Most you made on a 3.4 WHIPPLE?

[Givens]

did your boost drop off after 4500 rpms?
i noticed too that the top 3 guys are running stroker motors. Im hesitant to run a stroker just from what my tuner and storys i heard about strokers on 4.6's
i went on whipples website and cant find there chart, do you know where i can get it or tell me whats the max psi a 3.4 can put out?

Boost held strong to 6k no drop, I think stroker motors get a bad reputation because of improper setup. I read about lots of guys that build motors and they don't even live through the dyno tune.

According to Whipple these numbers are based on a stock Cobra no mods other than the Whipple. Like Malcolm said boost is a measure of restriction, I figured my car would make less boost than the chart but that wasn't the case.

My car has AR 1 3/4 headers 2.5 O/R X

 

[Biff-Mach1]

What downsides have you heard? I know they have a horrible rod to stroke ratio which puts a lot of side load on the pistons and they don't last as long in street engines with a lot of miles. I've also heard they don't rev as freely or quickly due to the longer stroke which makes sense. Other than that I hear lots of torque and power.

Probably because that's a very hard thing to do. It would require a specific set of conditions and engine configuration. Remember boost or PSI is just a measure of restriction to air flow. So if the 3.4 made 20 PSI on one car pulley'd identical on another car it may make 25 PSI because that motor doesn't flow as well and more air is backed up. That second motor would likely make less HP. See the problem there?
A better measurement would be what HP level does the blower support before boost or airflow starts to taper off in the upper RPMs because the blower can't keep up.

Bummer on the spark plug threads falling into the cylinder. Was it a heli-coil of sorts that came loose or how did that happen?

Be cautious of Diamond pistons lately. You may have seen my fiasco with them recently this year. Took over 3 months to get pistons to me and then after assembling the motor found I didn't have piston to valve clearance required. Tore motor back down to discover they cut the valve reliefs in the wrong place and the intake valves were completely missing the reliefs. Had to strip bare and ship them back the pistons for replacement. They initially admitted fault then got nasty and tried to make me buy another set of pistons saying I ordered them wrong. I didn't though, had to argue and fight them for weeks. Finally got my replacement pistons but will NEVER do business with them again.

the 2nd tuner i was going with told me they do not tune modular motors, plus what you stated. i want to get the most out of the 3.4 and if i have to stroke the 4.6 then so be it. just hearing all these issues with stroked modulars im kind of veering away and might just keep it stock stroke.
thats right, i remember now. i check almost everyday to see if you have any updates on your build. cant wait to see how she turns out.

what do you think would cause boost to drop from 21 psi to 16psi after about 5000 rpms? the old tuner i was with said i need the crusher

2nd tuner i went with did a compression test and found several cylinders low when removing the hose for the compression tester it got stuck and would not budge. he had to cut the hose and use an extractor to remove the fitting. took a bore scope and looked in and everything looked good. put the plugs back in and decided that i would get the engine rebuilt to bring compression back to normal. after about 5 minutes of driving it started miss firing and shacking. the tuner came out and looked at it and followed me back to the shop. he tried new plugs a good loner set of coils etc. no luck. finally checked all cylinders with the bore scope and in the one cylinder he found some of the thread had broken off and fell onto the cylinder. not his fault i think and it happens, bad luck.

the car has rossi pistons in it now. im going to take the enigne to HPP and let them go at it. i heard there one of the best builders in texas. going to see what the recommend on pistons, rods etc. hopefully this will be the 3rd and final tuner/builder i go with.

 

[Biff-Mach1]

skip the diamonds and billet crank. you dont need billet crank, an oem one will hangle 1k hp with ease. i would get the gibtec pistons that Ed helped design.
http://www.modularfords.com/content/329-Off-The-Shelf-(OTS)-Custom-ModMotor-Pistons

you might as well get your heads ported if you havent already.

those pistons look great! ill put those on the maybe list.

 

[Givens]

those pistons look great! ill put those on the maybe list.

Yea if I was building a motor I would talk to Ed at Modular Ford, that guy knows his stuff and will walk you though it.

