One small thing not considered here. SLOW DRIVING IN TRAFFIC. With
4.10 Gears driving in slow moving traffic is more pleasant. All you need
to do is let the clutch out and the car will roll in traffic at 600 rpm and
the clutch will last much longer and less drive train trauma as opposed to a 3.42.

 

 

I'm in the same boat, but going to do the SpinFast, Lt, H/C first. I just want to hear that cam baby!!

 

I went headers/FAST before gears and if I had to do it over, I would go with Spin's recs and do gears first. Gears first.

 

Are you talking about gears for an automatic car? MN6's come with 3.42's stock.. I think your gonna confuse people if you dont state that your car is auto. 3.42 = same ratio as 4.10 for autos

 

To say a fast is worth .4 is garbage, there are way to many factors to determin a set time. I have a hard time believing that a geared car wont out run a fast/header car . . .. I wouldnt waist money on a fast until I had at least a H/C combo, the improvement isn't that great on a stock engine. Something about power in the ENTIRE RPM range sounds alot better than just after 6k.

 

I want to do the Spin 4.10.

 

If this is for the street only...your most important consideration is the tire you are running. The key word is TRACTION. My criteria is, if I am spinning and sliding from a dig to whatever speed, I am not going fast as I can on the street, not to mention the safety issue. If its the oem runflats you got, then I think its the headers and fast for you. I got similar on mine and my runflats can handle that, with no traction issues. I do not think that the oem runflats can handle 4.10's and if not, your looking at much more money for necessary better traction tire/wheel combo.

 

I say gears to. I love my 410s and wouldnt ever look back.

 

Several members have stated they get 3-4 tenths for 410 gears. Headers should give 25 hp and a ported fast 25-27 hp plus 5-10 for a tune.(Tune will be necessary.) We are talking 55-60 hp here. At roughly 1/10 per 10 hp, looks like 5-6 tenths. IMHO I believe the Fast and headers will be a few tenths quicker. Adding 410's to that setup would be sweet.

 

Since both JoeG and Dennis50nj did the swap with no other changes and got exactly 4 tenths is what its based on. If you have data that differs, post it, but dont go bashing verified data just to be the doubting Thomas.

Dennis50NJ still has the stock heads and cam and had the 4 tenths gain with the car so the H/C requirement to justify the FAST is also not based on facts.

Lasty you have it completely backwards. A cam does nothing under 4500rpm while the FAST starts m aking more power from 3000 up. I dont know what dyno sheet you looked at but the FAST is definitley not a 6k rpm mod. Your post is filled with misinfo.

In this dyno thre gains were minimal at 2500 and 6500rpm but still a few HP while the midband gains were a staggering 35rwtq+ in the 3500-5500 range.


In this dyno the peak power was also 27/33 at peak with similar gains under the curve again showing 3000-6500 as strong justifiable amounts and nothing like your 6k+ only power misinfo suggests. In fact saying the gains are only over 6k is pretty.....(fill in the word).

 

I did the 4.10's when my car was spinning in 2 gears. The 3.42's spun until I came off the gas pedal. The 4.10's would hook after 15 feet. If a car has a set distance it spins the tires in, a steeper gear will spin them for a shorter distance even though it breaks loose easier.

4.10's slow down the rate of rotation and let you hook sooner than 3.42's since the 3.42's are at a higher rate of rotation. It would break loose easier though but hook faster. Gears help you hook. Guys that dont have them dont know that, and always go by the myth you typed.

Guys that have really fast cars know you gear for the intended trap speed and stop adding power when you cant get it to the ground since power spins tires, not gears. So if you add 4.10's and have too much wheel spin, youre done. On the street your car is rarely over 2500rpm daily driving and light to light. The gears help exactly there and you feel it all the time. A H/C package makes more power past 4500rpm. Gears help the 1/8 mile big time and thats 0-100; kind of the type of driving you do on the street. Big HP helps the second 1/2 of the 1/4 mile or more like 100-135 in the 1/4.

 

Where did Joe_G pick up .40? I know he did pick up 3 mph. Mind you, he is a very happy SpinFast customer and was the one who recommended you to me.

