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Blow thru turbo set up help.. 351w

12K views 5 replies 3 participants last post by  TurboS10 
#1 ·
ok heres the deal. im new to the blow thru set ups.. ive pieced together quite a few Fuel injected turbo set ups. im planning on building this 351w blow thru with two T4 turbos.. the motor is stock at the moment and ive made a little list to try and figure this all out. im not positve if its the right stuff i need so i may need some advice.

First off making the engine strong to make alot of HP.
will i need to get new rods and pistons? also what kind of headwork should be done. im planning on keeping the stock heads but im almost postive they will need to have work done to them.. what is the norm for this? i will be using cometic head gaskets.. also what cam grind should i get?

Next is fuel...
Im planning on a holley 750dp which would be set up for blow thru.. what FPR is recomended? and for the fuel pump i will definatly be using the aeromotive unit. is there anything else needed here?

And for the turbos.
I will be running two turbonetics T4's on custom manifolds. also two tial waste gates and still undecided on blow off valves at the moment. and two side mounted intercoolers.

i have some questions on how to set it all up. basically just the vaccum lines from the waste gates and blow off valves to the FPR etc? how do i plumb this all up? any write ups on it?

Sorry for writing a book here. thank you for any help.
 
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#2 ·
You will definately need good forged rods and pistons. A forged crank is no a bad idea. The heads are kindof up to you. They are about like an NA engine when it comes to power production, but there is a fair difference. The main thing to realize is with good flowing heads you can make more power with less boost. This helps with heat and fuel octane needs. The lower the boost you can run to meet your power goals the better. I am running Dart 230cc intake runner heads on my turbo engine. It makes alot of power at 11-12 psi.

You will probably want a cam similiar to what I am running. Mine is 230 dur. @ .050, .480 lift, 114 lsa. More lift is desirable on the intake, but without going to a custom cam that is hard to find.

Mallory and Aeromotive both have good boost reference FPR. As for plumbing, it is just about like you described. Wastegates and FPR are plumbed to top of the carb. BOV is plumbed on the bottom side.

Chris
 
#3 · (Edited)
351W turbo

You will definately need forged pistons. Hi performance rods would also be a big asset, however, your stock crank is quite beefy, and can easily take the boost, unless you are going extremely radical. On this point, I would recommend getting your entire reciprocating assembly dynamically balanced. This includes your crank, rods, pistons, rings, bearings, flywheel or flex plate, and harmonic balancer. Some balancers may even want the cam gear and key for the crank.
I would recommend going with aftermarket heads. Even though I am a Ford man, I have to admit that stock Winsor heads in any condition arent the best flowing in the world, no matter what you do to them.
As for heads, I would recommend the TFS Twisted Wedge heads, as they are the biggest bang for the buck. Other wise, unless you want to spend money on getting the pistons flycut for larger valves, stick with heads that have 1.90-1.94 intakes/1.60 exhaust valves.
As for a blow through carb, you will have to have the carb setup for this by having it modified for seals on the throttle shafts etc. Best to contact a carb company or one of the houses that deal with pressurized carbs on that issue.
As for intake, a Performer RPM or Performer RPM Air Gap, should do the trick.
As for the exhaust, I would consider running a good brand of shorty headers like BBK, and turn them upside down so that the turbos are mounted on top of the engine. This can be done by cutting out the bridges between the ports on the mounting flange. I would also recommend using ceramic coated headers for such a setup, as they will help keep the heat inside the exhaust system, giving better pressure to the turbos.
Since you are running dual turbos, you will want to run turbos that are designed for half the displacement of the engine, other wise you will wind up with serious lag problems at lower RPM.
Your camming is still dependent on the RPM range you plan to operate in.
If you are planning to build a stout low end power engine with lots of grunt off the line, you will want to stay with a cam in the 220-230 degree duration range in a hydraulic and a 230-240 degree in a solid lifter. Either cam will put you in the 2000-6000 RPM power band, which if this is a street engine, is quite adiquate. I would also recommend going with a dual pattern cam, as the added exhaust duration sure wont be a hinderance to your turbos.
I have gotten custom ground cams from Camresearch, in Englewood, Colorado, and am quite happy with their work, and they also have a machine that will lap in your cam and lifters for you, so you dont have to mess with cam breakin when you first light off the engine. Another plus to Camresearch is they are Ford specialists, and they do a lot of R&D and utilize all the feedback they get from clients. And you can get a custom ground cam from them for about the same price as you will get an off the shelf cam from a major grinder.
I am also curious what kind of vehicle you are putting this engine in.
 
#4 ·
Intakes:

Turbo engines DO NOT like dual plane intakes. You definately need to go with a large open plenium intake. The rules change on some things with a turbo setup. Victor Jr. or similiar is what you are looking for. You need the large plenium and short runners on a boosted engine.

Cams:

You DO NOT want to run a typical split duration cam. They are all wrong for a turbo engine. If you want to run split duration, it needs to be like I described where it favors intake. This will increase heat and velocity of exhuast gases. Much different approach than NA, supercharged, or nitrous. Any custom cam manufacturor will know this. If they dont....RUN! Turbo cams should not have higher exhaust duration and lift. This is not to say the engine will not run and make good power, but it will certainly not be optimal.
Straight up cam profiles with wide lsa are the next best thing available off the shelf. If you go with a solid cam, you want to go down in duration and lift...not up. Solid cams are more efficient with more aggressive lobe profiles.

Chris
 
#5 ·
Well this is all good info... maybe i should go more indepth here.. im looking to get in the 700 to 800whp range with this. im assuming that is pretty fair.. or is it too much to ask? i am looking at the eagle H-beam rods.. i know these are recomended but are their any just as good or good enough for less money? and for pistons i was looking at sealed power forged. will these work decently? i was also thinking about getting the pistons coated for extra safety. im not looking for an insane amount of snap off the line im looking more towards the 3k and up rpm range since its not a drag car its more for the track so what would be a starting point with a cam? and i dont think i can use a set of stock headers since this is going into the back of a porsche 911. you guys are giving me good pointers, thanks
 
#6 ·
Doesnt sound out of the ordinary. That is my power goal with my engine. The main thing is that you need good flowing heads. You dont need a big cam to make big power with turbos. You can make 3HP/cid even with a small cam if you have the rest of the combo right. Always remember that turbo engines do not need big cams to make big power.

Also, buy some decent light wieght pistons like JE, Wiesco, SRP.....Speed Pros are cheap, but they are HEAVY.

Chris
 
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