Motorgen Top Speed Run

[Vettezuki]

We're in planning for future events. Before I investigate costs and details, I'd like to get an idea of how many of ya'lls would be seriously interested in making formal top speed runs with your car or bike? Here are some basic parameters I can guarantee:

- At LEAST one full day
- You might only get 2 to 3 passes max
- May not be cheap, more than $100??? depending on numbers
- You'll have to sign a waiver that if you die, it's not our fault
- Willing to travel up to a couple hundred miles (depending on where you live)
- In addition to a helmet you might be required to have fire suit and at least a fire extinguisher, maybe more, depending on likely top speeds

We're talking flying mile at a deserted runway or lake bed.

[heypal]

Bikes are scary as hell just so you know on hs runs on lake beds and stuff not for the feint of heart. Bike moves around alot. But sounds cool as hell deserted runway is probably the best for the bikes.

[Vettezuki]

Bikes are scary as hell just so you know on hs runs on lake beds and stuff not for the feint of heart. Bike moves around alot. But sounds cool as hell deserted runway is probably the best for the bikes.

Good point. I know the hs bikes on the lake beds are almost all qutie modified with long swing arms and extra weigth! to stabilize them.

[enkeivette]

Hells yeah. Assuming I don't have school and that I have the money. So... June July August should be a sure thing for me.

[silvertermi04]

OMG OMG I just saw this and im so interested as long as there is time to get the cash and not to many rules like fire extigusiher and jacket.

[94cobra69ss396]

I'm in if I have the cash.

[SeanPlunk]

I'm not interested, it turns out that boost + 5th or 6th gear in a Cobra equals engine death...

[silvertermi04]

I'm not interested, it turns out that boost + 5th or 6th gear in a Cobra equals engine death...

Only if ur in low rpms from what i have heard. So if u take ur cobra from top of fourth to 5th ur good. If ur in 5th like at 1500 rpm and floor it, then ur asking for a nice whole somewhere.

[94cobra69ss396]

I'm not interested, it turns out that boost + 5th or 6th gear in a Cobra equals engine death...

Where did you hear that? If your worried about detonation in 5th and 6th just throw a gallon or two of race fuel in and you'll be fine.

[SeanPlunk]

Where did you hear that? If your worried about detonation in 5th and 6th just throw a gallon or two of race fuel in and you'll be fine.

It's not detonation, lots of people have blown motors going wide open in 5th or 6th. This post explains it. (http://www.svtperformance.com/forums/terminator-talk-229/552804-high-speed-pulls-question.html)

[94cobra69ss396]

I thought the 03-04 Cobras had forged pistons? That's a new one for me. I'm glad I put forged pistons in my Cobra. I've done a few 5th and 6th gears pulls and never had an issue.

[Vettezuki]

It's not detonation, lots of people have blown motors going wide open in 5th or 6th. This post explains it. (http://www.svtperformance.com/forums/terminator-talk-229/552804-high-speed-pulls-question.html)

ZO6 FTW. :judge:

[enkeivette]

Wow, that sucks. I've hit 140 in my car before but I was still in 4th. I wonder how my motor would do...

[Vettezuki]

Wow, that sucks. I've hit 140 in my car before but I was still in 4th. I wonder how my motor would do...

You have forged internals right? They typically have larger cold tolerances and heat into operating tolerances. This is why a lot of after market forged stroker kits light up knock sensors. They be slapping hard until heated. This also why, on these kind of built motors, you don't really want to go blasting until they are up to operating temperature and the tolerances are in place. Otherwise, they just sorta run crappy and you can get blow by etc. At least this is my understanding.

[SeanPlunk]

I thought the 03-04 Cobras had forged pistons? That's a new one for me. I'm glad I put forged pistons in my Cobra. I've done a few 5th and 6th gears pulls and never had an issue.

They have forged everything, crank, rods, pistons.

[silvertermi04]

They have forged everything, crank, rods, pistons.

but u dont have to worry about it. its only if u boost at low rpm. like my car it makes almost 14 pounds of boos. to ask it to boost that much from a 5th gear roll is alot even with forged everything at low rpms, thats why u see all those high speed runs and street racing where they take 4th up to the max and then go to 5th so they wont be at low rpms. plus even if u take 4th all the way up u can top out the car in 5th gear. dont even need 6th.