About Joe_G
Signature

2005 LeMans Blue Convertible Z51 MZ6
Mods by Horsepower Sales - Pompano Beach 954-782-6700
3:90's, Spinmonster ported FAST 92, Vararam, A/R Headers w/cats, G5x3, Cometic .040 gaskets 450rwhp/408rwtq

Best times post-cam, pre-FAST 1/4 - 1.666, 11.540@121.39...1/8 - 1.666, 7.433@94.31 DA 1681

Best times post-cam, post-FAST 1/4 - 1.706, 11.414@124.48 DA 984...1/8 - 1.670, 7.354@95.10 DA 1200

 

Let me get this straight. I got a car with oem gears and runflat tires with headers and ported intake and they dont break loose or spin at WOT on street. You then got 4.10's with oem tires and you say they will spin less distance than oem 3.42's but "break loose easier"? Instead of driving 2500 rpm light to light to the grocery store, how about doing WOTfrom a red light to next light? Is not traction an issue here with 4.10's vs Headers/FAST combo?

 

Joe's initial track test was on the 1/8 mile he reported 2mph and 2 tenths in the 1/8.

From his SPINfast install thread:
This was from his post on the weiand vs FAST thread:
You can inscrease a car's power and get the mph with no increase in ET performance if you're not hooking but the mph is always an indicater of HP gains.

 

Your car isnt the one for the example and no you will not have a traction issue with 4.10's. I had 4.10's and z51 gears with 471rwhp and was able to outaccelerate cars with much more power......I had runflats. If you and I raced and you and I both broke tractioon, I would hook faster than you even with more power. Its odd to say this and for you to usderstand but it isnt a contradiction....you can make a car break loose easier with gears but the car would rehook immediately when you release it where 3.42's need more time to equalize the mph of the tire with the car.......here's why:

The thing you arent aware of because you dont have them is what happens to hook. Lets say youre at 3k rpm's in first gear with 3.42's. Thats maybe 30 mph spinning. The car then hooks when the car gets to the speed that the tires are roatating at: 30mph.

Now you get 4.10's and you're spinning at 3k rpmns which is reading 22mph on the speedo. Your car then hooks when the car hits the speed the tires are rotating at....22mph which happens before 30mph.

Being able to go WOT without breaking loose isnt a test of how fast a car is. How fast you get it to hook is with a higher power level.

My Dart (which I'm sure people are sick of hearing about) ran 6.13's with 700+rwhp and it pulled a wheelie out of the hole because it was only able to do 18mph in first gear. It was almost immediate to get that to hook yet it wouldnt hook with 4.88's.

One of two things can happen with a given power level. The car accelerates faster than the rpm's climb and then the tires and car match speed OR the car accelerates slower than the rpm's climb and then it never hits the speed of the tires because the tires are outaccelerating the car. 4.10's accelerate the car faster than the 3.42's can.

Anyone with a truck with 4 low gearing can tell you this: The car will always outaccelerate the rpms and it cant break the tires loose even though its like having 4x 4.10 gears. At redline the truck would be doing like 5-8mph.

 

To expand on what you mentioned above, unless I'm missing something painfully obvious (and please tell me if I am) an 11.54 time with a DA of 1681 ft would have equated to an 11.44 timeslip (approx.) in a DA of 984 ft, meaning that nothing more than just the difference in the air would have responsible for all but .026 of his better ET.

 

Now check with Joe about how many times he has run the car with the same gains on many different days.

MPH was due to a single day's DA.

 

While that may in fact be the case, I'll betcha his better times all had similar DA's which were significantly lower. I mean, 1681 ft for a track that only sits at 21 ft above sea level to begin with is a really nasty DA.

I am absolutely 100% behind doing whatever it takes to make your car go faster, but your numbers just aren't supporting your claims here.

Again, if I'm wrong (which I've known to be on hundreds of occasions) please post up some before and after numbers that make sense when accounting for the DA in addition to everything else.

 

You will bet? Make claims backed with facts and not bets implying something. Witch hunts often prove what you need them to. As far as my numbers: the FAST gets 30/30 under the curve. By the way, the temps for JoeG were also 10 degrees colder which also made his car faster. The FAST does nothing for the track then.

OK................. I voted gears. Back on topic.