Building a 10 second M90 powerplant

rallystang

Registered User
I have a new goal now of a 10 second M90 powerplant. I am planning on a 4.2L crank and forged internals. I will be running nitrous. I am wondering which blower to go with. I think I can achieve my goals with a ported 94 blower. I currently have a M90 from a 1990 and am going to upgrade. I figure I'll need ~550 RWHP to hit a high 10, I should be able to get 250 from the motor alone, another 150-200 with the blower, and 100-150 from nitrous. Would the MPIII be worth the cost here?
 
Last I heard the 4.2 crank is not forged, and its longer stroke will make your mains shoot out through the oil pan.
 
Why a blower? Say you plan to spin the blower to 15 psi. If you had a turbo at 15 psi on the same identical motor you'd have over 100 more RWHP. Have any idea how much parasitic drag the blower takes to spin?

Ported 94 blower and 10 second car.... not gonna happen. If you get it in a 3100-3200 lb. car you might be able to run 10's if you killer traction, and you'd need at least 430-440 rwhp at 3200 lbs. If you have your heart set on an M90 you'd need an MP3 since its the best option out there.

If you are just set on a blower but not necessarily a puny m90, think twin screw.... I bet it can be done with a 1.7L but with a 2.2L or 2.4L twin screw if you have big enough injectors and can flow the air through the engine the power will be there. 2.2L and 2.4L twin screws can put cobra's in the 9's so with 2 less cylinders to fill the 2.4L may be major over kill. Think about the pumping volume of a V6 vs. a V8, the two extra cylinders must be filled in the V8, so the V6 has less volume so it can make good power with the smaller blower. I would say you need a twin screw blower like a Kenne-Bell, Whipple, or Auto Rotor to make it into the 10's.

The only one I know who's probably going to break into the 10's with an M90 is Kevin Leitem, and his car is only about 3200 lbs possibly lighter. He has an MP3, 10:1 compression, and a good cam and great heads. Plus his car is set up for drag racing. He still drives it on the street but some of us probably wouldn't enjoy the car for a daily driver with it gutted. So far the only V6 MN-12 I know of to run into the 10 second range is Coy Miller with a lot of Nitrous and a severly ported M90 that is something between mp2-mp3 specs.

Check out Magnum Powers to see the port work on the MP3 it will give you an idea. No matter how well you get the M90 to flow, it still can't compare to a twin screw. It may come close to the 1.7L, but a 2.2L twin screw will outflow it by a large margin.
 
Thanks for the input. I am going with a roots blower, I understand efficiency just fine. There is a guy running 700HP from a 4.2L crank... They are stronger than many think. You guys think a SC crank is stronger? Yeah, my mustang is pretty light, and will only get lighter.

I know it will be a task, but I don't think it will be as tough as you guys are talking. A fully built/breathing motor alone will make 260HP, +blower +nitrous... 440 hp easy.
 
Darn.... guess we must be doing something majorly wrong with our SC's if its that easy to get 440rwhp out of our motors :eek:

Frit
 
You wont get 260rwhp all motor with an SC motor. best head available flows a little less than 230cfm and thats the best we have. I wouldn't be so optimistic, it's gonna take some time to figure out the right combo if you're shoot for that. It might even be enough of a challenge to have an AR make 550RWHP with nitrous. Maybe not though.

I spent a whole week on one port for an SC head from a junkyard and could only get 260cfm on a 3.831 bore. This is from cutting out the sidewalls and welding material back in. I also raised the port which is where i got most of the cfm wakeup. I could get more, but it was just too much work. Needless to say that someone would have be ready to pay $7,000 for a port job to get these numbers or better out of a head. This is an actual common price to pay anyways.
 
rallystang said:
Thanks for the input. I am going with a roots blower, I understand efficiency just fine. There is a guy running 700HP from a 4.2L crank... They are stronger than many think. You guys think a SC crank is stronger? Yeah, my mustang is pretty light, and will only get lighter.

I know it will be a task, but I don't think it will be as tough as you guys are talking. A fully built/breathing motor alone will make 260HP, +blower +nitrous... 440 hp easy.

450 rwhp with nitrous is very doable. With good heads, cam, fuel system, exhaust system, intercooler and a ported blower it's pretty common to get 350 rwhp...and you can get the rest using nitrous.

