's a few on any board..
First off.. I never said that the head would fit.. I merely asked. Why do you say that it wouldn't fit though? A custom chain, gears and guides... It might.. it might not. Personally.. I've never even looked at one of these engines, so no, I don't have any past knowledge on them. However, I do have a lot of turbo 4 cylinder experience.. Allow me to show you a little of it..
[img]http://www.fi-r.com/Adam%20Cremers_Lincoln_Nebraska.jpg[/img]
First ever SE-R Spec V turbo car.. and I also sell a full bolt on turbo kit for the cars.. a first and only also. Here's the dyno chart.. this is at 7.5psi
[img]http://www.fi-r.com/High%20Boost%20Dyno%20Chart.jpg[/img]
Here's another..
[img]http://www.fi-r.com/FI-R%20shop%20car_Houma_LA.jpg[/img]
Here's my wife's daily driver 404whp B15 sentra. This was 2 years ago.. and was the first B15 to break the 400whp mark.. and also the first to go 11's in the 1/4 mile. 11.73 @ 124mph on 22x8 slicks and C16. It also has a Speed Pro stand alone.. and it drives daily with no problems.
[img]http://www.fi-r.com/Erich%20Tucker_Phoenix_AZ.jpg[/img]
385whp 200sx SE-R
[img]http://www.fi-r.com/Dionscardone2.jpg[/img]
500whp SE-R Spec V.. fully built motor with Electromotive TEC II stand alone, cams, pistons/rods, sleeves, studs.. First ever Spec V to make that kind of power.. everything in this motor was prototype and custom made.
So, I hope that proves my credentials... I wouldn't take on a project like this unless I knew what I was doing. Also, the factory head bolts would be replaced with studs of course.. We'll address the drivetrain issues as the come.. I need to do more research into what the truck has in it and see what needs to be upgraded. Also.. why do you say that stand alone powered cars can't be driven daily? With new advances in fuel injection technology, there are tons of stand alones out there that will function daily with no problems. Electromotive, Motec, SpeedPro.. all produce fully functional units with GPO's to run fans, A/C compressor and idle control.
Travis
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