Hi Guys,

I have built a 2.0 Longrod which consists of the following parts.

1. 156mm Howards Rods
2. Wiseco 2.3 Stroker Pistons
3. Cosworth 1.3mm Head Gasket
4. Ported Head with S90 Throttle Body
5. ATP GTX3582R

This issue is that the car is built and we had the car on the dyno mapping with SD. As much timing as we ran with no det the car made 530HP at the flywheel. Certainly not what we were expecting.

This is the first time a longrod was built which seems to be compression issues and there 2 factors which seem to be the issue.

1. To thick head gasket used
2. The block was not decked.

I have used a calculator to show you guys what compression i am most likely making.

http://rbid.ru/cr/?action=CalculateC...1997:0.3&print


I have 2 added options which i can think off without removing the entire engine and decking the block.

Option A : Use a thinner 0.8mm head gasket which will be 0.5mm less.
Option B : Deck the head about 0.3mm less

By doing this i can get a better compression rate although the stock 9 engine is 8.8

http://rbid.ru/cr/?action=CalculateC...1997:0.3&print

Does any expert engine builders know what are the squish characteristics and whats the best way forward?

 

I bet you accidentally put 150 mm rods on pistons calling for 156 mm rods. If so your piston is falling 6mm short of the deck.

 

Defo 156mm I beam Howards Rods

 

what was the exact part# of the piston you used? are you sure they are -21cc's? if they are, a thinner gasket wont help much. its just too much dish volume.

 

The part number on the pistons are K596M855

 

We normally run the pistons between 0.010-0.002 and run a .051 gasket for a squish of 1.4-1.5mm.

If you deck the head and go to a thinner gasket thats only going to give 8.2:1 which is still fairly low. If you are on pumpgas you can run more boost and timing than you could but it will most likely be a little less responsive.

The best option is obviously to get some custom LR2.0 pistons done in the compression ratio you want.

Aaron

 

Im gonna say its the small turbo not just compression thats your problem.


Edit, I didnt look at your link. I had just saw your refferance to the stock 8.8, so i thought you were around that.

 

How much was this amount of timing?

 

that turbo will make 700whp easy.

 

yeah, -21cc's. hate to be the bearer of bad news, but it looks like you need to swap pistons.

 

Thanks Aaron..............what piston do you recommend I get? Anything of the shelf or custom made wisecos?

Also which head gasket is 0.51 thick? Make or part number please?

 

I will get the details from the mapper and th SD graphs posted tomorrow......she just refused to make more then flywheel 530HP.

 

how much boost?

 

2 bar boost which equates to 29psi ...........i know you guys hate our unit values

Just to add more the car was running on 98 octane level and its an evo ix.

 

I have had good luck of using the custom manley pistons in both 2.0 LR and 2.4 LR however i have also heard good about wiseco hd series