David
 
rallystang said:
Thanks for the input. I am going with a roots blower, I understand efficiency just fine. There is a guy running 700HP from a 4.2L crank... They are stronger than many think.

Just to remind you, a roots blower makes it's power in a different way than any other power adder as well as have issues related to RPM that grow exponentially as rpm increases.

If you keep the blower to 15psi, you may not see an issue with the crank. And if you can hit your target HP at that pressure you may be o.k. But bump it up to 18+psi, you're going to be stressing the end of that crankshaft in a way that no other power adder does.

Ford tested the blower on cast crankshafts, and they broke at stock boost levels. They tested them on the improved DuraCast cranks and found sucess but couldn't get DuraCast cranks with sufficient yield. Thus they went forged.

That doesn't automatically mean a Cast crank won't take the load. But it does mean there are some loads unique to the M90 type blower that you won't want to ignore in your plans.

Sounds like a fun project.
 
The biggest problem using a cast crank with the M90 is the stress on the crank snout. If you are using a single bel tto run everything this will be less of a problem..However if you are running a jackshaft setup its probably only a matte rof time till it goes. You dont need more then a factory m90 to get to where you want to be in a light car with nitrous..

And there have been 3.8 N/A non Nascar ported factory head motors making 265rwhp + I believe I had even seen over 300rwhp even.

good luck but I;d stay away from that factory crank
 
Thanks guys... Whats the highest shot of nitrous you guys run on your SC's with forged motors? I'm thinking 150 shot will do. I want to OD the blower as little as possible for my goals. It looks like a ported 94 blower, + fuel upgrades, + FMIC, + ported BV heads/cam/intake should take me to 350RWHP without too much trouble. I'm about ready to order the internals, I plan on going with a SC Crank, Eagle H beam 6.09" rod, and I'm undecided on pistons/rings, opinions welcome. Gapless rings? I'm excited to get this project rolling, I just got a new job that will let me 'play' more:D

Damon,
Please fill me in on the jackshaft setup and my options. Do you think a 10% OD pulley will put too much stress on the 'Jackshaft' setup? I am afterall relying on nitrous to get me into the 10's(10.99 will do), I plan on using as much nitrous as I can get away with.

No offense, but if you guys have a hard time getting 440 hp with a good shot of nitrous on built internals and fuel/IC/etc maybe you are doing something very wrong.
 
Most people arnt using Nitrous..Dave N has and made big power..I think we have made over 500rwhp with Nitrous thus far on an m90.

It has alot less to do with % OD on jackshaft then just the strain and weight and force of that setup on the crank. The extra extension on the crank is mostly to blame. Ive had my share of failures in taht area on nodular iron SBF cranks with roots blowers...

I;d rather go 3.8 with steel crank then 4.2..Teh power will be in teh nitrous
 
10 Second V6

No Offense here, either. But that very comment is BOUND to create offense to those who have already traveled down the road you are merely contemplating. You are talking about it, planning about it, thinkin' about it and asking questions from others who have done it before you. Others who have been working and doing it for years. You have lofty goals. Nothing wrong with that. But you need to be thinking a bit more realistically in terms of achieveable HP. When you say 150 HP from a ported 94 blower, you can expect about a 35HP increase, 50 at the most. There are limits to an M90, and those upper limits are reached with an MPIII overdriven 20-25%, using an 85mm Intake Tract. Others have tried a variety of different blowers, and it seems to me, the one with the most improvement for our V6 is the AR. This subject alone is not without its share of controversy.
Build up your bottom end strong, add some compression, do the cam and the head work. Install the ported 94 M90, along with a full 85mm intake tract, and an MP FMIC, a solid tune, and see what you get. I'd estimate you'll be in the 350-375 HP range. Then you can add the nitrous for another 50-75 HP, and perhaps you'll want the alcohol injection kit, too. After you get all this working together, consider bolting on another blower.
My point is this.... a NEW stock 94-95 engine makes 230 HP.It takes a lot of money, work and effort to add another 150HP to it. Thats a fact, and many others here have done it successfully. You don't get there by doing anything VERY WRONG, only by doing everything right. A huge shot of nitrous is not the magic answer. It may work for say, 5 runs down the strip, till you melt down all your work and $$:eek: , and have to start from scratch all over again.
Remember we are working with a V6, not a V8, or a big block. We all work to share our gains here and help each other with what works and what doesn't.

