I need more power

[crs240sx]

I drive an ITA240 and my obvious competition is the CRX.

I finally have the car to a point where I am very happy with how it handles and brakes but I am getting toasted on the straights.
Luckily there is lots of room for improvement but I need help deciding where to spend the pennies first.

I have:
Stock block with lots of miles.
Near stock head. Recently had all new seals, valves re-done and port matched. Not plained since it was dead straight.
Stock manifold, port matched. 2-1/2" exhaust.
Stock ecu and gears

So some obvios choices are:
Rebuild the bottom end, do I go .040 over?
Plain the block or the head a bit.
Header
ECU
4.6 gears.

My home track is fairly tight. Mostly 3rd gear. 4th gear most of the back stretch and some of the front. Into 2nd for one corner. No 1st, no 5th. Not sure if the gear change would help or not since I would have to use 5th on the straight.

If you have a suggestion, sources and prices would be helpful.

Thanks
Corey

[ITA240]

Corey,
First, make sure that what you have is ok...Check compression..Be sure you use the factory specified procedure (all plugs out, etc) when doing so. IF it is low, then you will need a rebuild and at that time, you might as well go .040 over.
Running stock gear? and stock ECU? Stock exhaust manifold? big opportunity in all three areas. The rev limiter and top speed limiter on these cars are not racer friendly. Stock manifold very restrictive. The hotshot header is better than nothing. I have a S&S header with a merge collector. 2 1/2 inch also. I run a 4.36 gear everywhere except Daytona. There, I run the stock gear and am deep into 5th gear.

feel free to email me any other questions. This is only a start..

Jim
[email protected]

[crs240sx]

I have not check the compression of what I have. It is easy to do though so I'll try and report back. Is there a way to tell which pistons my motor has? It is a bone yard special so I'm not sure if it has the early high compression ones or not.

When you buy replacement pistons, do most places just sell the newer lower compression versions?

As for gears. My home track is a small one. I reach the top of 4th, just under the speed limiter.

[erlrich]

Originally posted by crs240sx:
I have not check the compression of what I have. It is easy to do though so I'll try and report back. Is there a way to tell which pistons my motor has? It is a bone yard special so I'm not sure if it has the early high compression ones or not.

Corey - as I understand it, unless you have one of the early 1989 engines you have the lower compression pistons. Easy enough to tell, the higher comp pistons are flat-tops, while the lower comp pistons are dished.

When you buy replacement pistons, do most places just sell the newer lower compression versions?

If you get them from Nissan Motorsports you can only get the higher compression slugs - they are available in .5mm and 1mm oversize. And I doubt you are going to find them any cheaper - they're around $160 a set from nismoparts.com

As for gears. My home track is a small one. I reach the top of 4th, just under the speed limiter.

Sounds like a candidate for 4.63 gears, which would put your top speed at around 115-125 in 5th(depending on tire size of course). I would bet though, with the stock 4.08 gears if you do the other engine upgrades you are probably going to be hitting the speed limiter before you run out of straight. In that case I would put the ECU before the gears. Just MHO though.

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Earl
ITA 240SX in process

[crs240sx]

Thanks for the replies so far.

How much can I/ should I take og the head/block? And is an offset cam gear required or legal?

[erlrich]

Corey - I'm planning on having the shop shave around .020" off the head when I do the rebuild (if I'm ever able to pull the engine - it may not stop raining here in VA until July!!!)(man it sucks not having a garage), but I would suggest checking your clearances before doing any shaving - you never know what the guy before you did. I would think some of the other guys here would have a better idea though (Jim? Joe? Tristan?).

As far as the cam gear, it is legal (but not required) for correcting cam timing. Nissan Motorsports sells the gear for the SOHC engine, along with a selection of offset keys.

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Earl
ITA 240SX in process

[This message has been edited by erlrich (edited May 28, 2003).]

[SpudZ]

Hey Guys,
When I get a chance this week I will check availability and prices on the Pistons and also the cam gear. According to the Nissan Motorsports catalog the stock compression is 8.6 to 1 with the dished pistons and the replacement
piston is a 9.1 to 1 .

Mike
Zdriver.com
StrictlyZ.com