[Vettezuki]

but u dont have to worry about it. its only if u boost at low rpm. like my car it makes almost 14 pounds of boos. to ask it to boost that much from a 5th gear roll is alot even with forged everything at low rpms, thats why u see all those high speed runs and street racing where they take 4th up to the max and then go to 5th so they wont be at low rpms. plus even if u take 4th all the way up u can top out the car in 5th gear. dont even need 6th.

My understanding of the post was because of the prolonged high heat and very tight Piston to Cylinder wall clearance, not loading or stress. Basically the pistons start to bind in the cylinders as the expand too much under heat. :huh: That's what I got out of it. Also, I'm pretty sure HS runs (at least in typical Corvettes) are all done winding out 5th. 6th is just for mileage on the freeways.

[heypal]

My understanding of the post was because of the prolonged high heat and very tight Piston to Cylinder wall clearance, not loading or stress. Basically the pistons start to bind in the cylinders as the expand too much under heat. :huh: That's what I got out of it. Also, I'm pretty sure HS runs (at least in typical Corvettes) are all done winding out 5th. 6th is just for mileage on the freeways.

Thats what I have always been told.

[94cobra69ss396]

I couldn't imagine that Ford would build a forged bottom end that had too tight of clearence that the piston would expand beyond the limit of the cylinder wall. If I recall correctly weren't those engines also hand assembled by guys in SVT as well.

I'm running a Vortech without an intercooler or aftercooler and forged piston in my Cobra and I've run it hard at Willow Springs without any issues. Even after a 20 minute session in 110 degree weather.

Your Cobra has a heat exchanger to help with the intake charge temps. I'd bet that my intake temps are higher without having a cooler of any kind than yours is with your heat exchanger.

[Vettezuki]

I couldn't imagine that Ford would build a forged bottom end that had too tight of clearence that the piston would expand beyond the limit of the cylinder wall. If I recall correctly weren't those engines also hand assembled by guys in SVT as well.

I'm running a Vortech without an intercooler or aftercooler and forged piston in my Cobra and I've run it hard at Willow Springs without any issues. Even after a 20 minute session in 110 degree weather.

Your Cobra has a heat exchanger to help with the intake charge temps. I'd bet that my intake temps are higher without having a cooler of any kind than yours is with your heat exchanger.

I know where you're coming from, but it does seem to be a real issue. Here's what another user said from the same thread Sean posted.

The rebuilt of my Cobra will be done the 2nd week of January because of a 5th WOT my 1st and last one believe me!!!! I just had the estimate for the rebuilt $$$$$$ EXPENSIVE My fault no one to blame but me. Since i blew my motor there is a thread like this one that comes out each week, and someone reply by saying they did not know about the 5th and 6th gear WOT. Lets see on this thread if we have another one. I say again this subject should become a STICKY!!!!!!!!! It would save lots of motor,money,and stress,and the wife going crazy lol

[94cobra69ss396]

I'm glad I bought a 94.

[Vettezuki]

I'm glad I bought a 94.

I quite like the appearance of your generation. Not sure what those little inlets are for, but they look cool. Overall, they just have a lighter more nimble appearance. The later Cobras, which are cool in their own way, kinda have that GM Brutalism design thing going on, which I'm sort of on/off about.

[94cobra69ss396]

I quite like the appearance of your generation. Not sure what those little inlets are for, but they look cool.

Which ones are you talking about the ones on the hood or the side vents?

http://www.motorgen.com/pic/data/696/696242_53_full.jpg

[Vettezuki]

Which ones are you talking about the ones on the hood or the side vents?

http://www.motorgen.com/pic/data/696/696242_53_full.jpg

Hood.

[94cobra69ss396]

They are actually vented into the engine compartment but I don't think they do anything. They may let out a little heat when your not moving but I can't see that they would do anything at speed. By the way the hood is not the original for my 94 it's off a 98 Cobra. As are the wheels.

[silvertermi04]

I have hear of different things, like that guy that on his first one he blew it up and then there is other that "SAY" that they have done it lots of times and have not blown up. HArd to believe what u read lots of the times on the internet but i dont boos it in fifth or six. I can afford to pay for a block.

[BRUTAL64]

My understanding of the post was because of the prolonged high heat and very tight Piston to Cylinder wall clearance, not loading or stress. Basically the pistons start to bind in the cylinders as the expand too much under heat. :huh: That's what I got out of it. Also, I'm pretty sure HS runs (at least in typical Corvettes) are all done winding out 5th. 6th is just for mileage on the freeways.


That pretty much covers it.:thumbs_up: