6.0monsta

iTrader: (7)

If my car is currenty running 10.79@127mph.....

If I go from a 416ci to a 450ci keeping same heads, with slightly more compression and a slightly larger cam....

1) What could I expect to gain whp/tq?
2) What could I expect to gain et/mph given same 60 foot?
3) Would the extra cubes be faster or the same as a 125 shot on my current motor?

ATVracr

iTrader: (5)

No way 35 cubes makes the same as 125 shot.

6.0monsta

iTrader: (7)

Well what do you think I can get with the extra cubes?

Trying to decide what direction to go. Both would cost about the same after selling my current motor.

ATVracr

iTrader: (5)

50-60hp and the same for torque.

Nitrous kit cost the same as bigger motor?

JL ws-6

iTrader: (50)

You might see 60 rwhp/rq, definitely will need moce camshaft, might need bigger headers/exhaust and intake to feed it...

No way a 125 shot won't get you way more gains at the track.

You'd have to be going from a pump gas 416 with a 220's duration cam and 10 to 1 compression to a 450 with 14.5 to 1 compression, 270's duration camshaft, solid roller, etc to get the same result.

Now build that bigger motor and spray it, that's another animal

BlackScreaminMachine

iTrader: (17)

Unfortunate the question/statement is flawed, increasing cubic inches requires a heads and cam to match. I had that issue with my LT1 383. Def not enough cam, and LTX head flow sucks compared to LSX so it was a loosing battle in a lot of ways.

I understand you said "slightly", I prefer the term "Matched" as picking a valvetrain and head set up to match the new found room in the block and increasing the compression to either max effort pump gas or like JL said, go for broke and go straight race fuel. So if your going for race fuel, your not going a little over the threshold, your going 2-3 pts above the max pump gas allows.

But def listen to JL and ATV as they def have gone fast and understands what is needed. I do to, to a degree, my issue above all else is race weight...... ugggh.

6.0monsta

iTrader: (7)

I would keep exisiting TFS235 heads. And match the cam...but I have an auto so I can't go too big on the cam.

The cost would be the same after I sold the existing shortblock to help pay for it. I'd like to go from 10.79-10.83 to 10.20-10.30 with the motor or shoot for 9.9 with a 125 shot. Just not sure if either goals are doable. I'm more of a mild mannered car guy. Don't want a surging crazy cam. My existing 236/238 cam in my 416 is about as crazy as I'd go as far as driveability. I already have some surge at 40mph.

Compression would go from 11.3 to maybe 12.0 max. Cam would go to a low to mid 240s I'd imagine. Exhaust would remain the same either route.... 1 3/4 headers" & 2.5" catback.

With all that said which route would you go?

ATVracr

iTrader: (5)

A 416 with 235's on it should be able to go 10.30's on motor.

I have an auto with a 900 lift cam ... you can put a big cam in a auto car.
You need a better tuner or a looser stall.
Go fast or have a nice driver hard to get both.

6.0monsta

iTrader: (7)

This is in a GTO, not an fbody. I tried a looser stall. I went slower. It put down 504/491 through a built/stalled/geared/a4.

JL ws-6

iTrader: (50)

If the car went slower with a looser converter n/a, I'd bet either the car spun or the tranny is slipping, or the converter effeciency was junk.

N/a cars love loose converters.

ATVracr

iTrader: (5)

GTO ... just spray it.

Shawn @ VA Speed

iTrader: (3)

that statement is flawed-you do not want a converter to stall higher than the tq peak,and anytime you loosen a converter it becomes less efficient.
every engine has its sweet spot for converters=otherwise we would run 6000 stall coverters in everything.

6.0monsta

iTrader: (7)

Shawn, what do you think....you built the current motor and would build the next motor.

Motor runs badass now and I know another one would run well too. I'm having a hard time deciding. I'm an NA guy but I know nitrous would provide more for the money.

I'm trying to look past peak numbers. I realize both options would provide more area under the curve.

It's important to note that I requested Shawn build the current engine for NA with no plans ever to spray. So if I went the nitrous route I'd be limited to 100hp or so.

JL ws-6

iTrader: (50)

I agree with you... but there's 2 cars I can think of that started out with converters that were in the 4500 rpm range, and they're up to 6000 rpm 8 inch converters now and have gotten faster every time they went looser. Both over 400 inch (one is a 406, other is a 421)

Granted, these are high strung small block cars that pull to 8500 all day long, and neither have ever been on a dyno, so the results they're seeing may be just because of what you're saying. You know how old school guys are. Computer in the car? Dyno? Blah that's a waste, track is the dyno.

6.0monsta

iTrader: (7)

Has a built tranny through Performabuilt. No way that thing was slipping.

I think the motor was just pulling through the converter. I've had good luck with less stall. Current stall is a 3200. Flashes to about 3500.

The decision is hard because Shawn built the **** out of the current motor. Does not burn a drop of oil and runs it's *** off. I have the second highest NA trap speed for a GTO second only to a 454ci. It's just such a pain to pull the motor, ship it, etc but I know Shawn would make it worth it with his ninja skills. Part of me wants to run 9s. The other part wants to go after the NA GTO record as far as I know is 10.40@131.

Part of the decision is based on whether someone has the cash to buy my existing shortblock.

6.0monsta

iTrader: (7)

I have a mild setup with 3.91 gears. I'd rather let the tq of the motor and the 3.91s pull me off the line and let the converter be effecient and put down all the power the motor makes. This has gotten me consistent 1.50-1.55 60 foots driven to and from the track with no tire/wheel changes.

Shawn @ VA Speed

iTrader: (3)

you know how i feel

JL ws-6

iTrader: (50)

Your results are good.. but with a good full slick, more gear and a looser converter I think the car would go faster. if you've tried a looser converter and it didn't work then I may be wrong, but as a general rule, a looser converter usually makes an n/a car faster.

3200 is pretty tight, most of the guys I know with n/a cars are running 4800 to 6000 converters. But, every car's different, your setup may just like what you've got in it.

BlackScreaminMachine

iTrader: (17)

JL and I have had countless conversations about this as well with thechef and what it boils down it is like said. All cars have a sweet spot and when it comes to persay a given car that all cars will react differently to converters and probably one of the most expensive cost of a build after the initial investment is.... Fine Tuning.

Going to the track with 4 different converters and 6 sets of different tires and spending all day to figure out what is optimal is a large expense and that like JL said, the track results is where it is at.

Hell you can have a given company make 10 converters of the same size/ stall etc etc and run on the same car and there will still be variations after weather/track conditions have been factored out.

I often recommend gear choice and stall choice at the end of the build, not at the beginning, you could guesstimate where you want to be, or what you need, but what makes the car work can take some time.

6.0monsta

iTrader: (7)

Raceweight is 3505.

I always set my cars up to be good manered street cars. I have to drive to and from the track. And I prefer to do it on the tires I drove there. Makes it more challenging. I honestly doubt a slick would help. My car doesn't spin at all right now on good track prep. I already have lightweight wheels.

I think the converter I have now is the best all around. Good day to day and runs good at the track. The car has GOBBBBBBBBBS of torque so I think that helps it leave well.