You should listen carefully to others advice, rather than call their results very wrong....You have not even got to the end of the first road yet, and there are many other intersections after that. You'll find a little humility will take you a lot farther than brash over-stated claims. Claims based on what you believe, rather than what you have proven at the rear wheels.
Please play nice here, and have a little respect.
Again, No Offense........:)
 
Out of respect for the boards... I will not reply to your comments. Lets keep this technical please. I need help, thats why I'm here. And to keep on track at this point I am only concerned with internals at this point, i'm going with a SC Crank, H beam rods(prob 6.09 length), and probably wiseco forged pistons with regular rings.

I could use some help with Compression Ratios in relation to ~15lbs of boost, and a 150 shot of nitrous. Is 10:1 safe at these boost levels?(boost is estimated at 15lbs due to porting). How does nitrous affect CR's?

Thanks!
 
Well guys, this guy has all the answers to our problem of "easily" achieving huge HP gains without melting anything....

I gotta see this........

Frit
 
I suggest keeping the compression ratio between 8.2:1 and 9.0:1. I'm using 351 H beam rods 5.956" long with custom Ross forged pistons for 8.2:1 static compression. I'm using Total Seal gapless rings and they seem to be holding up fine.

Deck the surface of heads and block as smooth as possible (like glass) and you can use MLS gaskets. I use the F-150 4.2 gaskets from Ford dealer, but the Felpro Permatorque MLS gaskets would probably seal a little better. Use APR studs and torque heads to about 95 ft. lbs using APR lube.

Melling makes the only aftermarket oil pump I'm aware of, part number is M246. Some people insist on a main bearing support girdle, but I don't really think they are needed. Stock timing chain works fine, but if you want a double roller, contact Morana.

Most people don't exceed a 100 hp shot of nitrous, but a few have used 150. Suggest a wet system at that power level.

David
 
You'll need custom pistons with that rod. Before you order your pistons, make sure you have all your dimensions at hand. I'd highly consider zeroing the deck and sticking around 9:1 compression.

Read through this thread regarding pistons as lots of info was collected during this group buy:
http://www.sccoa.com/forums/showthread.php?t=66890&highlight=total+seal+piston

When I called total seal to order my rings they felt that for my goals (over 400rwhp, 20psi) that a 1.2mm top ring would have worked better, as then they could have provided the stailess steel gapless top ring.

My ring setup ended up being total seal gapless with a top ductile iron ring with moly facing at 1.5mm/1.5mm/4mm.

I'd make sure everything is sound on your block. Note that the SC Crankshaft #4 main journal is different than the other journals and takes different bearings. Get the mains align honed, cylinders bored to true them with the mains, then deck the heads with a finish hone on the surface to get it nice and smooth. Watch the bearing clearances on the mains closely, shooting for .0025 rather than the tighter factory clearance of .001-.0015.

Make sure you inspect the surface of the front cover that the oil pump works against. It should be flat and smooth without any serious scratches.

Get the entire assembly balanced, SC engines are neutral balanced, unlike the non-sc blocks. So you will want to use an SC flexplate or flywheel, as well as a zero balanced harmonic balancer. When balancing the engine it's good to deliver those parts to the machiinest as well so the balance can be more exact.
 
fturner said:
Well guys, this guy has all the answers to our problem of "easily" achieving huge HP gains without melting anything....

I gotta see this........

Frit

This is starting to sound like a honda board... Thanks for the input?
 
rallystang said:
This is starting to sound like a honda board... Thanks for the input?
I thought you weren't going to reply to comments like this due to respect for the board? :rolleyes: and fwiw, you did start it :p

rallystang said:
No offense, but if you guys have a hard time getting 440 hp with a good shot of nitrous on built internals and fuel/IC/etc maybe you are doing something very wrong.

Anyway, David and Mike have pointed you in the right direction for the internals.

I don't think it's already been mentioned in this thread, but I'd seriously consider Swain coating your interals, especially if running nitrous. Swain coating will help eliminate hot spots and will help contribute to engine longevity.
 
Back
Top