As far as your boost loss at 5k, my first thought is belt slip. What kind of belt are you running? What belt tensioner are you running? Also check and see how tight your belt is per tensioner mark. This big blower creates havoc on the stock tensioner, I really like the gatorback belts.

I've experienced belt slip, when I changed from the stock tensioner to the Thump, it had more range and required a shorter belt. Before I changed belts is would reach 21 psi and then fall to 15 psi, change belts and no more slip.

 

[MalcolmV8]

what do you think would cause boost to drop from 21 psi to 16psi after about 5000 rpms? the old tuner i was with said i need the crusher

As far as your boost loss at 5k, my first thought is belt slip.

My first thought too. When all else fails get slots machined into the side of your blower pulley like in this pic. The belt will bite in there and not slip.

 

[Givens]

My first thought too. When all else fails get slots machined into the side of your blower pulley like in this pic. The belt will bite in there and not slip.

I've thought about doing this, whats it cost and where's a good place to send it to?

 

[MalcolmV8]

I've thought about doing this, whats it cost and where's a good place to send it to?

You can just buy a replacement pulley already like that or just take it to a local machine shop and have them put a few slots in it. I had several things done so I forget the break down but I think the pulley slotting was like $20 or something but I also had them doing other work. Probably charge me $50 if it was all I brought them lol.

 

[Biff-Mach1]

Yea if I was building a motor I would talk to Ed at Modular Ford, that guy knows his stuff and will walk you though it.

As far as your boost loss at 5k, my first thought is belt slip. What kind of belt are you running? What belt tensioner are you running? Also check and see how tight your belt is per tensioner mark. This big blower creates havoc on the stock tensioner, I really like the gatorback belts.

I've experienced belt slip, when I changed from the stock tensioner to the Thump, it had more range and required a shorter belt. Before I changed belts is would reach 21 psi and then fall to 15 psi, change belts and no more slip.

does Ed have a website or is he only on the forum?
im running the green belt, aux pulley, reichard racing pulley with the none slip coating and reichard racing tensioner

 

[MalcolmV8]

does Ed have a website or is he only on the forum?

As far as I know just on the forums. He's a great guy. Have chatted to him a lot over the years about various topics. If my Diamonds had fallen through and I was forced to buy new pistons I was going to look into the ones he designed as it was almost identical to the changes I had Diamond do for my custom pistons. Except it sounded like the places making them for Ed had reasonable turn around times etc.

 

[mustangmanjeff]

thats good numbers. i only made 660hp on 21 psi non crusher. what pulleys did you have on to make 28psi?

That seems very low, my buddys old 03 cobra saleen was stock except for a kb 2.2 and borla exaust on only around 18psi put down over 600rwhp.

 

[MalcolmV8]

That seems very low, my buddys old 03 cobra saleen was stock except for a kb 2.2 and borla exaust on only around 18psi put down over 600rwhp.

That sounds like a happy dyno. Check the google doc spreadsheet thread with a compilation of combos and see what kb 2.2s make on average.

 

[mustangmanjeff]

That sounds like a happy dyno. Check the google doc spreadsheet thread with a compilation of combos and see what kb 2.2s make on average.

Its actually well know car its the car paul walker and roger rodas owned my friend sold it to roger rodas was in paul walkers car collection was just up for sale again on ebay. the dyno was proven dyno dynojet, so on a mustang dyno it would make right around prob 540-575rwhp. so 600rwhp on a dynotjet is right in line.

 

[countrysvt]

Mine is stock block, 3.75 upper stock lower, stock 3.4 whipple, fore fuel system w gt40 fuel pumps, mod fpdm, boostapump, stock manifolds, jlt intake. 93octane.
660/600 18 lbs

 

[SGT MERC]

Mine is a 9.1 compression motor, long tubes, 3" mandrel bent exhaust, killer chiller, stage 1 heads and stage 3 cams. 665/600 at the tires with the air condition on. 14° timing and 14lbs boost. 4" upper, stock lower

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