So, another question I have in my putting together a FI budget is, since the weak link in the DE engine seems to be the rods, if I upgraded the rods, do you have to upgrade the pistons with it? This is what I was thinking only if i went with a Single turbo or vortech. If i went for twins I'd do the pistons. Anyone know?

 

In most applications, the wrist pin size on a aftermarket rod does not match up with a factory piston. You generally have to go to an aftermart piston.

 

thats straight stupid if you go through all that work to get the rods done and not do the pistons

ok dumb post i know .. so go ahead and give me crap for it

 

^+1

It would be a very BAD and complete waste of money and time to only do the rods and leave the pistons alone. There is no FI on a budget IMO, well at least not a motor build.

 

ya waste of time if you are gonna do the rods you should the pistons aswell

 

Yah I kind of figured I'd get these kind of replies. I'm just looking at what really NEEDS to be done. I mean, everyone says that the weak link on the DE is the rods, and no one ever has problems with the pistons, so I'm just asking why fix whats not broke. I'm not trying to get cheap, I think its valid to ask. I'd like to know what points you have to think its a waste. The HR engines seem to do ok on low boost applications with their stronger factory rods. Are the pistons in the HR the same? Pistons will add 1k. If only fixing the weak link is all that needs to be done, then how is it a waste? I understand the labor covering the rods would bascially cover for the pistons also, but again, 1k for the pistons isn't a "might as well throw it in while you're at it" cost. Instead of pistons, I figure studs and gaskets would go on. If it can't be done then it can't be done. Thats all I'm asking.


Edit-I'm saying I'm putting together a budget for the FI, not trying to get a budget FI. Please understand the difference. I'm getting a number together of what I need to have to do it, not trying to do it as cheap as possible.

 

After market pistons are also gonna lower the compression.

 

generally speaking, no.

If the aftermarket manufactures (wiseco, JE/SRP, Arias, CP etc...) have a casting for the VQ piston, then getting whatever compression ratio you want isnt generally a problem. It takes a bit more work as a custom order may need to be placed to obtain correct wrist pin heights whether or not you go with a dish/dome or flat top piston.

EvoGSR, i take it you are coming from the honda world? Take it from someone that has blown up his fair share of built turbo honda's, spend the time and money on the bottom, make sure you get a good set of pistons and rods and make sure you get setup with a solid tune/tuner.

My drag car corked 2 boosted LSvtec motors b/c of a stupid oversight in the tuning. Even the best parts can only take so much **** and abuse before they puke their guts.

best of luck to ya with your build.

 

Correct me if I'm wrong, but don't a lot of LSvtec motors fail b/c they don't come w/ the oil squirters that the Vtec blocks come with.

 

LSvtec's motor fail when ppl just slap a vtec head on a LS block and call it a day. They dont consider the increase in oil pressure that is needed at a constant rate to feed the the vtec system in the high RPM's, as well, they dont take into consideration that the factory b18 rod bolts will strectch a great deal beyond what they were meant to do after 7200rpm.

If one takes the time to install a set of ARP rod bolts, and a b16 oil pump and other simple precautionary mods before assemblying the motors, they can a long time.

my first lsvtec never saw a day NA once it was assembled and it ran strong for close to 40k kms before it cooked a piston, and that was due to 22psi being crammed into it and a rad hose failing at the top of the 1/4, severely overheating the motor and causing it to pack it in.

 

Nah, never turbo'd a car in my life, so i really don't know anything about anything, and have asked tuners many questions and will have many more questions when they come to mind. I only asked this because everyone says the rods are weak in a DE, and pistons are another 1k, and no one has said anything bad about the pistons, so it was the next logical question for me to ask. You're the only one who actually answered the question I asked.

 

The reason why you would want to do your pistons is to lower your compression, so you can get more boost. If you're doing a rods, and not pistons then it is just a waste of money, because eventually you will probably want to do the pistons.

 

I do know that lowering compression is ideal for an FI application on our cars, but what does this do? Is it for safety/reliability, more power, or..??? Would it be an advantage to lower compression on a low boost application, and if you were to remove your FI, how would the lower compression affect NA?

 

Lower compression allows you to turn up the boost more and your motor will be able to take the boost A LOT more safely. Higher compression is better for N/A motors to my knowledge, as you will get more power of it. High compression + boost is dangerous. You would want lower compression with high boost. I'd assume with lower compression and no boost, you would loose power.

 

How would lower compression on a N/A motor affect torque if it lowers peak HP?