Adding a Restrictor plate on a EFI L6

[JSM]

I'm looking at fixing up a 78 280z for my son's first car. He's almost 14. I'm going to keep it stock, but I'm thinking I may want to slow it down even further.

 

If I were to add a restrictor plate behind the TB, what results would occur? Would it make it run rich?

 

I was thinking of making the hole 30 to 40mm. Would doing this acheive the results I want?

 

Is there an aftermarket system that could be added to reduce top speed?

[ShaggyZ]

I think that's a bad idea. You could simply limit the travel of the linkage, though. But think this all out practically so that you're not limiting the power so much that it's dangerous (like trying to get on a highway)... and also making people think the Z's are slower than they are

[JSM]

I think that's a bad idea. You could simply limit the travel of the linkage, though. But think this all out practically so that you're not limiting the power so much that it's dangerous (like trying to get on a highway)... and also making people think the Z's are slower than they are

 

I'd like to have 4 cyl performance without swaping the whole motor.

 

Is it just a bad idea based on saftey?

[ShaggyZ]

Like you said, it'll probably run rich. You'd run into issues particularly when the TPS hits the full throttle contact - maybe only then.

 

Modern 4-cylinder engines are as strong as the L28

[Evan Purple240zt]

Your throttle blade will touch the plate if its between the manifold/throttle body.

 

Evan

 

Why not run very conservative timing instead? That should turn it into a turd.

[BRAAP]

...

Why not run very conservative timing instead? That should turn it into a turd.

 

Retarding the timing is far worse than the restrictor plate on many levels, mileage, exhaust heat, etc.

Limiting throttle travel would be the most effective non evasive zero impact method to limit power production. Either at the pedal in the car or at the TB or anywhere in the linkage in between. Just be "absolutely" sure your throttle limiting method will not cause the throttle to bind or stick.

[Slow_Old_Car]

agreed, just make a custom length throttle stop to replace the stock one on the floor, it's mearly a rod w/ a bumper on the end.

 

but the point about making sure the car isn't unsafe on the highway is valid too, definately would need to do some trial and error to find the comprimise point between the reduction in speed and still being able to safely navigate a modern highway.

 

my personal .02 as having daily driven a Z though, is that it is useless unless it's got very good AC, a rewired wiper motor/honda motor swap, and some good tires and fresh brakes... it's probally not the best canidate as a childs 1st car.

 

i daily drove one when i was 19, had the car a total of 3 weeks as my daily, nearly died 3 times, after that it was retired to weekend status.

 

When it would rain, it would fog up the windshield to where you couldn't see (partially from the climate here i'm sure), without the great working AC, you had to pull over and wait out the storm while cooking in the Z. Cracking the windows didn't help.

 

If you kept moving at a decent speed you might have been o.k., except the stock Z wipers are a joke, so your speed to maintain decent sight was so low it made it impossible to move enough air to keep the windshield in check.

 

Then the brakes, which this could have been partly related to my use of standard off the shelf 40-50k mile tires at the time. In any freshly watered surface condition, especially light drizzle situations, the car became a lock up nightmare. That attributed for 2 of the 3 close calls, with both instances being at speeds under 30mph.

 

I personally found a Z to be a handful for a daily driver. If yours is 100% functional then that could be different, but stuff as simple as working AC and capable wipers really should be addressed before it is to be considered an all weather daily driver.

[Clifton]

It would not run rich with a restrictor plate just as limiting the throttle wouldn't make it run rich. Even compared to modern 4 cyl econo cars, Z's aren't that fast ( 0-60, 1/4 mi, top speed). Most mini vans or SUV's would beat one no problem. I would let him drive it as is.

[rudypoochris]

I would let him drive it as is but educate him about not speeding and such. He probably will anyway, will get some tickets, then stop. Thats how people learn though and its probably best to let him learn for himself, because he is going to have to learn it later anyway. Thats just my 2 cents though as a 20 year old who happens to have a pair of speeding tickets. Hmmm.

[JSM]

100% agree and those issues will be addressed.

 

agreed, just make a custom length throttle stop to replace the stock one on the floor, it's mearly a rod w/ a bumper on the end.

