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Robbie
Robbie PowerDork
11/6/17 9:30 p.m.
Dusterbd13 says:

The last part of me wants to do both

Twin nitrous? Dual nitrous? N2O4?

Its such a good idea I don't even know what to call it.

Dusterbd13
Dusterbd13 MegaDork
11/6/17 9:31 p.m.
Robbie said:
Dusterbd13 says:

The last part of me wants to do both

Twin nitrous? Dual nitrous? N2O4?

Its such a good idea I don't even know what to call it.

Two of the big ones. By tonight harry.

STM317
STM317 Dork
11/7/17 4:25 a.m.

How would you size injectors for something like this? You'll need different amounts of fuel flow for each boost level/fuel type/power adder that you use. Maybe you can just get giant injectors and hope that a custom tune for each insano-level can properly control fueling?

mazdeuce - Seth
mazdeuce - Seth MegaDork
11/7/17 6:52 a.m.

What AX tires? More power is always good but if you can't get good rubber under the car then the boost will be wasted around the cones. In that case you just need the extra ponies for a straight line, and happy gas would be the way to go. If you can track down a set of Hoosiers, look at what sort of power they're putting through them nationally in the P or M classes. For instance, they guys I talk to who run CP say that somewhere around 600hp they stop seeing times drop. If you could tune to run a mild nitrous shot at the AX you might have all the power you need without the complications and weight of a turbo/intercooler.

Dusterbd13
Dusterbd13 MegaDork
11/7/17 7:03 a.m.

At the moment, wr have sm7 Hoosiers. 

Reason for the stages, in all honesty, is to know when to quit. At some point, more piwer stops helping. 

Naturally aspirated, this drivetrain doubles what the car had in bith horsepower and torque.  Im just not certain that its enough. 

But there is never enough when it comes to the strip.

mazdeuce - Seth
mazdeuce - Seth MegaDork
11/7/17 7:18 a.m.

Right, but you can reach the limits of the engine with nitrous and fuel on the strip. At least once.

All you're trying to do is make tires go fast. I suspect you'll see more AX gains with a NA motor and testing than all of the time and $$ of a turbo and less testing. Make sure you build in the room for a turbo, but I'd estimate it at something like priority #4. Getting the car properly tuned to AX on the tires you have should be #1. Then all of the mess that goes with nitrous and the car surviving drag launches is #2 and #3 (and  you need drag tires, we know that) and finally, adding more power for the AX.

Dusterbd13
Dusterbd13 MegaDork
11/7/17 7:22 a.m.

In reply to mazdeuce - Seth :

Want to remotely join the team? Super slow 2....

mazdeuce - Seth
mazdeuce - Seth MegaDork
11/7/17 7:24 a.m.

Spent my kid pickup time yesterday thinking about making composite doors. Don't gut the ones you have. If I can figure it out then you can sell the ones you have to more than offset the material cost of the composite ones. I'll probably pick some up locally to make molds. So.......yes?

Dusterbd13
Dusterbd13 MegaDork
11/7/17 7:30 a.m.

You are awsome!

 

And i hadn't planned to gut them. After challenge, it will get reverted to a street car. 

Its also going to be rustoleum sail blue....

Mr. Lee
Mr. Lee UberDork
11/7/17 7:38 a.m.

It's got to work better than a plywood nitrous plate. 

Mr. Lee
Mr. Lee UberDork
11/7/17 7:45 a.m.
STM317 said:

How would you size injectors for something like this? You'll need different amounts of fuel flow for each boost level/fuel type/power adder that you use. Maybe you can just get giant injectors and hope that a custom tune for each insano-level can properly control fueling?

9 years ago when we started on the mumpkin megasquirt had a very hard time idling 550cc injectors. by the time we brought it back for the second time, we had worked out the tune so it idled decently well and we didn't have to unplug the fuel pump after the priming pulse to start the car. (it would actually just flood it to the point it wouldn't start). We also figured out a cheap FPR that wasn't getting it hind end kicked by the walboro in the tank.  Modern tuning, can tone down some seriously large injectors. Used to be you ran a second set of injectors for higher boost, now days that's far less common. 

GameboyRMH
GameboyRMH MegaDork
11/7/17 8:56 a.m.

Here's a slightly less explodey idea: meth + boost + IC water spray + maybe scramble boost?

Dusterbd13
Dusterbd13 MegaDork
11/7/17 8:57 a.m.

What is scramble boost?

GameboyRMH
GameboyRMH MegaDork
11/7/17 9:00 a.m.
Dusterbd13 said:

What is scramble boost?

Short-term computer-controlled overboost. You could set it to run at the same time as IC water spray for example.

Edit: In the '90s there were standalone scramble boost controllers, they wouldn't be worth much today, hint hint wink

STM317
STM317 Dork
11/7/17 9:18 a.m.
Mr. Lee said:
STM317 said:

How would you size injectors for something like this? You'll need different amounts of fuel flow for each boost level/fuel type/power adder that you use. Maybe you can just get giant injectors and hope that a custom tune for each insano-level can properly control fueling?

9 years ago when we started on the mumpkin megasquirt had a very hard time idling 550cc injectors. by the time we brought it back for the second time, we had worked out the tune so it idled decently well and we didn't have to unplug the fuel pump after the priming pulse to start the car. (it would actually just flood it to the point it wouldn't start). We also figured out a cheap FPR that wasn't getting it hind end kicked by the walboro in the tank.  Modern tuning, can tone down some seriously large injectors. Used to be you ran a second set of injectors for higher boost, now days that's far less common. 

