Adding redline stability and increasing redline...

Big P · Post by **Big P** » Mon Mar 03, 2008 8:28 pm

Just curious here. What is the factory redline on a T22SED engine? I can only assume that it is the neighborhood of 6000-6500 RPM. Would this be a safe assumption? What would be the best way to safely increase the redline to say 7500 RPM? DO they make upgraded valve springs, retainers, locks, etc. readiky available? I am only asking this becuase I am doing research in preperation for my turbo project. I was talking to slowolej who is a member here and on the j obdy forums. He suggested increasing the redline to 7500 RPM with the turbo so I can use the extra RPMs to help bring in more air to make similar engine power with less boost. Just curious to see what is out there. Thanks for any info, Paul M

exist3nce · Post by **exist3nce** » Mon Mar 03, 2008 9:21 pm

I believe your assumption about the factory redline is correct, about 6500rpm. Revving higher is a great way to make more HP without increasing torque. The only problem is that if the T22 is anything like the U20, torque drops like a rock after 6000rpm. So you would need some decent headwork and maybe a different intake manifold if you want to put a higher redline to use. Otherwise, even if you can safely rev that high, it won't make any power in that region.

Big P · Post by **Big P** » Mon Mar 03, 2008 9:43 pm

Even with the turbo attached? That would have been the only reason as to why I would have done it. My main concern with that is valve float. I was hoping to see who has any sort of upgraded valve springs, cam followers, etc to help with issues that would be encountered at higher RPMs.

exist3nce · Post by **exist3nce** » Mon Mar 03, 2008 10:01 pm

Big P wrote:Even with the turbo attached? That would have been the only reason as to why I would have done it. My main concern with that is valve float. I was hoping to see who has any sort of upgraded valve springs, cam followers, etc to help with issues that would be encountered at higher RPMs.

Yes the torque still follows the same general curve as the stock motor unless you do some headwork or other mods. And these motors stock don't make much power after 6000rpm in stock form. I'm not sure where to source better valvetrain components myself, maybe gse_turbo would know better.

kinkyllama · Post by **kinkyllama** » Mon Mar 03, 2008 10:27 pm

Big P wrote:Even with the turbo attached? That would have been the only reason as to why I would have done it. My main concern with that is valve float. I was hoping to see who has any sort of upgraded valve springs, cam followers, etc to help with issues that would be encountered at higher RPMs.

It would be kind of pointless to increase redline for the reason you stated because at the higher RPMs you'll have to increase boost for your desired hp anyway. All those parts are available, somewhere, like exsit3nce said I think daft art (gse_turbo) can get all the parts or at least point you in a better direction.

Big P · Post by **Big P** » Mon Mar 03, 2008 11:44 pm

Well, personally, I don't want to have to spin the engine over 7K to make peak power. I'd rather do it in the factory rev range as to not have to worry about overrevving valvetrain components. I also do plan on having some headwork done. Not quite sure if you would call it extensive, but just your basic squaring of the mating surface, 3 angle valve job, port and polish, bowl blend, unshroud the valves, have the valves back cut for increased flow, reshape and enlarge the combustin chambers. gasket match etc. I am looking to get some decent flow out of this head, and am shooting for a CR of 8.0:1

exist3nce · Post by **exist3nce** » Tue Mar 04, 2008 1:48 am

Big P wrote:Well, personally, I don't want to have to spin the engine over 7K to make peak power. I'd rather do it in the factory rev range as to not have to worry about overrevving valvetrain components. I also do plan on having some headwork done. Not quite sure if you would call it extensive, but just your basic squaring of the mating surface, 3 angle valve job, port and polish, bowl blend, unshroud the valves, have the valves back cut for increased flow, reshape and enlarge the combustin chambers. gasket match etc. I am looking to get some decent flow out of this head, and am shooting for a CR of 8.0:1

That sounds like some decent work, but I'm not sure what results it will have. I don't think too many ppl have done work on these heads, so the amount to be gained isn't really known. I know Nubira2.2 did some minor work by just removing the large lump in the exhaust ports and that seemed to help his top end a fair bit.

Big P · Post by **Big P** » Tue Mar 04, 2008 4:14 am

Well the TO4E 50 trim that I want to run isn't really a big turbo. I am hoping that with the port work that is done on the head, I will be able to gain a substantial amount of airflow through the head at all RPM's. This means that the VE should increase at all points in the RPM range. I am pretty sure that this will let the induction system breathe better, and allow the engine to make more power with less initial boost from the turbo. I am still trying to decide on the exhaust side A/R. There are 3 choices, but I am only going to entertain 2. A .48 or a .62. The .48 will give better boost responce and at a lower RPM, but sacrifice upper RPM power. The .62 will have more lag but be more efficient up top. I was doing some research and found that most of the Dodge Neon SRT4 guys were using the TO4E with the .48 and did back to back dyno tests. It showed minimal power losses when used in comparison to the .62 inlet. Coupled with the ceramic ball bearing center section, the smaller .48 trim was getting really respectable boost figures at 2000-2500 RPM, in the neighborhood of 8-10 PSI. In that configuration, the turbo still spooled up to 25 PSI(well above what I need) and max HP did not seem to be affected. With this being a street car first and foremost, I am leaning more towards the .48 trim. The way I see it, boost down low is good. So I say, bolt it on, and let it EAT!!!

exist3nce · Post by **exist3nce** » Tue Mar 04, 2008 6:40 am

I had a T3/T4 46 or 50 trim (don't know which one) with a 0.48 exhaust housing, it did spool quite nicely. I would say go for that.