Witch rods to use with a 3.1L stroker

[randy 77zt]

when i built my pick&pull ghetto stroker i found a 80something 810 with rods that had 9mm bolts-motor had head removed so i bought the pistons & rods.crank was diesel from pick&pull.pistons were donated by member 510six .they are stock nissan vg30dett.used stock nissan ring set for vg30dett.with n42 head compression ratio is supposed to be 8.2 to 1.engine is turboed.works out to 2960 cc.my machinist bushed the small end of the rods for the floating pins.motor has 2k miles no problems

[Challenger]

thanks i think i will go with the 138mm rods im looking to make 350hp on a n/a engine but im going to go with triple carbs more original and im tired of fuel injection its more money that way and weber carbs arent bad there not hard to work on fuel injection can get complicated and costly, and the kameari dizzy has 6 servos so for the money i think its the best deal.

 

Hmm. Id look into how much people spend from say rebello or sunbelt on a 350 hp engine compared to say the average member here running an l28et. Im also going to have to disagree with EFI being alot more expensive than a nice set of triples... I see most triples going in the $1000 range, Ive seen alot of people building megasquirt for less than that.

[RIP260Z]

Soullessjdog,

In my humble opinion its not going to be easy to get the 350hp you are looking for from a 3.1. Even my Rebello stroker (3.2l) with all their years of experience they are only getting those sorts of figures on their race engines. It takes a lot of effort to get 100bhp to the litre, let alone above that for a N/A.

 

As for the Kameari distributor, its very nice, but won't liberate a whole lot more horses than say the standard 280zx one, especially with a price ratio taken into consideration. Go with a crank fire distributorless system if you want say with throttle bodies. The throttle bodies (with their tuning ability) will probably give you a few more horses over triples.

 

You may get to where you want horse wise with a N/A stroker, but have some deep pockets

[soullessjdog]

well after seeing all of your imputs i see that its not impossible to do its just not the best option but i was thinking of long term if i ever sell the car i mite get more money than if i stayed with the turbo motor. so now im back to square one turbo build or n/a build.

[JMortensen]

In my humble opinion its not going to be easy to get the 350hp you are looking for from a 3.1. Even my Rebello stroker (3.2l) with all their years of experience they are only getting those sorts of figures on their race engines. It takes a lot of effort to get 100bhp to the litre, let alone above that for a N/A.

Rebello's hp numbers come from their engine dyno. This guy says he wants 350 whp. So that puts you squarely in the GT2 class engine with 14 or 15:1 compression a lifetime measured in hours, etc. It is totally unrealistic to think that you can get 350whp on an NA stroker street engine, even worse to be trying to figure out how to do it on the cheap.

[johnc]

And the 350hp NA GT2 engines are typically 2.4L that are spun over 8,500 rpm. I guess you could spin a 3.1L that high but I don't know of one that's done it regularly.

[soullessjdog]

so staying turbo mite be the best.

[out_riding]

I have recently purchased and am assembling a 3 litre NA stroker bottom end which I purchase the components from Rebello. This includes ~138mm Eagle rods, an offset ground stroker crank, and custom JE pistons built to match my closed chamber head. I am mating this to a race prepped Gerolamy head which has 37cc combustion chambers. This yields 10.75 to 1 CR and that is about the most I have been able to run on pump gas. The whole lower end package including the machine work was around 2200 dollars. I don't consider this excessive for a race prepped lower end. The bore and stroke combination 81x88.5 yield almost exactly 3 litres and I expect with the Elgins cam and the 44 mikunis with 39mm venturis to yield around 300 crank hp at around 7200 rpm. The previous 2.8 with cast nissan pistons and l28 rods put down ~230hp to the wheels on a loaded mustang dyno. The additional rod length with the added stroke still provides a rod/stroke ratio of around 1.72, which is important for these 2 valve NA motors.

 

While this is a lot to spend for some people, I consider it better to buy good parts than to cheap out and only have the motor last a few events. If anyone wants more info, pm me and I will be glad to provide pictures and specs.