I was thinking similar, but you have to create different tunes for each "level" which takes loads of time (and/or money) to do properly. Also, really high flowing injectors tend to be pretty pricey. Not sure how that fits into a challenge budget, but I'm in for the build thread to be proven wrong.

Dusterbd13
Dusterbd13 MegaDork
11/7/17 9:23 a.m.

Theres the beginning of the build thread here, with no real content. Were still in parts acquisition and planning 

sleepyhead
sleepyhead HalfDork
11/7/17 11:17 a.m.
mazdeuce - Seth said:

Right, but you can reach the limits of the engine with nitrous and fuel on the strip. At least once.

All you're trying to do is make tires go fast. I suspect you'll see more AX gains with a NA motor and testing than all of the time and $$ of a turbo and less testing. Make sure you build in the room for a turbo, but I'd estimate it at something like priority #4. Getting the car properly tuned to AX on the tires you have should be #1. Then all of the mess that goes with nitrous and the car surviving drag launches is #2 and #3 (and  you need drag tires, we know that) and finally, adding more power for the AX.

along these lines... keep in mind that a 100hp corolla with no suspension was ~5sec off ftd?  And ftd was set with an open diff (if I heard that correctly on the livestream)?  so 1800# / 100hp = 18#/hp... vs. 2200# / 250hp = 9#/hp... might be enough for the AX course?

Mr. Lee
Mr. Lee UberDork
11/7/17 12:44 p.m.

It was a running joke for the time I was there that "we put all this time and effort into building these things, yet a stock looking Miata is still in the top 10"

 

SVreX
SVreX MegaDork
11/7/17 12:57 p.m.

It's still a fact. 

Some guys spend years building a Challenge car, and a bone stock Miata is still the time to beat. 

Its not a joke. Take a look at the scores this year. It played out. 

SVreX
SVreX MegaDork
11/7/17 1:00 p.m.

We all love crazy ideas. 

I am of the opinion that a well executed, proven idea with plenty of testing time will win the Challenge every time. 

The problem is we are all procrastinators, and suck at careful prep and tuning. 

Rather than spending huge energy researching and trying to reinvent he wheel and come up with a formula no one has done before, it might be easier to spend half as much time researching the best that has already been done with your platform and trying to replicate it well. 

I know. Where's the fun in that?

Dusterbd13
Dusterbd13 MegaDork
11/7/17 2:17 p.m.

The honda v6 in miata seems relatively well beaten, so im not deviating too much there with a gm 3400.

 

And sleepyhead and mazduece make very good points about power/weight/grip ratios. 

Lots to think about here.

 

Broad plan if y'al are lost:

2000 miata

2004 la1 3400 v6

1998 camaro t5 

Power adder

Spec miata slicks

Stitch welded chassis 

wvumtnbkr
wvumtnbkr UltraDork
11/7/17 2:54 p.m.

How much do you have into that LA1? 

3500 that makes more powars.... Around 250$

I think I saw you had 125 into the trans, right?  If so, that sounds pretty good!  Especially if it had a shifter or slave cylinder!

 

I REALLY wanna boost and or nitrous my chumpcar (LA1 powered 87 RX7) for hooning next year.  Maybe you and I can compare notes once the sillyness ensues....

 

 

Dusterbd13
Dusterbd13 MegaDork
11/7/17 2:56 p.m.

125 plus tax including the bellhousing, shifter, slave, and torque arm mount.

75 in the complete drop out 3400 with accessories wiring and computer. 

0 in the miata 

50 in nitrous 

Matthew Kennedy
Matthew Kennedy Reader
11/7/17 4:05 p.m.
sleepyhead said:
mazdeuce - Seth said:

Right, but you can reach the limits of the engine with nitrous and fuel on the strip. At least once.

All you're trying to do is make tires go fast. I suspect you'll see more AX gains with a NA motor and testing than all of the time and $$ of a turbo and less testing. Make sure you build in the room for a turbo, but I'd estimate it at something like priority #4. Getting the car properly tuned to AX on the tires you have should be #1. Then all of the mess that goes with nitrous and the car surviving drag launches is #2 and #3 (and  you need drag tires, we know that) and finally, adding more power for the AX.

along these lines... keep in mind that a 100hp corolla with no suspension was ~5sec off ftd?  And ftd was set with an open diff (if I heard that correctly on the livestream)?  so 1800# / 100hp = 18#/hp... vs. 2200# / 250hp = 9#/hp... might be enough for the AX course?

Yep, open diff on the Insight.  Subaru front LSDs for the 5MT are expeeeenssive.  1900lb / 230hp = 8.25 lb/hp.

The limit in the autox for the car was probably the diff.  It was doing lots of corner-exit one-tire-fires.

Mr. Lee
Mr. Lee UberDork
11/7/17 4:49 p.m.
wvumtnbkr said:

How much do you have into that LA1? 

3500 that makes more powars.... Around 250$

I think I saw you had 125 into the trans, right?  If so, that sounds pretty good!  Especially if it had a shifter or slave cylinder!

 

I REALLY wanna boost and or nitrous my chumpcar (LA1 powered 87 RX7) for hooning next year.  Maybe you and I can compare notes once the sillyness ensues....

 

 

 

Does the intake manifold flip 180 on those?

 

Hot ticket would be to find whoever picked up the parking lot build fiero a few years ago and see if you can't score those manifolds. It was a 3.4 swapped, T3 turbo'd contraption.

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