 

but the point about making sure the car isn't unsafe on the highway is valid too, definately would need to do some trial and error to find the comprimise point between the reduction in speed and still being able to safely navigate a modern highway.

 

my personal .02 as having daily driven a Z though, is that it is useless unless it's got very good AC, a rewired wiper motor/honda motor swap, and some good tires and fresh brakes... it's probally not the best canidate as a childs 1st car.

 

i daily drove one when i was 19, had the car a total of 3 weeks as my daily, nearly died 3 times, after that it was retired to weekend status.

 

When it would rain, it would fog up the windshield to where you couldn't see (partially from the climate here i'm sure), without the great working AC, you had to pull over and wait out the storm while cooking in the Z. Cracking the windows didn't help.

 

If you kept moving at a decent speed you might have been o.k., except the stock Z wipers are a joke, so your speed to maintain decent sight was so low it made it impossible to move enough air to keep the windshield in check.

 

Then the brakes, which this could have been partly related to my use of standard off the shelf 40-50k mile tires at the time. In any freshly watered surface condition, especially light drizzle situations, the car became a lock up nightmare. That attributed for 2 of the 3 close calls, with both instances being at speeds under 30mph.

 

I personally found a Z to be a handful for a daily driver. If yours is 100% functional then that could be different, but stuff as simple as working AC and capable wipers really should be addressed before it is to be considered an all weather daily driver.

[woldson]

How about a rev limiter. Find out what rpm is out on the highway at cruising speed and set the rev limiter to that??

[Tony D]

Rev Limiter works for me. I had (in the dark ages) the keyswitch on the MSD 6 Box for dual RPM Pills. One was set at 2000, the other at 6700. When I would 'valet park' my shark car, they got it with the 2000rpm pill activated. MSD still sells all this stuff to run dual rev limiters.

 

Frankly, I find in everyday driving I rarely need to go over 4000 to scoot in front of much traffic in a bone stock 260Z with a 3.7 gearset. With a five speed that will still get you a big ticket on the freeway! 3K would be where a 3.7 geared vehicle would likely keep the speed down to less than 80 on the freeways...but that's still fast.

 

Get him involved in Auto-X and give him an outlet for his speed, and he will soon realize that playing around on the street is really just a joke by comparison. Once they hit 9 or 10/10'ths on the track they will realize most you could ever do on the street with other cars is so mundane by comparison that it 'isn't even worth it'---I know that is what did it for me!

 

 

Every kid should be forced to learn how to drive in a 1200cc 62 VW Microbus. It gives you two things:

Appreciation for power when you get it.

most importantly:

It teaches you patience. No matter WHAT you do in that vehicle, you WILL NOT get there any faster, so you may as well accept it and realize you get there when you get there.

[JSM]

I'm attempting to try to better what my mom and dad did for me. My first car was a 73 Ford Torino Station wagon.

 

I just want something better than that for him. He is very interested in my Z, so I got a deal on 280z.

 

A little more solid, newer A/C components and FI. I just hate those bumpers, but they may come in handy for a first car.

 

Plus I'm hoping to have him involved in the fix up.

[Brad-ManQ45]

I am going to side with Clifton and Rudy....

 

Restricting the intake will have NO effect of how the engine run as far as A/

F ratio.

 

As far as others whoi said sometihing about a 'VW Microbus, I had a '70 fastback with what to me was no power (after what I had had before) and my main concern at the time was NOT SLOWING DOWN if I was coming up on a hill.

 

I will also say that later on, power was sometimes a good thing - the ability to get out of someones' way was lifesaving.

 

The only car I had a wreck in was an underpowered car whern I was 20( VW fastbaxk), and the first 4 years of driving was in V8 powered automobiles.

 

I think it far moree important to teach/instill in your pregeny the ultimate responsibilty for one's actions and the possibility of taking a life as a deterent for unsafe/unwise driving than limiting the power of a car, which (if used wisely) can even help prevent accidents.

[Six_Shooter]

I agree on leaving it as is.

 

I work with a guy that has been screwing with one of his cars to "limit power" to allow his son to drive the car.

