possible to detune motor for street use?

[HachiRoku]

so after months of search im finally in the process of purchasing a swift 08 with a toyota 4AGE and it got me thinking, is it possible to detune a motor for street use, im trying to build an engine that complies to the JTC-N2 regulations or at least something similar, and i started thinking, could i make my engine similar to the TODA racing ST3 crate engines? my first thought was to lower the compression and reduce the rev limit from 12k to 9 or 10k, and running E85 instead of conventional fuel, and adjusting the valve timing to be a bit less aggressive. if anyone has any tips please feel free to respond

[David Ferguson]

Best way to remove power, reduce the ignition timing, and close the throtte (restrict the intake). For small displacement engines, reducing the revs also reduced power as they make horsepower by increasing the engine speed (as opposed to increasing the torque).

[HachiRoku]

Best way to remove power, reduce the ignition timing, and close the throtte (restrict the intake). For small displacement engines, reducing the revs also reduced power as they make horsepower by increasing the engine speed (as opposed to increasing the torque).

my issue isnt exactly the power, its reliability, the JTC-N2 motors have a rebuild interval of like every 3 races, and i think formula A is every other race, im trying to find a way to use a formula A/N2 spec motor in my street car without it being a major pain in the ass, im hoping to keep at least 200-220 hp

[Rick Kirchner]

How is a 220 HP 1600cc race motor in a street car NOT going to be a PITA? No torque, short (and unbelievably expensive) life. The thing about these small sorta "spec" formula car engines is that they are built to a spec that's almost worn out from a street engine perspective to lower a lot of the internal losses - because so much of the rest of the engine is restricted. Remove those restrictions and you can build the motor to last longer. The other aspect of course is that the relationship between HP gan and longevity is not linear....

Get a Honda out of a S2000 and call it a day. Or lightly build something like a Nissan Altima 4 banger. You could easily get to 220 with one of those with a re-flash and some cams. Or an Esslinger 2.3L Ranger. For the street, there's no replacement for displacement.

Heck, for the kind of money you would spend on a AGE rebuild you could build up a 2+Liter aluminum block YAC with all new parts from Burton....

I suppose the bigger question is define "street car" - as in use case. So Cal? Plan on swapping motors every two years to get a plate?

[Chris Livengood]

Yeah, an Atlantic motor in a street car is not a great idea. That's putting it nicely. There are just so many better options.

[Pi_guy]

On a run to NYC last night. There was a rice burner trying to make time as I was. The joy of having a V8 with big brakes is just hard to beat.

[HachiRoku]

How is a 220 HP 1600cc race motor in a street car NOT going to be a PITA? No torque, short (and unbelievably expensive) life. The thing about these small sorta "spec" formula car engines is that they are built to a spec that's almost worn out from a street engine perspective to lower a lot of the internal losses - because so much of the rest of the engine is restricted. Remove those restrictions and you can build the motor to last longer. The other aspect of course is that the relationship between HP gan and longevity is not linear....<br>
<br>
Get a Honda out of a S2000 and call it a day. Or lightly build something like a Nissan Altima 4 banger. You could easily get to 220 with one of those with a re-flash and some cams. Or an Esslinger 2.3L Ranger. For the street, there's no replacement for displacement. <br>
<br>
Heck, for the kind of money you would spend on a AGE rebuild you could build up a 2+Liter aluminum block YAC with all new parts from Burton....<br>
<br>
I suppose the bigger question is define "street car" - as in use case. So Cal? Plan on swapping motors every two years to get a plate?

<br>
<br>thats exactly why im detuning, and im not trying to go off of formula A spec, im using the TRD N2 specs, its been a goal of mine to have an N2 build since i got my corolla, so thats the plan im sticking with. but im trying to stretch out the life of the engine as long as possible, so im looking into detuning so i can make it easier in B2B traffic, as well as making it less prone to catastrophic failure, im using the TRD 1600GT "bible" as well as toda racings ST3 engine as a reference. in socal we basically define anything as a street car, believe or not im not the first person to do this, i forgot this persons name but in san Francisco someone actually street drives an 86 coupe with a ful spec formula Atlantic motor built by hasselgren.

[HachiRoku]

Yeah, an Atlantic motor in a street car is not a great idea. That's putting it nicely. There are just so many better options.

hence why im detuning the motor to be more like the TODA racing ST3 crate motors, if i havent clarified yet those are also 4AGEs

[reidhazelton]

Cool idea. Milder cam and low compression pistons and you'll be fine. (No idea where to get these parts or if they exist.) You will also want to change the clutch/flywheel assembly from something other than the 5.5 or similar multi plate setup. I drove a car on the street with that and it got old very fast - especially in SoCal (I used to live in San Diego and routinely got stuck on the expressway.) You'll have to do all your own mapping or jetting as none of the FA baselines will work. It won't sound like an Atlantic and will likely be a dog but you can do it. You'll basically have something that looks like an FA engine and is pretty gutless in a street car but it should last on the street just fine for a weekend car since you'll not be operating at high rpm constantly. You won't get 100k miles out of it. I think you'll have a hard time mounting it to a conventional street car transmission though. I believe the engine blocks have the bellhousing mounts machined off.

I'd avoid building an engine to a racing rule book spec. That will be expensive. A quality pro builder will spend time to get the last few hp and that is where the $$ comes in. On the street, you don't care about the last 5 hp - especially if you are going to detune it. Those racing specs confine the builder to certain parts (sometimes from sole source suppliers), and certain building methods that drive up costs. My vibe is you want an FA looking engine but that you can actually drive on the street. My 2 cents would be to ignore rule books and just put whatever guts inside the block that you want to achieve your objective.

[HachiRoku]

Cool idea. Milder cam and low compression pistons and you'll be fine. You'll have to do all your own mapping or jetting as none of the FA baselines will work. It won't sound like an Atlantic and will likely be a dog but you can do it. You'll basically have something that looks like an FA engine and is pretty gutless but it should last on the street just fine for a weekend car. You won't get 100k miles out of it. I think you'll have a hard time mounting it to a conventional street car transmission though. I believe the engine blocks have the bellhousing mounts machined off.

im using JTC-N2 baselines, and ive heard that i would have trouble mounting it, so i also have a stock 7-rib 4age block prepared for the head conversion

[J Leonard]

<br>
<br>thats exactly why im detuning, and im not trying to go off of formula A spec, im using the TRD N2 specs, its been a goal of mine to have an N2 build since i got my corolla, so thats the plan im sticking with. but im trying to stretch out the life of the engine as long as possible, so im looking into detuning so i can make it easier in B2B traffic, as well as making it less prone to catastrophic failure, im using the TRD 1600GT "bible" as well as toda racings ST3 engine as a reference. in socal we basically define anything as a street car, believe or not im not the first person to do this, i forgot this persons name but in san Francisco someone actually street drives an 86 coupe with a ful spec formula Atlantic motor built by hasselgren.

Search Billy, Hasselgren short block

[Raleigh]

Steer clear of the ex Atlantic engine and build a 4age engine fit for purpose. Do some research on dynamic compression vs camshaft timing and match your camshafts to pistons sets available, The importance of piston to deck clearance (squish) and piston to valve clearance. Just A few suppliers listed below I have used for many 4age engine builds.

https://www.mrpltd.co.nz/product-cat...e-performance/

https://www.rhdjapan.com/

https://www.nengun.com/

https://www.kelfordcams.com/