Im making this thread to show the progress and results of my 2.5L build. I was originally going to do a standard 2.4, but I rode in a friends custom 2.45 build and I fell in love with the mid range and top end power. The car at 5-6k rpm felt like a modded F22C at peak power. He designed the kit himself and it is much better than the standard kits readily available. It has high compression and the rod a little longer than whats normally offered. He ended up with a 1.48 rod stroke ratio. He is claiming north of 330whp with a custom IM and a 90mm throttle, but I dont have the graph to back it up. I will soon be putting his car back on the dyno and will post up the results.
So i was going that route, which my friend over DNA performance designed, till i got in contact with a buddy who is an expert in engines and we decided to get pretty exotic with the internals. What we ended up with a rod stroke ratio over 1.5 , for reference the K24 has a r/s raito of 1.55 and has a taller deck height. My piston, pin and rod combo weighs around 800 grams. Compare that to the OEM which is about 1,113 grams, a difference of ~300 grams, its almost the equivalent to running the OEM rod and pin without a piston. Piston diameter is 89mm,. Im going for max compression, I will have that info when i can the block back from the machine shop and verify deck height and which head gasket thickness im going to run based on PTV clearance. The head consist of a complete Ferrea drivetrain and BC cams. The max RPM limit will be based on where the power drops off with the BC cams, this engine would be good for 10,000 rpm considering the combo but i know these cams will fall off WAY before that. The reason im going with the BC cams is i want a big mid range, since I want this to last forever I chose not to get rev happy, but thats not set in stone LOL. The only thing pending is me choosing a machine shop to sleeve my block. The head I found a trustworthy shop to do the machining.

Im super excited. My original aim was for 280whp but im now aiming for north of 300 with this setup. I know a few people are going to reccomend changing cams, which i am considering. But with the issues I have seen the TODA and skunk2 cams have, it scares me LOL. I also have a build thread going to show progress of the whole build. https://www.s2ki.com/forums/automoti...o-mod-1197941/

 

What are the issues with Toda cams?

 

They had issues with the grind and it was ruining peoples engines. They have since addressed the issue from what I was told, But im not familiar with whos doing their grinds, so I havent considered them anymore.

 

Ok i've read about that in very old threads here on the board. People told me they made like 24K Miles or more including race track sessions and all running strong. So i think the newer cams should not have these issues.

 

I wonder if there is a way to know the difference. How would i know i didnt get an old stock cam.

 

Yes, there is a way to tell the difference. Toda completely changed the core material around 10 years ago to solve the issues some people had. The updated cores are billet and are all silver. Toda grinds their cams in house. You're not somehow going to buy a 10 yead old NOS Toda cam lol.

 

You never know man LOL. But thanks for the info. Im going to check them out. I have to send the cam specs to my buddy to verify whether the specs are within my tolerances since I went so aggressive with the piston and rod combo.

 

The newest cams (newest as in like they have been this way for 5 years-ish iirc) actually have slightly more lift on the Bs and Cs (this is why they are called B2 and C2) so if it has a B2 or C2 part number it is a billet core.

 

A couple FYI's

1. I dont know what your piston is in relation to the deck height, but get adjustable cam gears. With those pistons and the RPM you are wanting to turn, PTV is more than likely going to be an issue and you'll end up not being able to run the optimal cam timing, but rather what the PTV clearance will allow. I ran into that issue with my F24 and BC cams with 11.6:1 comp. and your pistons look a helluva lot more aggressive than what I was running.

2. Dont let billy bob sleeve that block. Send it to inline or someone that has done F series before. Mid sleeves can warp the mains.

Hope you don't have to do many, or any rebuilds for that matter. 90mm is max bore on these...

 

All very valid points. The adjustable cam gears is a very good idea and i have been considering that. The rotating assembly was spec'd for the BC cams and max rod length possible and having the pistons made with big valve reliefs. The gentlman who spec'd the setup took everything from cam to chamber cc and deck height into consideration on a worst case scenario bases. My must have goes was very high compression and over a 1.5 rod stroke ratio. He knocked it out of the park from what the math is saying. Also on you ptv point, i havent yet ordered a head gasket. Once the block and head are done, and we know the cc's in the head, final deck height and figure the exact value of compression will i order the head gasket. So i have a way to gain clearance if needed.

2. Yea im between Inline, Golden or Darton.

You and i both. I wanted a 2.5 so i went near max. Im splitting hairs on the build as to make it as reliable as possible. I have built a few engines and they non have ever failed. I busted a valve on one but that was after 2 3rd to 2nd shifts at wot shifting at 9k rpm in my evo after 4.5 year lol
no one is perfect, but in trying my darnest to be when putting together an engine.