 

He's been playing with timing control, throttle limiting, etc. He finds that it's difficult to drive (timing control had the car surging), accel from throttle limiting was dangerous to get on a highway, he still thinks there's a way to do it.

 

Teach him about responsibility, and then go out on the car with him, showing him the proper way to drive.

 

If he's anything like I was as a kid, he'll probably have no problem finding the "power limiting" device and temporarily disabling it whil you're not around. Ever car guy I know of that had thier fathers do this to them as a kid would joke about how they would disable the limiter and then re-enable it when they went home.

 

If you want to give him a slow car, give him a slow car, not a slightly faster car, that has been detuned or modified to limit power. From what I've seen these cars are really no faster than a late '80s or early '90s Cavalier/Sunbird, which I had many of, first car was a 1981 Honda Prelude, wasn't slow, but wasn't a rocket ship either. Probably just about on par with the performance of a 280Z.

 

I really don't feel it is safe to detune or modify a car for this purpose. There have been more than a few occasions, where the best way out of the situation was by powering away from it, and if the car was limited on power I don't know that I owuld have made it out of those situations unscathed.

 

I can appreciate what you want to do though.

 

I've read about this poor wiper performance, but last week I drove an hour each way to a Z car meet, and it rained for a good 60% of the drive, and my wipers were just fine, had no windsheild fogging problems (no A/C either), just turned the DEF on, and let it go. The rain wasn't exactly light at times either.

[rudypoochris]

The fact of the matter is, no matter how slow the car it can take a life extremely easily. I drove a slow car, but that didn't slow me down. Two tickets did and the experience of driving for 5 years. It takes time, no matter how much I was told not to do this and that, it didn't really hit me until I had some experience and close calls. Its just important to make sure close calls is all he is having and nothing more. Responsibility, caring about the automobile, and keeping the car as well as his mind in top shape (not driving intoxicated... on the cell phone... showing off to friends... etc.) are what are key. In the end it is your common sense and to a much smaller degree luck that keeps you alive.

[JSM]

All very good points I will take under consideration.

 

I'm sure I'll be dinged on a two seater sports car for insurance purposes, but one thing I recognized was having more than one passanger was a huge distraction as a teenage driver back in the day.

 

It's either a Z or small pickup. What is bad about a pickup is he can pile kids in the back. Major, no, no in my book.

 

Granted he can stuff a couple of kids in the back, but it sure is nice to say I can't fit but one in the car or can I ride w/ you.

[Slow_Old_Car]

The more i think about it, the more i'll agree w/ the leaving the motor as is train of thought.

 

A focus on good tires, brakes, wipers, and AC would probally be all it needs. I'd owned, driven, and raced much faster cars before i daily drove that Z. It was a turd comparatively.

 

The real challenge from his young driver standpoint will be that 1st time someone at his school cracks a comment about his car looking fast, but getting ripped by _______. Thats always a uniquely rough situation to be in as a young male.

 

If his school mates are VW Bugs and 92-95 honda cx's he'll be fine. But if he really likes that guys girlfriend, that guy w/ the modded mustang and such, that could be a problem.

[m4xwellmurd3r]

 

 

Every kid should be forced to learn how to drive in a 1200cc 62 VW Microbus. It gives you two things:

Appreciation for power when you get it.

most importantly:

It teaches you patience. No matter WHAT you do in that vehicle, you WILL NOT get there any faster, so you may as well accept it and realize you get there when you get there.

I had a 62vw bug as my first car with a stock 1200. funny thing is, up to about 50mph it would BEAT most stock civics. they accelerated pretty decently up to 50, then fell on their face. don't have to worry about speeding tickets either. you're lucky to see 70mph in it haha.

[JSM]

That will be okay, I'll let hime bring my car if that is the case!

 

The real challenge from his young driver standpoint will be that 1st time someone at his school cracks a comment about his car looking fast, but getting ripped by _______. Thats always a uniquely rough situation to be in as a young male.

 

If his school mates are VW Bugs and 92-95 honda cx's he'll be fine. But if he really likes that guys girlfriend, that guy w/ the modded mustang and such, that could be a problem.